Veterinary Ophthalmology Quiz
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Veterinary Ophthalmology Quiz

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Questions and Answers

What is the first line of treatment for slow-healing (indolent) ulcers in dogs?

  • Laser therapy
  • Debridement and grid keratotomy (correct)
  • Topical antibiotics
  • Systemic antifungals

    • What complication may arise from performing a grid keratotomy in cats with slow-healing ulcers?

  • Persistent epithelial defect
  • Corneal neovascularization
  • Corneal sequestrum formation (correct)
  • Increased intraocular pressure

    • What is a common association with slow-healing ulcers in cats?

  • Feline herpesvirus infection (correct)
  • Chlamydial infection
  • Bacterial infection
  • Viral keratitis

    • What should not be performed on horses with slow-healing ulcers?

    <p>Grid keratotomy</p> Signup and view all the answers

    Which antifungal preparation is mentioned as a treatment option for slow-healing ulcers in horses?

    <p>Fluconazole</p> Signup and view all the answers

    What is the purpose of a superficial keratectomy in cases where the ulcer does not heal?

    <p>To promote epithelial adherence</p> Signup and view all the answers

    What is a characteristic of midstromal corneal ulcers based on the presented content?

    <p>They may lead to permanent vision loss</p> Signup and view all the answers

    What might be included in the management for horses with slow-healing ulcers?

    <p>Antifungal preparations</p> Signup and view all the answers

    What is the most commonly used applanation tonometer?

    <p>Tono-Pen</p> Signup and view all the answers

    Which condition is characterized by unilateral exophthalmos with acute onset?

    <p>Abscesses and cellulitis</p> Signup and view all the answers

    Which diagnostic method is NOT mentioned for examining conditions affecting the orbit?

    <p>MRI scan</p> Signup and view all the answers

    What is the most common cause of canine blepharitis?

    <p>Bacterial infections</p> Signup and view all the answers

    Which of the following is true regarding orbital neoplasia?

    <p>It is usually nonpainful upon mouth examination</p> Signup and view all the answers

    What characterizes ectopic cilia?

    <p>Hair erupts through the palpebral conjunctiva</p> Signup and view all the answers

    Which eyelid neoplasm is the most common in canines?

    <p>Meibomian gland adenoma</p> Signup and view all the answers

    Which form of blepharitis is commonly associated with parasitic infections such as Demodex?

    <p>Parasitic blepharitis</p> Signup and view all the answers

    What is the primary physiological change associated with glaucoma during its progression?

    <p>Elevated pressure within the eye</p> Signup and view all the answers

    Which of the following is NOT a consequence of elevated intraocular pressure in glaucoma?

    <p>Improved axoplasmic flow in the optic nerve</p> Signup and view all the answers

    Which type of corneal change is characterized by gray, linear streaks representing breaks in Descemet membrane?

    <p>Corneal (Haab's) striae</p> Signup and view all the answers

    What is a common ocular condition that can result from chronic glaucoma?

    <p>Subluxated lens</p> Signup and view all the answers

    Which treatment option is primarily classified as a medical approach for managing glaucoma?

    <p>Osmotic diuretics</p> Signup and view all the answers

    In which part of the eye is aqueous humor primarily produced?

    <p>Nonpigmented ciliary body epithelium</p> Signup and view all the answers

    What anatomical feature is most affected by the pressure increase in glaucoma?

    <p>Axoplasmic flow in the optic nerve</p> Signup and view all the answers

    Which of the following explains the primary method of aqueous humor outflow in dogs?

    <p>Corneoscleral outflow</p> Signup and view all the answers

    What characterizes a dermoid in terms of its composition and location?

    <p>It consists of normal tissues located in an abnormal position.</p> Signup and view all the answers

    What is the primary surgical technique used to correct entropion?

    <p>Hotz-Celsus excision.</p> Signup and view all the answers

    Which eyelid condition is characterized by the adhesion of eyelid margins?

    <p>Ankyloblepharon.</p> Signup and view all the answers

    What is a common sequelae of neonatal conjunctivitis?

    <p>Symblepharon leading to conjunctival adhesion.</p> Signup and view all the answers

    Which of the following is a characteristic feature of entropion?

    <p>Inward rolling of the eyelid margins.</p> Signup and view all the answers

    What is the typical treatment protocol for neonatal conjunctivitis?

    <p>Separation of the eyelids and flushing with sterile saline.</p> Signup and view all the answers

    What condition reflects the abnormal growth of eyelashes from meibomian glands?

    <p>Distichiasis.</p> Signup and view all the answers

    Which of the following conditions leads to secondary keratoconjunctivitis due to anatomical malfunction?

    <p>Agenesis (coloboma).</p> Signup and view all the answers

    What is the primary function of the postganglionic neuron in the sympathetic innervation to the eye?

    <p>Innervates the iris dilator muscle</p> Signup and view all the answers

    Which anatomical components are involved in sympathetic innervation to the eye, in order from central to peripheral?

    <p>Central, Preganglionic, Postganglionic</p> Signup and view all the answers

    Which of the following clinical signs is not typically associated with Horner syndrome?

    <p>Nystagmus</p> Signup and view all the answers

    In evaluating for Horner syndrome, what does pharmacologic testing using 10% phenylephrine ophthalmic solution help determine?

    <p>Denervation hypersensitivity</p> Signup and view all the answers

    Which of the following is a potential cause of Horner syndrome in dogs and cats that occurs in more than 50% of cases?

    <p>Idiopathic reasons</p> Signup and view all the answers

    What key anatomical structure does the postganglionic neuron traverse to innervate the iris dilator muscle?

    <p>Cavernous sinus</p> Signup and view all the answers

    What is one of the main signs of Horner syndrome that indicates loss of smooth muscle tone?

    <p>Protrusion of the nictitans</p> Signup and view all the answers

    What is the role of the central neuron in the sympathetic innervation to the eye?

    <p>Relays information from the hypothalamus to the spinal cord</p> Signup and view all the answers

    What is the primary consequence of elevated intraocular pressure in glaucoma?

    <p>Optic nerve damage</p> Signup and view all the answers

    Which condition is characterized by gray, linear streaks on the cornea?

    <p>Descemet membrane breaks</p> Signup and view all the answers

    Which factor is crucial for the production of aqueous humor?

    <p>Carbonic anhydrase activity</p> Signup and view all the answers

    What anatomical feature primarily facilitates aqueous humor outflow in dogs?

    <p>Corneoscleral outflow pathway</p> Signup and view all the answers

    What is a common endocrine consequence of glaucoma due to optic nerve damage?

    <p>Ciliary body degeneration</p> Signup and view all the answers

    Which symptom is least likely to be observed during the progression of glaucoma?

    <p>Increased pain sensitivity</p> Signup and view all the answers

    Which treatment method would be classified as medical for glaucoma management?

    <p>Osmotic diuretics</p> Signup and view all the answers

    What anatomical change is indicative of retinal degeneration in glaucoma?

    <p>Increased tapetal reflectivity</p> Signup and view all the answers

    Which condition is characterized by the separation of the neural retina from the retinal pigment epithelium (RPE)?

    <p>Retinal detachment or separation</p> Signup and view all the answers

    What is the primary motor function of CN IV trochlear?

    <p>Motor to the dorsal oblique muscle</p> Signup and view all the answers

    Which of the following conditions is not a potential cause of retinal detachment?

    <p>Chemical burns</p> Signup and view all the answers

    Which cranial nerve provides sensory information for hearing and balance?

    <p>CN VIII vestibulocochlear</p> Signup and view all the answers

    What is the primary action of carbonic anhydrase inhibitors (CAIs) in the treatment of glaucoma?

    <p>Decrease aqueous humor production</p> Signup and view all the answers

    What is the common treatment approach for non-infectious diseases causing retinal separation?

    <p>Symptomatic treatment and addressing underlying causes</p> Signup and view all the answers

    Which side effect is commonly associated with carbonic anhydrase inhibitors used in glaucoma treatment?

    <p>Metabolic acidosis</p> Signup and view all the answers

    What contraindication should be considered before administering osmotic agents for glaucoma management?

    <p>Renal dysfunction</p> Signup and view all the answers

    Which cranial nerve innervates the lateral rectus muscle?

    <p>CN VI abducens</p> Signup and view all the answers

    What is the consequence of withholding water after the administration of osmotic agents?

    <p>Loss of osmotic effect</p> Signup and view all the answers

    In cases of equine peripapillary retinopathy, what is a common feature observed?

    <p>Postinflammatory scars and depigmentation</p> Signup and view all the answers

    Which condition is a known cause of secondary glaucoma?

    <p>Abnormalities in lens positioning</p> Signup and view all the answers

    What type of retinopathy is associated with high viscosity of blood?

    <p>Hyperviscosity syndrome</p> Signup and view all the answers

    Which anatomical region is commonly involved in aqueous humor drainage through uveoscleral outflow?

    <p>Iris stroma and ciliary body</p> Signup and view all the answers

    What is a potential systemic effect of severe hypovolemia caused by glaucomatous treatments?

    <p>Renal failure</p> Signup and view all the answers

    Which mechanism describes how miotics improve aqueous humor outflow?

    <p>Enhancing ciliary muscle contraction</p> Signup and view all the answers

    Which of the following accurately describes a characteristic of lens aging known as nuclear sclerosis?

    <p>It involves hardening of the central portions of the lens over time.</p> Signup and view all the answers

    Which factor is most commonly associated with congenital cataracts in dogs?

    <p>Heritable or genetic factors.</p> Signup and view all the answers

    What defines an incipient cataract based on the degree of lens opacity?

    <p>Less than 15% of the lens is opaque.</p> Signup and view all the answers

    What is a significant consequence of metabolic pathways being overwhelmed by hyperglycemia in the lens?

    <p>Precipitation of proteins leading to cataract formation.</p> Signup and view all the answers

    Which of the following types of cataracts is most likely to develop after an animal reaches 6 years of age?

    <p>Senile cataract.</p> Signup and view all the answers

    Which of the following best describes the process leading to osmotic changes in the lens associated with diabetes mellitus?

    <p>Utilization of the aldose reductase pathway for sugar processing.</p> Signup and view all the answers

    Which of the following conditions can be associated with the development of cataracts due to ocular abnormalities?

    <p>Lens luxation.</p> Signup and view all the answers

    What is an indicative feature of an immature cataract in terms of optical properties?

    <p>Preservation of tapetal reflection.</p> Signup and view all the answers

    What is the prognosis for orbital trauma involving nonreplaceable globes?

    <p>20% to 30% chance of regaining any vision</p> Signup and view all the answers

    Which characteristic is true for squamous cell carcinoma in relation to its occurrence in horses?

    <p>It shows a predilection for horses with light circumocular pigmentation.</p> Signup and view all the answers

    Which of the following statements regarding the conjunctiva is correct?

    <p>The conjunctiva serves as a first line of defense against pathogens.</p> Signup and view all the answers

    What is the most common eyelid neoplasm in cows?

    <p>Squamous cell carcinoma</p> Signup and view all the answers

    When considering treatment options for traumatic proptosis, which option is appropriate for nonreplaceable globes?

    <p>Surgical removal (enucleation)</p> Signup and view all the answers

    What is a defining feature of sarcoid neoplasms in horses?

    <p>They are locally invasive and often fibrosarcomatous.</p> Signup and view all the answers

    What is the impact of orbital trauma on vision recovery, according to the stated prognosis?

    <p>There's a significant chance of complete vision loss.</p> Signup and view all the answers

    What surgical procedure might be necessary if an orbital tumor requires significant corrective action?

    <p>Partial or complete orbitectomy</p> Signup and view all the answers

    What is the underlying cause of secondary trichiasis in congenital agenesis in cats?

    <p>Absence of eyelids resulting in exposure</p> Signup and view all the answers

    Which statement accurately describes a dermoid anomaly?

    <p>It involves normal skin elements in an abnormal location</p> Signup and view all the answers

    What represents a common sequela following untreated neonatal conjunctivitis in puppies?

    <p>Corneal perforation</p> Signup and view all the answers

    What surgical procedure is typically employed to correct entropion?

    <p>Hotz-Celsus excision</p> Signup and view all the answers

    Which factor is most commonly implicated in causing conjunctivitis in neonates?

    <p>Bacterial infections</p> Signup and view all the answers

    What type of eyelash abnormality is characterized by eyelashes arising from meibomian gland openings?

    <p>Distichiasis</p> Signup and view all the answers

    What is the primary complication associated with entropion that affects the cornea?

    <p>Abrasions due to eyelashes</p> Signup and view all the answers

    What is the typical causative agent of conjunctivitis in kittens?

    <p>Chlamydia and viral infections</p> Signup and view all the answers

    What is the primary cause of keratoconjunctivitis sicca (KCS)?

    <p>Immune-mediated destruction of tear-producing glands</p> Signup and view all the answers

    Which of the following correctly describes the feature of the cornea in relation to vascularization?

    <p>Normal cornea does not have blood vessels</p> Signup and view all the answers

    What is the treatment protocol for feline conjunctivitis caused by Chlamydophila felis?

    <p>Topical tetracycline or doxycycline</p> Signup and view all the answers

    Which phenomenon occurs when there is a loss of endothelial layers in the cornea?

    <p>Corneal edema due to fluid accumulation</p> Signup and view all the answers

    What is a significant characteristic of the inflammation caused by keratitis?

    <p>It can result in corneal scarring</p> Signup and view all the answers

    What anatomical feature is affected in cases of congenital gland aplasia?

    <p>Nictitans gland</p> Signup and view all the answers

    Which type of irritation can lead to hypersensitivity reactions in the conjunctiva?

    <p>Chemical and dust irritants</p> Signup and view all the answers

    What is often a consequence of chronic corneal irritation?

    <p>Development of pigmentation in the cornea</p> Signup and view all the answers

    What does applanation tonometry primarily measure?

    <p>Intraocular pressure</p> Signup and view all the answers

    Which factor is NOT associated with conditions affecting the orbit?

    <p>Increased tear production</p> Signup and view all the answers

    What is a common cause of blepharitis in dogs?

    <p>Bacterial infections</p> Signup and view all the answers

    What is a characteristic presentation of orbital neoplasia?

    <p>Gradual onset of exophthalmos</p> Signup and view all the answers

    Which form of ectopic cilia is described in the context?

    <p>Hair erupts through the palpebral conjunctiva</p> Signup and view all the answers

    What is the most commonly found neoplasm in canine eyelids?

    <p>Meibomian gland adenoma</p> Signup and view all the answers

    Which diagnostic method is used for evaluating orbital conditions?

    <p>Orbital ultrasound</p> Signup and view all the answers

    What is a primary characteristic of trichiasis?

    <p>Normal hair orientation towards the globe</p> Signup and view all the answers

    What primarily characterizes a Morgagnian cataract?

    <p>Liquefaction of the cortex with a nuclear remnant</p> Signup and view all the answers

    In which type of cataract is the opacity primarily located in the lens cortex?

    <p>Cortical cataract</p> Signup and view all the answers

    Which type of lens dislocation is characterized by the complete displacement of the lens from its original position?

    <p>Luxation</p> Signup and view all the answers

    What lens condition is associated with nutritional deficiencies from canine and feline milk replacers?

    <p>Nutritional cataracts</p> Signup and view all the answers

    What does senile refer to in the context of cataracts?

    <p>Age-related clouding of the lens</p> Signup and view all the answers

    Which of the following is a potential cause of anterior luxation of the lens?

    <p>Perforating injury to the lens</p> Signup and view all the answers

    What describes the primary effect of radiation on the lens epithelium?

    <p>Causes decreased epithelial cell mitosis</p> Signup and view all the answers

    How is a capsular cataract defined?

    <p>Opacity confined to the lens capsule</p> Signup and view all the answers

    Which category of retinal detachment is characterized by lesions that may lead to complete blindness?

    <p>Total RD</p> Signup and view all the answers

    What is the primary cause of primary luxation of the lens?

    <p>Degeneration of lens zonular fibers</p> Signup and view all the answers

    Which of the following breeds is primarily predisposed to anterior luxation of the lens?

    <p>Terriers</p> Signup and view all the answers

    What is a characteristic feature of rod-cone degeneration in affected animals?

    <p>Blindness occurs sometime after 2 to 4 years</p> Signup and view all the answers

    Which ocular disease is commonly associated with iridocyclitis and can lead to secondary lens luxation?

    <p>Chronic glaucoma</p> Signup and view all the answers

    What condition is described as causing joint deformities and is associated with retinal detachment in specific dog breeds?

    <p>Oculoskeletal dysplasia</p> Signup and view all the answers

    How does the severity of retinal detachment vary among individuals?

    <p>It ranges from no effect on vision to complete blindness.</p> Signup and view all the answers

    What is the primary treatment method for addressing lens luxation?

    <p>Intracapsular lens extraction</p> Signup and view all the answers

    What is the primary diagnostic method used for examining conditions affecting the orbit?

    <p>Orbital computed tomography (CT)</p> Signup and view all the answers

    Which condition is most likely associated with gradually progressive exophthalmos?

    <p>Orbital neoplasia</p> Signup and view all the answers

    What is the primary symptom of acute onset unilateral exophthalmos?

    <p>Pain only on mouth opening</p> Signup and view all the answers

    Which treatment is most appropriate for managing abscesses related to orbital infections?

    <p>Immediate surgical intervention followed by systemic antibiotics</p> Signup and view all the answers

    What type of neoplasm is most commonly identified in canines?

    <p>Meibomian gland adenoma</p> Signup and view all the answers

    What is the normal range for intraocular pressure (IOP)?

    <p>15 to 25 mm Hg</p> Signup and view all the answers

    What is a common predisposing factor for blepharitis caused by parasitic infections in dogs?

    <p>Overcrowded living conditions</p> Signup and view all the answers

    What is typically observed in cases of trichiasis?

    <p>Normal eyelash position directed towards the globe</p> Signup and view all the answers

    Which structure is part of the inner neuroepithelial layer of the globe?

    <p>Retina</p> Signup and view all the answers

    How does the Schiφtz tonometer determine IOP?

    <p>By the amount of indentation on the cornea</p> Signup and view all the answers

    Which diagnostic test would provide the least benefit when investigating unilateral exophthalmos?

    <p>Electroretinography (ERG)</p> Signup and view all the answers

    What anatomical feature indicates dogs and cats have an 'open' orbit?

    <p>Supraorbital ligament at the lateral aspect</p> Signup and view all the answers

    What is a potential consequence of primary luxation of the lens in certain dog breeds?

    <p>Corneal edema due to lens position</p> Signup and view all the answers

    What should be avoided when administering fluorescein staining?

    <p>Touching the cornea</p> Signup and view all the answers

    Which of the following is a classification of retinal degeneration?

    <p>Multifocal RD</p> Signup and view all the answers

    What is the significance of fluorescein staining the stroma bright green?

    <p>It signifies an epithelial defect</p> Signup and view all the answers

    What is a common association with retinal degeneration in Labrador retrievers and Samoyeds?

    <p>Skeletal dysplasia</p> Signup and view all the answers

    Which bones are part of the bony structure of the orbit?

    <p>Maxillary, frontal, lacrimal, zygomatic, sphenoid, and palatine bones</p> Signup and view all the answers

    What type of treatment may be required for severe cases of lens luxation?

    <p>Surgical intervention for lens removal</p> Signup and view all the answers

    Which condition leads to bilateral and progressive retinal issues in dogs?

    <p>Progressive retinal atrophy (PRA)</p> Signup and view all the answers

    What is the role of the conjunctival sac in eye health?

    <p>It serves as a reservoir for tears</p> Signup and view all the answers

    What characterizes the onset of rod-cone dysplasia in dogs?

    <p>Blindness typically occurs between 1 to 3 years of age</p> Signup and view all the answers

    Which type of RD is characterized by a widespread detachment across the retina?

    <p>Geographic RD</p> Signup and view all the answers

    What is a common ocular condition leading to retinal degeneration secondary to ocular disease?

    <p>Chronic iridocyclitis</p> Signup and view all the answers

    Which layer of the eye is the most vascular and contains the tapetum?

    <p>Choroid</p> Signup and view all the answers

    What is a characteristic feature of active retinitis-chorioretinitis?

    <p>Dull gray area with indistinct margins</p> Signup and view all the answers

    Which of the following is NOT listed as a cause for retinal hemorrhage?

    <p>Histoplasmosis</p> Signup and view all the answers

    Which congenital anomaly is characterized by choroidal hypoplasia lateral to the optic disc?

    <p>Collie eye anomaly</p> Signup and view all the answers

    What is the typical presentation of inactive retinitis-chorioretinitis?

    <p>Hyperreflectivity of the tapetal fundus</p> Signup and view all the answers

    Which condition is characterized by 'pits' in the wall of the eye?

    <p>Coloboma</p> Signup and view all the answers

    Which condition can result from infections such as bacterial-septicemia or mycoses?

    <p>Chorioretinitis</p> Signup and view all the answers

    What is a common consequence of retinal detachment in terms of visual impairment?

    <p>Total loss of vision</p> Signup and view all the answers

    What does the loss of sympathetic innervation to the eye result in?

    <p>Constricted pupil or miosis</p> Signup and view all the answers

    Which statement correctly describes the pathway of a postganglionic neuron in the sympathetic innervation to the eye?

    <p>It goes through the cranial cervical ganglion before reaching the orbit.</p> Signup and view all the answers

    What clinical sign is indicative of Horner syndrome?

    <p>Protrusion of the third eyelid</p> Signup and view all the answers

    Which condition is more commonly associated with idiopathic cases of Horner syndrome in dogs and cats?

    <p>Otitis media</p> Signup and view all the answers

    What is the primary use of 10% phenylephrine ophthalmic solution in the context of Horner syndrome?

    <p>To differentiate preganglionic vs. postganglionic Horner syndrome</p> Signup and view all the answers

    Which anatomical structure is critical for identifying the location of lesions in cases of Horner syndrome?

    <p>Cranial cervical ganglion</p> Signup and view all the answers

    What defines the central neuron in the sympathetic innervation pathway to the eye?

    <p>It originates from spinal cord segments T1-T3.</p> Signup and view all the answers

    What is a major sign of Horner syndrome related to muscle tone?

    <p>Enophthalmos due to muscle tone loss</p> Signup and view all the answers

    What is the preferred surgical technique for deep ulcers or descemetoceles?

    <p>Conjunctival pedicle flap</p> Signup and view all the answers

    Which treatment option is indicated for herpesvirus keratitis (FHV-1) in cats?

    <p>Topical antiviral medication</p> Signup and view all the answers

    What common sequelae can result from herpesvirus keratitis (FHV-1)?

    <p>Symblepharon conjunctival adhesions</p> Signup and view all the answers

    What is an important consideration when treating an infected corneal ulcer?

    <p>Administer antibiotics every 2 hours initially</p> Signup and view all the answers

    What characteristic is associated with chronic superficial keratitis (pannus)?

    <p>Commonly seen in German Shepherds and Greyhounds</p> Signup and view all the answers

    Which of the following is NOT a component of treatment for nonulcerative keratitis?

    <p>Surgery for corneal repair</p> Signup and view all the answers

    What symptom is often observed in cases of infected corneal ulcers?

    <p>Vascularization across the cornea</p> Signup and view all the answers

    What complication can occur from deep ulcers if not treated promptly?

    <p>Corneal perforation</p> Signup and view all the answers

    What is the role of cyclosporine in the treatment of tear production issues?

    <p>Reduces immune destruction of tear producing glands</p> Signup and view all the answers

    Which method is NOT useful in investigating corneal ulcers?

    <p>Ultrasonic examination of the cornea</p> Signup and view all the answers

    What is the typical healing time for superficial corneal ulcers, if untreated?

    <p>3 to 5 days</p> Signup and view all the answers

    What anatomical change does Descemet's membrane exhibit when stained with fluorescein?

    <p>Does not stain at all</p> Signup and view all the answers

    What surgical intervention is indicated for chronic dry eye when other treatments have failed?

    <p>Parotid duct transposition</p> Signup and view all the answers

    Which of the following is true regarding the use of oral pilocarpine?

    <p>It is used to stimulate tear production</p> Signup and view all the answers

    When treating superficial corneal ulcers, what is the initial recommended treatment?

    <p>Broad-spectrum antibiotics</p> Signup and view all the answers

    Which diagnostic tool is essential for determining the extent of corneal ulcers?

    <p>Fluorescein stain</p> Signup and view all the answers

    Which of the following statements best describes the key role of carbonic anhydrase in the production of aqueous humor?

    <p>It enhances ionic transport necessary for energy-dependent secretion of aqueous humor.</p> Signup and view all the answers

    What is the primary pathological mechanism by which glaucoma causes vision loss?

    <p>It damages axoplasmic flow in the optic nerve head causing retinal degeneration.</p> Signup and view all the answers

    What secondary change can be seen in the eye due to prolonged elevated intraocular pressure as seen in glaucoma?

    <p>Optic nerve atrophy resulting from ischemia.</p> Signup and view all the answers

    Which of the following options describes a potential sign of glaucoma in a canine?

    <p>Cupping of the optic disc.</p> Signup and view all the answers

    In terms of ocular anatomy, how does aqueous humor primarily exit the eye in dogs?

    <p>Via the corneoscleral outflow pathway.</p> Signup and view all the answers

    Which condition is commonly considered a direct consequence of chronic glaucoma related to corneal health?

    <p>Corneal vascularization.</p> Signup and view all the answers

    Which factor is most associated with the severity of optic nerve damage in glaucoma cases?

    <p>Duration of elevated intraocular pressure.</p> Signup and view all the answers

    What does the term 'scleral thinning' refer to in the context of glaucoma?

    <p>Loss of scleral tissue integrity leading to perforation risk.</p> Signup and view all the answers

    What is the mechanism by which osmotic agents lower intraocular pressure (IOP)?

    <p>By dehydrating the vitreous humor</p> Signup and view all the answers

    Which condition is least likely to lead to secondary glaucoma?

    <p>Vascular occlusion</p> Signup and view all the answers

    What is the primary action of carbonic anhydrase inhibitors in the treatment of glaucoma?

    <p>Decreasing the formation of bicarbonate ions</p> Signup and view all the answers

    What is a common contraindication for osmotic agents in glaucoma treatment?

    <p>Dehydration</p> Signup and view all the answers

    Which of the following is a probable side effect of carbonic anhydrase inhibitors?

    <p>Metabolic acidosis</p> Signup and view all the answers

    What anatomical pathway is involved in uveoscleral outflow of aqueous humor?

    <p>Between ciliary muscle fibers to the supraciliary space</p> Signup and view all the answers

    Which of the following side effects is commonly associated with miotic therapy in glaucoma management?

    <p>Accommodative spasm</p> Signup and view all the answers

    In the context of glaucomatous processes, which term best describes goniodysgenesis?

    <p>An abnormal formation of the iridocorneal angle</p> Signup and view all the answers

    What is one consequence of anterior lens luxation in dogs?

    <p>Corneal edema</p> Signup and view all the answers

    Which condition is associated with oculoskeletal dysplasia in certain dog breeds?

    <p>Anterior lens luxation</p> Signup and view all the answers

    What type of retinal detachment may result in complete vision loss?

    <p>Total RD</p> Signup and view all the answers

    Which breed is noted as being predisposed to anterior lens luxation due to degeneration of lens zonular fibers?

    <p>Terriers</p> Signup and view all the answers

    What eye condition typically causes blindness by ages 1 to 3 in affected animals?

    <p>Rod-cone degeneration</p> Signup and view all the answers

    What is the term for the inherited condition where retinal degeneration is bilateral and progressive?

    <p>Progressive retinal atrophy (PRA)</p> Signup and view all the answers

    Which component can secondary lens luxation in animals be attributed to?

    <p>Iridocyclitis</p> Signup and view all the answers

    At what age does rod-cone degeneration typically begin?

    <p>2-4 years</p> Signup and view all the answers

    What is the primary effect of glaucoma on the optic nerve?

    <p>Elevation of pressure within the eye leading to optic nerve damage</p> Signup and view all the answers

    Which of the following is NOT a characteristic change associated with glaucoma?

    <p>Corneal vascularization</p> Signup and view all the answers

    What role does carbonic anhydrase play in the production of aqueous humor?

    <p>It is a key enzyme in the energy-dependent secretory process</p> Signup and view all the answers

    Which anatomical feature is primarily responsible for conventional outflow of aqueous humor in dogs?

    <p>Trabecular meshwork</p> Signup and view all the answers

    What is a potential consequence of impairment in the aqueous humor outflow system?

    <p>Elevation of intraocular pressure</p> Signup and view all the answers

    Which condition can contribute to secondary keratoconjunctivitis in the context of anatomical malfunction?

    <p>Ectopic cilia</p> Signup and view all the answers

    Which factor is primarily responsible for the clinical signs of pain reduction in advanced glaucoma?

    <p>Ciliary body degeneration</p> Signup and view all the answers

    What abnormal change associated with glaucoma typically manifests as gray, linear streaks on the cornea?

    <p>Haab's striae</p> Signup and view all the answers

    What is the main consequence of a dermoid on the eyelid?

    <p>Formation of a pigmented mass bearing hair</p> Signup and view all the answers

    Which condition is specifically associated with the absence of eyelids in cats?

    <p>Agenesis (coloboma)</p> Signup and view all the answers

    What type of eyelid abnormality is marked by the inversion of the eyelid margin?

    <p>Entropion</p> Signup and view all the answers

    What is a likely sequelae of untreated neonatal conjunctivitis?

    <p>Corneal perforation</p> Signup and view all the answers

    Which of the following describes ankyloblepharon?

    <p>A condition where eyelids fail to separate</p> Signup and view all the answers

    Which eyelash abnormality involves cilia arising from meibomian gland openings?

    <p>Distichiasis</p> Signup and view all the answers

    What describes the primary treatment for entropion in animals?

    <p>Surgical correction with a Hotz-Celsus excision</p> Signup and view all the answers

    What type of conjunctivitis is commonly seen in neonates due to infections?

    <p>Bacterial conjunctivitis</p> Signup and view all the answers

    Which condition is associated with sudden acquired retinal degeneration in overweight, middle-aged female dogs?

    <p>Sudden acquired retinal degeneration syndrome (SARDs)</p> Signup and view all the answers

    What is the common appearance of the retina in the early stages of sudden acquired retinal degeneration syndrome (SARDs)?

    <p>Normal retina</p> Signup and view all the answers

    Which of the following is NOT a potential cause of vitreous hemorrhage?

    <p>Congenital malformation</p> Signup and view all the answers

    What characterizes asteroid hyalosis in geriatric animals?

    <p>Punctate calcium-lipid complex</p> Signup and view all the answers

    Which of the following best describes the lesions found in feline central retinal degeneration (FCRD)?

    <p>Elliptical lesions dorsal and temporal to the optic papilla</p> Signup and view all the answers

    What is the classification of treatment for sudden acquired retinal degeneration syndrome (SARDs)?

    <p>No treatment necessary</p> Signup and view all the answers

    In the case of vitritis, what underlying issue is often the cause?

    <p>Inflammation of surrounding ocular tissues</p> Signup and view all the answers

    Which change is a result of retinal degeneration in sudden acquired retinal degeneration syndrome (SARDs)?

    <p>Pale optic nerve appearance</p> Signup and view all the answers

    What is a primary cause of optic atrophy in horses?

    <p>Glaucoma</p> Signup and view all the answers

    Which component of the visual pathway is affected if there is a direct PLR deficit present?

    <p>Afferent pathway</p> Signup and view all the answers

    What characteristic defines the menace response in animals?

    <p>A learned response typically lacking in young animals</p> Signup and view all the answers

    What does the dazzle reflex indicate about an animal's visual system?

    <p>There is some retinal function but not necessarily visual perception</p> Signup and view all the answers

    Which reflex involves touching the cornea to assess blink response?

    <p>Corneal reflex</p> Signup and view all the answers

    In assessing for Horner syndrome, which sign is typically observed?

    <p>Enophthalmosis</p> Signup and view all the answers

    What type of nerve pathways are involved in the vestibulo-ocular reflex?

    <p>VIII and III, IV, and VI cranial nerves</p> Signup and view all the answers

    Which structure is primarily examined during testing of the palpebral reflex?

    <p>Medial canthus</p> Signup and view all the answers

    What factor determines the direction of lens dislocation in relation to the iris plane?

    <p>Anatomical position of zonular fibers</p> Signup and view all the answers

    Which of the following conditions is associated with oculoskeletal dysplasia in certain dog breeds?

    <p>Anterior lens luxation</p> Signup and view all the answers

    What is a common consequence of primary luxation of the lens?

    <p>Degeneration of zonular fibers</p> Signup and view all the answers

    Which category of retinal detachment is characterized by absolute vision loss?

    <p>Total retinal detachment</p> Signup and view all the answers

    In which age range do animals affected by rod-cone dysplasia typically become blind?

    <p>Between 1 and 3 years</p> Signup and view all the answers

    What primarily causes secondary lens luxation in ocular diseases?

    <p>Inflammatory zonulysis</p> Signup and view all the answers

    What is a key characteristic of geographic retinal detachment?

    <p>Localized areas of detachment</p> Signup and view all the answers

    Which of the following statements regarding the treatment of retinal detachment is accurate?

    <p>Surgical intervention is determined by the RD type</p> Signup and view all the answers

    What condition describes adhesion of the eyelid margins to each other?

    <p>Ankyloblepharon</p> Signup and view all the answers

    Which statement correctly describes distichiasis?

    <p>Abnormal growth of eyelashes from meibomian glands</p> Signup and view all the answers

    Which of the following is NOT a common sequelae of neonatal conjunctivitis?

    <p>Cataract formation</p> Signup and view all the answers

    What term is used to describe the condition where normal skin elements are found in an abnormal location?

    <p>Choristoma</p> Signup and view all the answers

    What is the primary treatment for entropion?

    <p>Surgical correction</p> Signup and view all the answers

    Which eyelid condition is characterized by an elevated, often pigmented mass bearing hairs?

    <p>Dermoid</p> Signup and view all the answers

    In treating neonatal conjunctivitis, which of the following is typically NOT a part of the treatment protocol?

    <p>Performing surgery to separate the lids</p> Signup and view all the answers

    What is a common cause of entropion?

    <p>Genetic predisposition</p> Signup and view all the answers

    What is a key action of adrenergic drugs in the treatment of glaucoma?

    <p>Reduce aqueous production</p> Signup and view all the answers

    Which of the following surgical procedures is aimed at reducing aqueous production in glaucoma treatment?

    <p>Transscleral cyclophotocoagulation</p> Signup and view all the answers

    Which condition is associated with severe pain and grossly elevated IOP?

    <p>Acute glaucoma</p> Signup and view all the answers

    What is a common consequence of glaucoma that affects vision?

    <p>Loss of vision</p> Signup and view all the answers

    Which type of glaucoma treatment involves chemically destroying the ciliary body?

    <p>Cyclocryosurgery</p> Signup and view all the answers

    In chronic glaucoma, what is the expected outcome of treatment with prostaglandin analogues?

    <p>Increased uveoscleral outflow</p> Signup and view all the answers

    Which clinical sign is often associated with acute glaucoma?

    <p>Fixed dilated pupil</p> Signup and view all the answers

    What is the primary function of adrenergic drugs classified as sympathomimetics in managing glaucoma?

    <p>Reduce aqueous production</p> Signup and view all the answers

    What is the primary cause of keratoconjunctivitis sicca (KCS)?

    <p>Immune-mediated destruction of the tear-producing glands</p> Signup and view all the answers

    Which pathogen is most commonly associated with feline conjunctivitis?

    <p>Feline herpesvirus 1 (FHV-1)</p> Signup and view all the answers

    What is a consequence of loss of epithelial or endothelial layers in the cornea?

    <p>Fluid accumulation leading to edema</p> Signup and view all the answers

    What is a possible effect of chronic corneal irritation?

    <p>Pigmentation of the cornea</p> Signup and view all the answers

    Which of the following conditions can result from iatrogenic excision of the nictitans gland?

    <p>Keratoconjunctivitis sicca (dry eye)</p> Signup and view all the answers

    Which condition is characterized by inflammation of both the cornea and conjunctiva due to low aqueous tear film components?

    <p>Keratoconjunctivitis sicca</p> Signup and view all the answers

    What is a definitive feature of a normal cornea in terms of vascularity?

    <p>Absence of blood vessels</p> Signup and view all the answers

    What role do environmental irritants, such as chemicals and dust, play in conjunctivitis?

    <p>They lead to persistent keratoconjunctivitis</p> Signup and view all the answers

    What is a common cause of papilledema in animals?

    <p>Neoplasia of the optic nerve</p> Signup and view all the answers

    Which of the following correctly describes the process of light transmission through the visual pathway?

    <p>Photons hit the retina before being relayed along the optic nerve</p> Signup and view all the answers

    In cases of optic neuritis, what is typically observed in the affected eye(s)?

    <p>Blindness with no pupillary light reflexes</p> Signup and view all the answers

    Which of the following disorders is caused by a congenital malformation of the optic nerve?

    <p>Optic nerve hypoplasia</p> Signup and view all the answers

    What is a potential consequence of vitamin A deficiency in steers regarding visual function?

    <p>It can lead to reduced pupillary light reflexes</p> Signup and view all the answers

    What role does the lateral geniculate nucleus play in the visual pathway?

    <p>It processes visual information from the retina</p> Signup and view all the answers

    Which statement is true regarding the pupillary light reflex?

    <p>It is not a reliable indicator of retinal function</p> Signup and view all the answers

    In the context of ocular motility, what function is NOT primarily generated by positional changes of the head?

    <p>Pupillary reflexes</p> Signup and view all the answers

    Which of the following is a likely cause of optic atrophy?

    <p>Post-inflammatory disease</p> Signup and view all the answers

    What characterizes the efferent arm in PLR (pupillary light reflex) testing?

    <p>No vision loss; direct or consensual deficit present</p> Signup and view all the answers

    Which reflex indicates some function in the retina and optic nerve despite not confirming vision?

    <p>Dazzle reflex</p> Signup and view all the answers

    Which statement is true regarding the menace response in an animal?

    <p>It is often absent in young animals.</p> Signup and view all the answers

    What is the primary technique used for assessing the palpebral reflex?

    <p>Evaluating blink response at the canthus</p> Signup and view all the answers

    Which of the following reflexes involves the trigeminal and facial nerves?

    <p>Corneal reflex</p> Signup and view all the answers

    In the context of unilateral optic issues, which condition is indicated by having vision loss but no PLR deficit?

    <p>Cortical lesion</p> Signup and view all the answers

    What is demonstrated by the vestibulo-ocular reflex?

    <p>Coordination of eye movements with head movements</p> Signup and view all the answers

    What is the maximum frequency for administering topical atropine 1% drops to dilate the pupil?

    <p>Four times daily</p> Signup and view all the answers

    What is the preferred surgical technique for treating deep ulcers or descemetoceles?

    <p>Conjunctival pedicle flap</p> Signup and view all the answers

    What condition is commonly associated with herpesvirus keratitis in cats?

    <p>Bilateral disease</p> Signup and view all the answers

    Which of the following is a common treatment for herpesvirus keratitis?

    <p>Topical antiviral medication</p> Signup and view all the answers

    What is a potential outcome for a dog with deep ulcers if not treated properly?

    <p>Perforation of the cornea</p> Signup and view all the answers

    Which of the following signs is associated with nonulcerative keratitis?

    <p>Vascularization across the cornea</p> Signup and view all the answers

    Which breed is most commonly associated with chronic superficial keratitis (pannus)?

    <p>German shepherd</p> Signup and view all the answers

    What symptom is often NOT observed in herpesvirus keratitis?

    <p>Severe pain</p> Signup and view all the answers

    What is the primary purpose of the outer oily layer in the tear film?

    <p>To prevent tear evaporation</p> Signup and view all the answers

    Which statement regarding the Schirmer tear test I (STTI) is correct?

    <p>Normal results range from 15 to 25 mm/minute.</p> Signup and view all the answers

    What anatomical structure contributes to the aqueous portion of tears?

    <p>Nictitans gland</p> Signup and view all the answers

    During the Schirmer tear test II, what should be done before the test?

    <p>Administer topical anesthetic to the cornea</p> Signup and view all the answers

    What is the primary role of the eyelids in ocular anatomy?

    <p>Protect the ocular globe</p> Signup and view all the answers

    Which component of the tear film is produced by conjunctival goblet cells?

    <p>Inner mucoid layer</p> Signup and view all the answers

    Where do tears primarily drain from the eye?

    <p>To the nasolacrimal duct</p> Signup and view all the answers

    What distinguishes the aqueous layer of the tear film from the others?

    <p>It contains antimicrobial proteins.</p> Signup and view all the answers

    What clinical sign is indicated by the presence of inflammatory cells in the anterior chamber of the eye?

    <p>Cell</p> Signup and view all the answers

    Which breed is NOT listed as having a predisposition for certain T-lymphocyte related conditions?

    <p>Labrador retriever</p> Signup and view all the answers

    What condition is described as a 360-degree circumferential posterior synechia resulting in pupillary block glaucoma?

    <p>Iris bombe</p> Signup and view all the answers

    Which of the following is the most common primary intraocular tumor in dogs?

    <p>Uveal melanoma</p> Signup and view all the answers

    What type of inflammatory debris is represented by keratic precipitates on the corneal endothelium?

    <p>Aggregates of cells and inflammatory debris</p> Signup and view all the answers

    Which clinical sign refers to the presence of pus in the anterior chamber?

    <p>Hypopyon</p> Signup and view all the answers

    Which of the following agents is associated with feline uveitis?

    <p>Viral agents</p> Signup and view all the answers

    What potential cause of equine recurrent uveitis (moonblindness) is linked to a bacterial infection?

    <p>Leptospirosis</p> Signup and view all the answers

    Which of the following describes the main physiological disruption in keratoconjunctivitis sicca?

    <p>Low aqueous component of the tear film</p> Signup and view all the answers

    Which of these is NOT caused by chronic corneal irritation?

    <p>Acidification of the tear film</p> Signup and view all the answers

    Which herpesvirus is primarily linked to feline conjunctivitis?

    <p>Feline herpesvirus 1 (FHV-1)</p> Signup and view all the answers

    What is the most common underlying cause of immune-mediated destruction of tear-producing glands?

    <p>Immune-mediated conditions</p> Signup and view all the answers

    Which structure serves as a supporting framework in the anatomy of the nictitating membrane?

    <p>T-shaped cartilage</p> Signup and view all the answers

    Feline conjunctivitis caused by Chlamydophila felis is typically treated with which medication?

    <p>Doxycycline</p> Signup and view all the answers

    Which pathological change in the cornea is characterized by the loss of its normal transparency due to fluid accumulation?

    <p>Edema</p> Signup and view all the answers

    What constitutes a common iatrogenic cause of keratoconjunctivitis sicca?

    <p>Excision of the nictitans gland</p> Signup and view all the answers

    Which layer of the eye is most vascular and includes the tapetum?

    <p>Choroid</p> Signup and view all the answers

    What characterizes retinitis-chorioretinitis in its active state?

    <p>Dull gray area with indistinct margins</p> Signup and view all the answers

    Which congenital anomaly is characterized by choroidal hypoplasia lateral to the optic disc?

    <p>Collie eye anomaly</p> Signup and view all the answers

    Which condition can lead to retinal hemorrhage due to coagulopathy?

    <p>Thrombocytopenia</p> Signup and view all the answers

    What is a potential cause of retinal detachment mentioned in conjunction with congenital issues?

    <p>Intraocular hemorrhage</p> Signup and view all the answers

    Which cranial nerve is responsible for carrying axons for vision?

    <p>CN II optic</p> Signup and view all the answers

    Which of the following is least likely to lead to retinal degeneration as mentioned in the provided content?

    <p>Nutritional deficiencies</p> Signup and view all the answers

    Which disease process can contribute to hyperreflectivity of the tapetal fundus?

    <p>Toxoplasmosis</p> Signup and view all the answers

    Study Notes

    Applanation Tonometers

    • Applanation tonometers measure intraocular pressure (IOP) by flattening a specific area of the cornea.
    • The Tonopen is the most commonly used applanation tonometer.

    Orbital Disease Conditions

    • Abcesses and cellulitis: Characterized by acute onset unilateral exophthalmos, pain when opening the mouth, and possible causes include trauma, foreign body, infection, and tooth-root abscess.
    • Orbital neoplasia: Gradual onset, slowly progressive exophthalmos, usually nonpainful when manipulating the mouth, and 90% are malignant.

    Eyelid Abnormalities

    • Agenesis (coloboma): Congenital defect, more common in cats and horses, characterized by the failure of the upper temporal eyelid to develop.
    • Ankyloblepharon: Adhesion of the eyelid margins to each other.
    • Dermoid: Choristoma (normal tissue in an abnormal location).
    • Entropion: Inversion of the eyelid margin, leading to secondary trichiasis (hairs rubbing on the cornea).
    • Ectropion: Eversion of the eyelid margin.
    • Distichiasis: Cilia arise from meibomian gland openings.
    • Ectopic cilia: Hair erupts through the palpebral conjunctiva.
    • Trichiasis: Hair in normal location but misdirected toward the globe.

    Blepharitis

    • Inflammation of the eyelids.
    • Bacterial Blepharitis: Most commonly caused by Staphylococcus intermedius.
    • Parasitic Blepharitis: Mites, such as Demodex or Sarcoptes in young dogs, Notoedres in cats, face flies and habronemiasis in horses.

    Neoplastic Eyelid Diseases

    • Canine: Meibomian gland adenoma is the most common benign tumor.
    • Feline: Malignant tumors are more common.
    • Congenital Abnormalities: Dermoid (choristoma) is a normal skin element found in an abnormal location.

    Neonatal Disease

    • Neonatal conjunctivitis (ophthalmia neonatorum): Infection before lid separation, often bacterial in puppies and viral or chlamydial in kittens.

    Conjunctivitis

    • Canine conjunctivitis: Bacterial conjunctivitis is rare.
    • Secondary causes of conjunctivitis: Conformational lid abnormalities, spread of infection from elsewhere.

    Corneal Ulcers

    • Epithelial corneal ulcer: Superficial, often accompanied by pain.
    • Indolent ulcers: Failure of epithelium to adhere to the basement membrane, common in dogs and cats.
    • Midstromal corneal ulcer: Potentially more serious, often caused by bacterial sepsis, particularly in neonates.
    • Fungal keratitis: Common in horses.
    • Deep corneal ulcer: Can affect the Descemet membrane and lead to corneal perforation.

    Glaucoma

    • Pathology: Impaired aqueous humor outflow system, elevated pressure within the eye, damages the axoplasmic flow in the optic nerve head leading to retinal degeneration and vision loss.
    • Anatomy and physiology: Aqueous humor production occurs in the nonpigmented ciliary body epithelium.
    • Treatment: Osmotic diuretics, carbonic anhydrase inhibitors, laser trabeculoplasty, surgical procedures such as filtration surgery.

    Horner Syndrome

    • Definition: Loss of sympathetic innervation to the eye.
    • Anatomy: Three components: central neuron, preganglionic neuron, postganglionic neuron.
    • Signs: Miosis, ptosis, enophthalmos, protrusion of nictitans.
    • Localization of the lesion: clinical signs and pharmacologic testing.

    Optic Nerve Atrophy

    • Atrophy of the optic nerve, often a consequence of glaucoma.
    • May be diagnosed by an ophthalmoscope.

    Other Important Points

    • The text mentions that glaucoma is a leading cause of blindness in middle-aged dogs.
    • It also mentions that Horner syndrome is often idiopathic in dogs and cats.
    • The text provides a list of supplemental reading resources for further information.

    Applanation Tonometry

    • Applanation tonometers measure the pressure needed to flatten a specific area of the corneal surface.
    • This pressure is proportional to intraocular pressure (IOP).
    • The Tonopen is the most commonly used applanation tonometer.

    Orbital Conditions

    • Orbital abscesses and cellulitis present with acute onset unilateral exophthalmos.

    • Symptoms include pain when opening the mouth, which can be caused by trauma, foreign bodies, infections (fungal, parasitic, tooth-root abscess, sinus infection), and inflammation of the zygomatic salivary gland.

    • Diagnostics include complete blood cell count (CBC), serum chemistry, orbital ultrasound, dental examination with or without radiographs, and fine needle aspiration (FNA) through oral mucosa behind the last molar.

    • Treatment includes draining the abscess and systemic antibiotics.

    • Orbital neoplasia presents with gradual onset, slowly progressive exophthalmos, and is usually nonpainful when manipulating the mouth.

    • Older animals are more likely to be affected, and 90% of cases are malignant.

    • Diagnostics include ultrasound and orbital computed tomography.

    Eyelid Abnormalities

    • Agenesis: A congenital defect in cats and horses where the upper temporal eyelid fails to develop.

    • Ankyloblepharon: Adhesion of the eyelid margins to each other.

    • Dermoid: A choristoma – normal tissue found in an abnormal location.

    • Entropion: Inversion of the eyelid margin, resulting in secondary trichiasis.

    • Ectropion: Eversion of the eyelid margin.

    • Distichiasis: Cilia arise from meibomian gland openings.

    • Ectopic cilia: Hair erupts through the palpebral conjunctiva.

    • Trichiasis: Hair in its normal location is misdirected towards the globe.

    Blepharitis

    • Inflammation of the eyelids
    • Bacterial blepharitis is most commonly caused by Staphylococcus intermedius.
    • Parasitic blepharitis can be caused by mites (e.g., Demodex, Sarcoptes) and other parasites.

    Neoplastic Eyelid Diseases

    • Canine: Meibomian gland adenoma is the most common benign eyelid tumor.
    • Feline: Dermoid (choristoma) is a common congenital abnormality.

    Neonatal Conjunctivitis (Ophthalmia Neonatorum)

    • Infection before lid separation is common.
    • Bacterial infections are common in puppies, while viral or chlamydial infections are common in kittens.
    • Treatment involves separating the lids, flushing with sterile saline, and applying a broad-spectrum antibiotic ointment.
    • Common sequelae include symblepharon (conjunctival adhesion), corneal perforation, fibrosis, and blindness.

    Conjunctivitis

    • Canine Conjunctivitis: Bacterial conjunctivitis is rare in dogs.
    • Secondary causes of canine conjunctivitis can include lid abnormalities, spread of infection from other areas, tear film abnormalities, and irritants.
    • Feline Conjunctivitis: Feline herpesvirus 1 (FHV-1) is the most common cause. Other causes include Chlamydophila felis (treated with tetracycline or doxycycline) and Mycoplasma felis (opportunistic, treated with topical tetracycline).

    Nictitating Membrane Anatomy

    • The nictitating membrane has a T-shaped cartilage and a nictitans gland at its base.

    Lens Abnormalities

    • Cataracts: A solid opacity of the lens with absence of a tapetal reflection.

    • Intumesent: The lens has imbibed water and is swollen.

    • Hypermature: Liquefaction of the lens cortex begins and the cortex begins to clear.

    • Morgagnian: Liquefaction of the cortex leaves a nuclear remnant that sinks.

    • Location within the lens:

      • Capsular: Opacity confined to the lens capsule.
      • Subcapsular: Most of the opacity involves the cortex directly beneath the lens capsule.
      • Cortical: Opacity of the lens cortex.
      • Nuclear: Opacity primarily in the center of the lens (nucleus).
      • Equatorial: Opacity is primarily in the area of the lens equator.
      • Polar and axial: Within the pupillary axis.

    Causes of Cataracts

    • Heredity
    • Age-related
    • Diabetes mellitus
    • Trauma
    • Uveitis
    • Secondary to retinal degeneration
    • Senile
    • Nutritional deficiencies
    • Electric shock
    • Radiation exposure
    • Toxic agents

    Treatment of Cataracts

    • Cataract surgery: Intracapsular lens extraction

    Abnormalities of Zonular Fibers (Lens Displacement)

    • Degree of dislocation:

      • Subluxation: Lens remains in the patellar fossa behind the iris.
      • Luxation: Complete displacement of the lens from the patellar fossa.

    • Direction of dislocation:

      • Anterior: Lens anterior to the plane of the iris (in the anterior chamber).
      • Posterior: Lens in the vitreous cavity.

    • Causes of lens dislocation:

      • Primary luxation: Degeneration of lens zonular fibers.
      • Secondary to ocular disease: Iridocyclitis, chronic glaucoma or buphthalmos, cataracts.

    Vitreous Abnormalities

    • The vitreous humour can be affected by inflammation, hemorrhage, and detachment.

    Fundus Abnormalities

    • Retinal detachment: Separation of the retina from the underlying choroid.
    • Retinal dysplasia (RD): Abnormal development of the retina, ranging in severity from minimal to severe.
      • Multifocal RD
      • Geographic RD
      • Total RD
    • Acquired inherited abnormalities: Progressive retinal atrophy (PRA) is bilateral and progressive, leading to eventual blindness.
      • Rod-cone dysplasia (rcd): Animals are typically blind by between 1 and 3 years of age.
      • Rod-cone degeneration: Onset is at 2 to 4 years of age, and blindness occurs sometime later.

    Canaliculi

    • Canaliculi are small ducts that drain tears from the puncta to the lacrimal sac.

    Conjunctival Sac

    • The conjunctival sac is the space between the eyelids and the eyeball.

    Nasolacrimal Duct

    • The nasolacrimal duct empties into the nose at the nasal ostium.

    Globe Wall Tunics

    • The outer tunics of the globe are made up of the cornea and the sclera.
    • The uveal tract, composed of the iris, ciliary body, and choroid, forms the middle vascular coat.
    • The retina, including the retinal pigment epithelium and neurosensory retina, is the inner neuroepithelial layer.

    Orbital Abscesses and Cellulitis

    • They cause acute onset, unilateral exophthalmos and pain when opening the mouth.
    • Other possible causes include: trauma, foreign body, fungal or parasitic infections, tooth-root abscess, sinus infection, and inflammation of the zygomatic salivary gland (often associated with a mucocele).

    Orbital Neoplasia

    • It typically presents with gradual onset, slowly progressive exophthalmos.
    • It's usually nonpainful when manipulating the mouth.
    • It can lead to enophthalmos in some cases.
    • 90% of cases are malignant.

    Lens Dislocation

    • Direction of dislocation can be anterior or posterior
    • Anterior dislocation occurs when the lens is anterior to the plane of the iris and may cause corneal edema
    • Posterior dislocation involves the lens being located in the vitreous cavity.
    • Primary luxation is due to degeneration of lens zonular fibers and occurs more often in terriers.
    • Secondary luxation occurs as a result of ocular disease.

    Vitreous

    • The outermost layer of the vitreous is the sclera.
    • The middle layer of the vitreous contains the choroid, which is highly vascular and includes the tapetum.
    • The innermost layer of the vitreous is the retina, consisting of the retinal pigment epithelium and the neurosensory retina.

    Congenital Anomalies

    • Collie eye anomaly is a choroidal hypoplasia lateral to the optic disc that can cause coloboma, retinal detachment, hemorrhage, and retinal vasculature tortuosity.
    • Retinal hemorrhage can be caused by thrombocytopenia, thrombocytopathy, coagulopathy, or postganglionic hemorrhage.

    Horner Syndrome

    • It is characterized by loss of sympathetic innervation to the eye.
    • Signs include miosis, ptosis, enophthalmos, and protrusion of the nictitans.

    Cranial Nerves with Ophthalmic Implications

    • CN II (optic): Carries axons for vision and controls the pupillary light reflex (PLR).
    • CN III (oculomotor): Motor to the dorsal, medial, and ventral rectus muscles and responsible for pupillary dilation
    • CN IV (trochlear): Motor to the dorsal oblique muscles and responsible for the eye’s ability to look down and out.
    • CN VI (abducens): Motor to the lateral rectus muscle and responsible for the eye’s ability to look out.
    • Horner syndrome is often idiopathic in dogs and cats.

    Blepharitis

    • Bacterial blepharitis is commonly caused by Staphylococcus intermedius.
    • Parasitic blepharitis can be caused by mites, fleas, or habronemiasis.
    • Demodex, Sarcoptes, and Notoedres are some common mites that affect eyelids.

    Neoplastic Eyelid Diseases

    • Meibomian gland adenoma is a common benign neoplasm in dogs.
    • Malignant neoplasms in felines can result in abnormal retinal development and vary in severity from lesions that have no effect on vision to blindness.

    Retinal Detachment (RD)

    • There are three categories of RD: multifocal RD, geographic RD, and total RD.
    • In Labrador retrievers and Samoyeds, RD is associated with oculoskeletal dysplasia, a dominant trait with incomplete penetrance characterized by skeletal abnormalities and shortened legs with joint deformities.

    Acquired Inherited Abnormalities

    • Progressive retinal atrophy (PRA) is a bilateral and progressive condition that leads to blindness.
    • Rod-cone dysplasia (rcd) typically causes blindness by 1-3 years of age.
    • Rod-cone degeneration develops around 2-4 years of age and results in blindness later in life.

    Retinitis-Chorioretinitis

    • Active retinitis-chorioretinitis is characterized by a dull gray area with indistinct margins between normal and affected retina.
    • Inactive retinitis-chorioretinitis results in hyperreflectivity of the tapetal fundus and hyperpigmentation of the tapetal fundus.
    • Causes include mycoses, bacteria, viruses, parasites, and hypertension.

    Neuro-Ophthalmology

    • Pharmacologic testing helps differentiate between preganglionic and postganglionic Horner syndrome
    • 10% phenylephrine ophthalmic solution can be used to evaluate for denervation hypersensitivity and confirm the presence of Horner syndrome.

    Tear Production and Tear Gland Issues

    • Cyclosporine can reduce immune destruction of tear producing glands.
    • Oral pilocarpine can stimulate tear production.
    • Parotid duct transposition involves moving the parotid duct so that it opens into the lower conjunctival fornix.

    Investigation of Corneal Ulcers

    • A fluorescein stain can be used to show the presence and extent of a corneal ulcer.
    • The depth of the ulcer should be noted, with special care to note that Descemet's membrane does not stain with fluorescein.
    • A swab should be taken from the edge of the ulcer crater for culture to determine if it is bacterial or fungal (in some cases).
    • A smear from the edge of the ulcer should also be taken for cytology.

    Types of Corneal Ulcers

    • Superficial corneal ulcers are typically treated with topical atropine 1% drops to dilate the pupil.
    • Superficial ulcers should be monitored closely and treated with broad spectrum antibiotics.
    • If a corneal ulcer is infected, antibiotics should be given frequently (initially every 2 hours).
    • Superficial corneal ulcers typically heal within 3 to 5 days, but if they haven't resolved within that time frame, further investigation is needed.
    • Systemic nonsteroidal anti-inflammatory drugs (NSAIDs) can be given to suppress uveitis in cases of corneal ulcers.
    • Deep ulcers or descemetoceles are considered emergencies because they can perforate.
    • Deep ulcers typically require surgical repair.
    • A conjunctival pedicle flap is a preferred technique for surgical repair as it provides a blood supply to the defect for healing and physical protection to seal the defect.
    • If surrounding cornea is healthy and not infected or melting, a corneoscleral transposition procedure can be performed.

    Herpesvirus Keratitis

    • Herpesvirus keratitis (FHV-1) is common in cats.
    • Conjunctivitis with or without corneal ulcers often accompany herpesvirus keratitis.
    • Symblepharon conjunctival adhesions are common sequelae of herpesvirus keratitis.
    • Treatment for herpesvirus keratitis includes topical antiviral medication (idoxuridine or trifluridine) and topical corticosteroids.

    Glaucoma

    • Glaucoma is caused by impairment of the aqueous humor outflow system, leading to elevated pressure within the eye.
    • High intraocular pressure damages the optic nerve head, resulting in retinal degeneration and vision loss.
    • Glaucoma is a leading cause of blindness in middle-aged dogs.

    Aqueous Humor Outflow

    • The aqueous humor outflow system is comprised of two pathways: corneoscleral outflow (conventional outflow) and uveoscleral outflow (nonconventional outflow).
    • Corneoscleral outflow is the primary pathway in most dogs and cats.
    • Uveoscleral outflow is a secondary pathway that is less active than corneoscleral outflow.

    Classifications of Glaucoma

    • Primary glaucoma is common in dogs and often involves an abnormal formation of the iridocorneal angle (goniodysgenesis).
    • Secondary glaucoma is a result of disease processes that interfere with aqueous humor outflow.
    • Some of the causes of secondary glaucoma include primary lens luxation, abnormal retinal development, and vitreous detachment.

    Treatment of Glaucoma

    • Treatment options for glaucoma can be medical or surgical.
    • Medical treatment options include osmotic diuretics, carbonic anhydrase inhibitors (CAIs), miotics, and sympatholytic drugs (-blockers).
    • Osmotic diuretics (mannitol IV 20%, glycerol 50% oral solution) quickly dehydrate the vitreous humor and lower eye pressure but should be used with caution due to their potential side effects (hypovolemia, pulmonary edema, renal failure).
    • Carbonic anhydrase inhibitors (methazolamide, acetazolamide, dorzolamide hydrochloride 2% topical) decrease aqueous humor production by inhibiting the formation of bicarbonate ions, but can cause side effects such as hypovolemia, metabolic acidosis, and hypokalemia.
    • Miotics (pilocarpine 2% solution, phospholine iodide) applied topically can increase aqueous humor outflow.
    • Sympatholytic drugs (-blockers) (timolol maleate) decrease aqueous humor production.

    Lens Luxation

    • Lens luxation is a condition in which the lens of the eye dislocates or moves from its normal position.
    • There are two directions of lens dislocation—anterior and posterior.
    • Anterior lens luxation occurs when the lens is located anterior to the plane of the iris (in the anterior chamber).
    • Posterior lens luxation occurs when the lens is located in the vitreous cavity.
    • The causes of lens luxation can be primary or secondary.
    • Primary lens luxation results from degeneration of lens zonular fibers and is more common in certain breeds, such as terriers.
    • Secondary lens luxation can result from ocular diseases such as iridocyclitis (inflammatory zonulysis), chronic glaucoma, or buphthalmos.

    Retinal Detachment (RD)

    • RD is a condition involving detachment of the retina, leading to blindness.
    • There are three categories of RD: multifocal RD, geographic RD, and total Rd.
    • In Labrador retrievers and Samoyeds, RD is commonly associated with skeletal dysplasia, a syndrome called oculoskeletal dysplasia.
    • Oculoskeletal dysplasia results in shortened legs and joint deformities and is a dominant and incompletely penetrant genetic trait.
    • Acquired inherited abnormalities, such as progressive retinal atrophy (PRA), are bilateral and progressive disorders that lead to blindness.
    • Examples of PRA include Rod-cone dysplasia (rcd) and Rod-cone degeneration.

    Retinal Detachment with Skeletal Dysplasia

    • Retinal detachment in dogs can be associated with skeletal dysplasia syndromes in dogs.
    • Osculockeletal dysplasia includes shortened legs or joint deformities.
    • Oculoskeletal dysplasia is most common in Labrador retrievers and Samoyeds, resulting from a dominant genetic inheritance with incomplete penetrance.
    • Oculoskeletal dysplasia in these breeds is associated with retinal detachment.

    Congenital Abnormalities

    • Agenesis (coloboma): A congenital defect where normal elements of skin are in an abnormal location.
      • Cats: Upper temporal eyelid (lateral 1/3 to 2/3) fails to develop.
      • Horses: Absence of eyelids results in secondary trichiasis and exposure keratoconjunctivitis.
    • Ankyloblepharon: Adhesion of the eyelid margins to each other.
    • Dermoid: A choristoma (normal tissue in an abnormal location).
      • Aberrant dermis affecting conjunctiva and/or cornea:
        • Sometimes also affects eyelids.
        • Appears as an elevated, often pigmented mass, usually bearing hairs.
        • Surgical excision is curative.
    • Entropion: Inversion of the eyelid margin (usually results in secondary trichiasis).
      • Causes hairs to rub on cornea (secondary trichiasis).
      • Correct surgically with a modified Hotz-Celsus excision.
    • Ectropion: Eversion of the eyelid margin.

    Eyelash Abnormalities

    • Distichiasis: Cilia arise from meibomian gland openings
      • Causes:
        • Conformational lid abnormalities (e.g., entropion, ectropion, trichiasis, lid tumors)
        • Spread of infection from elsewhere (e.g., skin, ears, lips)
        • Tear film abnormalities: Keratoconjunctivitis sicca (dry eye)
        • Irritants: Chemicals, dust

    Neonatal Disease- Neonatal Conjunctivitis (ophthalmia neonatorum)

    • Infection before lid separation; often bacterial in puppies and viral or chlamydial in kittens.
    • Treatment:
      • Separate lids, flush with sterile saline, apply broad-spectrum antibiotic ointment four times daily in dogs, tetracycline in kittens.
    • Sequelae: Symblepharon (conjunctival adhesion to adjacent tissues), corneal perforation, fibrosis, blindness

    Conjunctivitis

    • Canine Conjunctivitis:
      • Bacterial: Rare
      • Secondary Causes:
        • Conformational lid abnormalities (e.g., entropion, ectropion, trichiasis, lid tumors)
        • Spread of infection from elsewhere (e.g., skin, ears, lips)
        • Tear film abnormalities: Keratoconjunctivitis sicca (dry eye)
        • Irritants: Chemicals, dust
      • Viral: Canine distemper
      • Allergic or hypersensitivity
    • Feline Conjunctivitis:
      • Feline herpesvirus 1 (FHV-1) is the most common cause.
      • Chlamydophila felis may cause conjunctivitis. Treat with tetracycline or doxycycline.
      • Mycoplasma felis: Opportunistic. Treat with topical tetracycline.

    Examining the eye

    • Schirmer tear test I (STTI) measures tear production.

      • Measures basal and stimulated tear production.
      • Preformed before any drops or topical anesthetic.
      • Normal tear production: 15-25 mm/minute.
      • Reduced tear production: < 10 mm/minute
      • Dry eye: < 5 mm/minute

    • Schirmer tear test II measures basal tear production.

      • Performed after anesthetizing the cornea.
      • Excess fluid is removed from skin, ears, and lips.

    • Corneal epithelium features

      • Outermost layer, protects the eye
      • Does not take up fluorescein stain
      • Can be affected by edema and vascularization

    • Causes of feline conjunctivitis

      • Feline herpesvirus 1 (FHV-1) is the most common cause of feline conjunctivitis.
      • Chlamydophila felis can cause conjunctivitis.
      • Mycoplasma felis is an opportunistic infection that can cause conjunctivitis.

    Disorders of the nictitating membrane

    • Nictitating membrane aka third eyelid (nictitans)
      • T-shaped cartilage skeleton
      • Nictitans gland produces the aqueous portion of tears
      • Protects the globe
      • Distributes the tear film
      • Produces the lipid layer of tears
      • Drains the tear film

    Keratitis

    • Keratitis: inflammation of the cornea

    • Causes

      • Edema: Fluid accumulation in the cornea caused by damage to the epithelial or endothelial layers.
      • Vascularization: Abnormal blood vessel growth in the cornea.
      • Pigmentation: Occurs as a result of chronic corneal irritation.

    • Keratoconjunctivitis sicca (KCS; dry eye): inflammation of the cornea and conjunctiva due to low aqueous component of the tear film.

    • Causes of KCS:*

      • Immune-mediated destruction of tear-producing glands (most common cause).
      • Congenital gland aplasia (unilateral or bilateral).
      • Iatrogenic (excision of nictitans gland).

    Corneal Ulcers

    • Corneal ulcers are erosions in the cornea.

    • Causes

      • Trauma
      • Infectious agents (bacteria, viruses, fungi)
      • Dry eye
      • Immune-mediated disease

    • Clinical signs of a corneal ulcer

      • Pain
      • Squinting
      • Blepharospasm (eyelid spasms)
      • Discharge
      • Cloudiness of the cornea

    • Treatment of corneal ulcers

      • Topical antibiotics
      • Topical anti-inflammatory agents (corticosteroids)
      • Surgical debridement
      • Therapeutic lenses

    Other corneal conditions

    • Deep ulcers or descemetoceles require surgical repair.

      • Conjunctival pedicle flap: Preferred surgical technique; provides blood supply and physical protection to the affected area.
      • Corneoscleral transposition: Used if the surrounding cornea is healthy.

    • Herpesvirus keratitis (FHV-1): Common in cats.

      • Clinical signs: conjunctivitis with or without corneal ulcer, symblepharon (conjunctival adhesions).
      • Treatment: Topical antiviral medication, topical corticosteroids.

    Uveitis

    • Uveitis: Inflammation of the uveal tract (iris, ciliary body, choroid).

    • Clinical signs:

      • Pain
      • Redness
      • Swelling
      • Cloudiness of the eye

    • Common causes of uveitis in dogs:

      • Immune-mediated disease
      • Infectious agents (bacteria, viruses, fungi)
      • Trauma
      • Intraocular tumors

    • Cataracts: Opacities in the lens of the eye.

    • Causes

      • Age
      • Trauma
      • Diabetes mellitus
      • Certain medications

    • Treatment of cataracts:

      • Surgical removal
      • Lens implants

    Retinal Disease/ Disorders

    • Retina: Innermost layer of the eye, responsible for light reception

    • Retinal disease may lead to blindness.

    • Clinical signs:

      • Loss of vision
      • Changes in pupil size
      • Difficulty with night vision

    • Causes

      • Trauma
      • Diabetes mellitus
      • High blood pressure
      • Degenerative diseases
      • Genetic disorders

    • Treatment

      • Laser surgery
      • Cryotherapy
      • Photocoagulation

    Neuro-Ophthalmology: Implications for cranial nerves

    • CN II is responsible for carrying axons for vision.
    • CN III controls motor functions of the iris.

    Intraocular tumors

    • Primary intraocular tumors are the most common tumors in the eye.
      • Uveal melanoma: Most common type of primary intraocular tumor in dogs.
    • ** Secondary intraocular tumors** are rare.
      • Lymphosarcoma: Most common type of secondary intraocular tumor.

    Equine recurrent uveitis (ERU)

    • ERU (equine recurrent uveitis) is characterized by recurrent inflammation of the uvea in horses.

    • Causes: Possible causes include Leptospirosis, Onchocerca cervicalis.

    • Clinical signs:

      • Pain
      • Redness
      • Decreased vision
      • Cloudiness of the eye

    • Treatment

      • Anti-inflammatory medications
      • Immunosuppressive therapy
      • Surgery

    Glaucoma

    • Glaucoma: An increase in intraocular pressure (IOP).

    • Causes

      • Decreased outflow of aqueous humor
      • Increased production of aqueous humor
      • Blockage of the drainage angle

    • Clinical signs

      • Pain
      • Redness
      • Cloudiness of the eye
      • Dilated pupil
      • Loss of vision

    • Treatment

      • Medications to reduce IOP
      • Laser surgery
      • Surgery to improve aqueous humor outflow

    Other disorders of the eye

    • Buphthalmos: Enlargement of the eye due to increased IOP.
    • Retinitis-chorioretinitis: Inflammation of the retina and choroid.
      • Clinical signs: Dull gray areas in the retina, hyperreflectivity of the tapetal fundus, hyperpigmentation of the tapetal fundus.
      • Causes: Mycoses, bacterial septicemia, viral diseases (distemper), toxoplasmosis, hypertension, neoplasia, parasitic migration.

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    Description

    Test your knowledge on applanation tonometers and various orbital diseases along with eyelid abnormalities commonly found in veterinary medicine. This quiz explores critical concepts and specific conditions affecting the eyes of animals. Perfect for veterinary students and practitioners alike!

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