Ophthalmology: Latent Squint and Heterophoria
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Questions and Answers

What characterizes latent squint (heterophoria)?

  • Eye deviation is apparent without binocular vision.
  • Only occurs in individuals over the age of 60.
  • It is a permanent condition with visible symptoms.
  • The eye remains straight due to binocular vision. (correct)

    • Which type of phoria involves an outward deviation of the eye?

  • Exophoria (correct)
  • Hypophoria
  • Esophoria
  • Hyperphoria

    • What is the primary purpose of the Cover-Uncover Test?

  • To measure the strength of extraocular muscles.
  • To assess the patient’s visual acuity.
  • To diagnose the specific type of heterophoria.
  • To identify any deviation when binocular vision is disrupted. (correct)

    • What does the Maddox rod test primarily measure?

    <p>The degree and direction of heterophoria.</p> Signup and view all the answers

    Which treatment option is typically used as a last resort for heterophoria?

    <p>Surgery to correct muscle imbalance.</p> Signup and view all the answers

    How prevalent is heterophoria in the general population?

    <p>70-80%</p> Signup and view all the answers

    Which of the following is NOT a type of heterophoria?

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

    In a decompensated case of heterophoria, what condition might manifest?

    <p>Manifest squint</p> Signup and view all the answers

    Which extra-ocular muscle primarily facilitates adduction?

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

    What primary action is performed by the inferior oblique muscle?

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

    According to Sherrington's Law, what happens when the lateral rectus contracts?

    <p>Medial rectus relaxes</p> Signup and view all the answers

    Which type of movement is defined as the movement of both eyes in the same direction?

    <p>Version movement</p> Signup and view all the answers

    In the prism-cover test, what is the general formula to determine the angle in degrees?

    <p>1½ Prism power (Diopter)</p> Signup and view all the answers

    Which of the following best describes the term 'vergence movement'?

    <p>Coordinated eye movement towards a target</p> Signup and view all the answers

    What is the primary role of agonist muscles in ocular motility?

    <p>To contract for the desired eye movement</p> Signup and view all the answers

    If the corneal light reflex is noted to be at the pupil margin, what does this indicate regarding angle of squint?

    <p>15 degrees</p> Signup and view all the answers

    Which of the following is NOT one of the classic symptoms of congenital glaucoma?

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

    What is the primary inherited pattern of primary congenital glaucoma?

    <p>Autosomal recessive</p> Signup and view all the answers

    Which of the following types of congenital glaucoma has the highest prevalence?

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

    What is a significant sign of congenital glaucoma seen in infancy?

    <p>Deep anterior chamber</p> Signup and view all the answers

    Which of the following statements about secondary congenital glaucoma is true?

    <p>It can be triggered by trauma.</p> Signup and view all the answers

    What is the most common type of glaucoma overall?

    <p>Primary open-angle glaucoma</p> Signup and view all the answers

    Which of the following is considered an early sign of congenital glaucoma?

    <p>Large globe</p> Signup and view all the answers

    What percentage of cases of primary congenital glaucoma manifest before the age of 6 months?

    <p>70%</p> Signup and view all the answers

    What is a common ocular manifestation associated with rheumatoid arthritis?

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

    Which of the following is a complication of Sjögren syndrome?

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

    What typical test is used to diagnose Sjögren syndrome?

    <p>Schirmer’s test</p> Signup and view all the answers

    Which demographic is most likely to be affected by sarcoidosis?

    <p>Females of African descent</p> Signup and view all the answers

    What is a primary symptom of multiple sclerosis?

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

    Which autoimmune condition is characterized by dryness of the mouth and eyes?

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

    Which of the following is NOT a treatment option for sarcoidosis?

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

    Which of the following joints is typically spared in rheumatoid arthritis?

    <p>Distal interphalangeal joints</p> Signup and view all the answers

    What is the primary treatment goal for amblyopia?

    <p>Occluding the normal eye</p> Signup and view all the answers

    Which type of strabismus involves a large constant alternating angle of deviation?

    <p>Infantile esotropia</p> Signup and view all the answers

    In the basic principles of squint surgery, what does recession imply?

    <p>Shifting the muscle insertion posteriorly</p> Signup and view all the answers

    What type of amblyopia develops when one eye is excluded from central cortical activity?

    <p>Stimulus deprivation amblyopia</p> Signup and view all the answers

    Which of the following is a rule for unilateral squint surgery involving exotropia?

    <p>MR resection for esotropia</p> Signup and view all the answers

    At what age does amblyopia typically not develop beyond?

    <p>6 years</p> Signup and view all the answers

    What is a characteristic feature of non-refractive exotropia?

    <p>Usually requires large surgical correction</p> Signup and view all the answers

    Which type of amblyopia occurs in children with lateral uncorrected errors?

    <p>Meridional amblyopia</p> Signup and view all the answers

    What is the duration of occlusion therapy to achieve optimal results for amblyopia?

    <p>Until visual acuity is fully developed</p> Signup and view all the answers

    Which type of squint surgery involves bilateral lateral rectus resection?

    <p>Alternating squint for esotropia</p> Signup and view all the answers

    Which condition is characterized by inflammation of all layers of the sclera?

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

    What is the most common cause of episcleritis?

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

    Which symptom is NOT commonly associated with scleritis?

    <p>Usually unilateral pain</p> Signup and view all the answers

    What type of episcleritis is most prevalent?

    <p>Simple diffuse episcleritis</p> Signup and view all the answers

    Which type of staphyloma involves bulging associated with keratitis and corneal perforation?

    <p>Corneal staphyloma (Anterior)</p> Signup and view all the answers

    Which condition is more dangerous and less common than episcleritis?

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

    Which of the following is a treatment option for scleritis?

    <p>Immunosuppressive drug in refractory cases</p> Signup and view all the answers

    Which extra-ocular muscle originates at the orbital apex?

    <p>Superior oblique muscle</p> Signup and view all the answers

    Which of the following best describes the characteristic of chronic uveitis?

    <p>Insidious onset and often asymptomatic.</p> Signup and view all the answers

    What symptom is commonly associated with acute anterior uveitis?

    <p>Rapid painful loss of vision.</p> Signup and view all the answers

    Which of the following is NOT a cause of acute anterior uveitis?

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

    What does the presence of aqueous flare indicate?

    <p>It indicates active inflammation.</p> Signup and view all the answers

    Which type of uveitis involves both the iris and ciliary body?

    <p>Anterior uveitis.</p> Signup and view all the answers

    How are keratic precipitates classified based on the type of uveitis?

    <p>Large for granulomatous and small for non-granulomatous.</p> Signup and view all the answers

    Which of the following is an example of a non-infectious cause of uveitis?

    <p>Ankylosing spondylitis.</p> Signup and view all the answers

    What is the typical duration of symptoms in acute uveitis?

    <p>6 weeks or less.</p> Signup and view all the answers

    Study Notes

    Latent Squint (Heterophoria)

    • Characterized by a tendency for the eye to deviate due to extraocular muscle (EOM) imbalance while being held straight by binocular vision.
    • Occurs in 70-80% of the population, with incidence increasing with age.
    • Causes include mild weakness in the EOM or errors of refraction.

    Types of Heterophoria

    • Exophoria: Tendency for eye to deviate outward.
    • Esophoria: Tendency for eye to deviate inward.
    • Hyperphoria: Tendency for eye to deviate upwards.
    • Hypophoria: Tendency for eye to deviate downwards.
    • Excyclophoria: Tendency for eye to roll outward.
    • Incyclophoria: Tendency for eye to roll inward.

    Symptoms

    • Most cases are compensated, showing no symptoms.
    • Decompensated cases might show manifest squint.

    Diagnosis

    • Cover-Uncover Test: Assessing eye for deviation by covering one eye to disrupt binocular vision.
    • Maddox Rod Test (Far): Evaluates how a red line appears when an eye is covered; deviation indicates heterophoria strength.
    • Maddox Wing Test (Near): Assesses vertical and horizontal phoria at a distance of 40 cm using prismatic lenses.

    Treatment

    • Minor errors may require no treatment.
    • Correct refractive errors.
    • Consider strengthening weak eye muscles; surgery is a last resort.

    Paralytic Squint

    • Occurs due to paralysis of one or more extraocular muscles, can be partial (paresis) or complete.

    Functions of Extra-Ocular Muscles

    • Horizontal Muscles: Lateral rectus (abduction), medial rectus (adduction).
    • Vertical Muscles: Superior rectus (elevation), inferior rectus (depression), superior oblique (intorsion), inferior oblique (extorsion).

    Ocular Motility Terms

    • Ductions: Monocular movements controlled by agonist and antagonist muscles.
      • Adduction: Movement in one direction.
      • Abduction: Movement in the opposite direction.
    • Version Movement: Simultaneous movement of both eyes in the same direction.
    • Vergence Movement: Coordinated eye movement, includes convergence (inward) and divergence (outward).

    Sherrington's Law

    • States that when one muscle contracts (agonist), the antagonist relaxes simultaneously.

    Angle of Squint Measurement

    • Corneal Light Reflex (Hirschberg Test): Uses light reflection to assess squint angle.
    • Prism-Cover Test: Measures angle deviation by determining how much a prism affects the squinting eye.

    Inflammation of the Sclera

    • Episcleritis: Inflammation of superficial sclera, more common, usually unilateral, associated with collagen diseases.
    • Scleritis: Inflammation of all scleral layers, can be bilateral, often seen in elderly females.

    Symptoms of Scleral Inflammation

    • Episcleritis: Painful not tender, presents with a red eye.
    • Scleritis: Painful and tender, red eye, may lead to complications like glaucoma and keratitis.

    Staphyloma

    • Bulging of sclera or cornea due to conditions such as keratitis or high intraocular pressure.
    • Types include anterior (corneal) and posterior staphyloma.

    Amblyopia

    • Defined as decreased visual acuity without correctable pathology.
    • Develops during critical visual development, primarily in children under 6 years of age.

    Treatment of Amblyopia

    • Occlusion therapy to encourage usage of the amblyopic eye.

    Congenital Glaucoma (Buphthalmos)

    • Caused by developmental anomalies in the anterior chamber angle, it usually manifests during the first 6 months of life.
    • Symptoms include lacrimation and photophobia; signs include large globe, corneal edema, and increased intraocular pressure.

    Strabismus

    • Types include refractive and non-refractive exotropia, often corrected surgically.
    • Can occur due to various underlying diseases.

    Autoimmune Diseases

    • Sjögren Syndrome: Autoimmune condition affecting lacrimal and salivary glands, presenting with dry mouth and eyes.
    • Rheumatoid Arthritis: Autoimmune disease causing symmetrical joint inflammation with ocular manifestations like scleritis and secondary Sjögren syndrome.
    • Sarcoidosis: Granulomatous inflammation affecting the eye, can lead to various uveitis types.

    Multiple Sclerosis

    • Demyelinating disease with ocular features like optic neuritis.
    • Typically presents in the 3rd-4th decades of life.

    Uveitis

    • Inflammation of the uveal tract; classified anatomically, clinically, and etiologically.
    • Acute anterior uveitis is common, caused by infections and autoimmune disorders, causing rapid painful loss of vision and photophobia.

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    Description

    Explore the condition of latent squint, or heterophoria, in this quiz. Understand its epidemiology, causes, and different types, including exophoria, esophoria, and hyperphoria. Test your knowledge on how this common eye condition affects the population.

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