Ophthalmology 2024 Past Paper PDF

Ophthalmology 2024 MICHAEL B. WHITEHEAD DHSC, PA-C PHAS 5312 PATHOPHYSIOLOGIC PROCESSES I  Objectives Module I ARCPA Instructional Objective Ophthalmology B2.02c 1. Review the structures and function of the eye....

Ophthalmology 2024 MICHAEL B. WHITEHEAD DHSC, PA-C PHAS 5312 PATHOPHYSIOLOGIC PROCESSES I  Objectives Module I ARCPA Instructional Objective Ophthalmology B2.02c 1. Review the structures and function of the eye. 2. Outline the molecular events of light perception by the retinal cells. 3. Describe the common structural defects impairing vision: hyperopia, presbyopia, myopia, astigmatism, amblyopia, and nystagmus. 4. Discuss how vitreous fluid forms and complications of imbalance in production and removal. 5. Explain how intraocular pressure may become elevated and how it may affect vision. 6. List common conditions of the cornea, lens, conjunctiva, and eyelids. 7. Describe retinal changes of diabetic retinopathy, hypertensive retinopathy, and macular degeneration.  Topics  Anatomy of the eye  Vitreous humor  Common conditions  Cornea  Lens  Conjunctiva  Eyelids  Changes from  Diabetic retinopathy  Hypertensive retinopathy  Macular degeneration  Anterior Chamber  Anterior border is the cornea  Lateral borders are trabecular meshwork  Posterior border is the iris  Posterior Chamber 5  Small chamber behind the iris (smaller than the anterior chamber)  Anterior border is the posterior iris  Posterior border is the lens  Contains the ciliary body  The ciliary body produces aqueous fluid which fills the posterior chamber and enters the anterior chamber through the pupil.  Vitreous Humor  Produced by cells of the ciliary body  Embryonic cells that degenerate post-birth  Fixed amount of fluid  Helps maintain shape of globe  Gel–like consistency  Changes with aging  Floaters  Retinal detachment  Retinal Cells & Light Perception  Retina is innermost layer  Cells convert light energy into 3D images  Only extension of the brain viewed from the outside  Extension of Optic nerve (CN II)  Light reaches photoreceptor cells>rods and cones>action potentials conveyed to the brain>optic chiasm>lateral geniculate nucleus>visual cortex  Development begins during 4th week of embryogenesis continues into the first year of life  Consumes a high amount of oxygen  Six different cell lines that divide into 10 layers  Cornea  Major refractive surface  Avascular  Aids transparency  Contributes to low incidence of graft rejection  Corneal Degenerations  Unilateral or bilateral – usually non-familial  Band keratopathies  Calcific band keratopathy  Ca deposits in the Bowman layer (anterior)  Actinic band keratopathy  Exposure to chronic levels of UV light  Keratoconus – progressive corneal thinning  Cornea changes shape – becomes conical  Associated with Down Syndrome, Marfan Syndrome, and atopic disorders  Corneal Dystrophies  Generally inherited  Fuchs Endothelial Dystrophy  Loss of endothelial cells  Edema and thickening of the stroma  Stromal Dystrophies  Stromal deposits create opacities  Loss of vision  Glaucoma  Distinctive changes in visual fields and cup of the optic nerve  Second leading cause of blindness  Elevated intraocular pressure (IOP)  Normal IOP 8-21 mmHg  Can have both primary and secondary causes  Some primary causes are genetic  Myocillin (MYOC) and optineurin (OPTN) genes  Open angle glaucoma  Flow of aqueous maintained  Change in resistance  Too much aqueous  Poor drainage system  More prevalent in patients of European or African descent  Closed angle glaucoma  Emergency condition  Rapid rise in IOP  Peripheral iris adheres to trabecular network  Blocks passage of aqueous humor  Occurs in patients with shallow anterior chambers  More prevalent in patients of Asian and Inuit descent  Risk factors  FH, 60+, female, hyperopia, medications, flaky deposits (pseudoexfoliation), race  Presentation Closed Angle Glaucoma  Symptoms:  Decreased vision  Halos around lights  Headache  Severe eye pain  Nausea and vomiting  Presentation Closed Angle Glaucoma  Signs:  Conjunctival redness  Corneal edema or cloudiness  A shallow anterior chamber  A mid-dilated pupil (4 to 6 mm) that reacts poorly to light Acute angle closure glaucoma  Lens  Closed epithelial system  Capsule (basement membrane) envelops the lens  Bathed by aqueous humor – circulates via pupil from posterior to anterior chamber  Cataracts  Opacification of the intraocular lens  Most common worldwide cause of reversible blindness  50% of patients with blindness in developing countries  5% of patients with blindness in developed countries  Can be congenital or acquired  Etiology / Risk Factors  Aging most common reason  Diabetes Mellitus  Smoking  Eye trauma  Corticosteroid use  Some psychotropic meds  Age Related Classification  Nuclear cataract  Lens may have yellow appearance  Progresses slowly – may not affect vision until later in the process  Cortical cataract  Vision not affected unless the visual axis or most/all of the cortex is involved  Lens may have a white and milky appearance  Posterior subcapsular cataract  May affect younger patients  May cause glare  May reduce near vision more than distance  Presentation History (Nuclear)  Usually slow and progressive loss of visual acuity  Glare and haloes from lights  Double vision or ghosting  Often asymmetrical  Reduced color intensity  Challenges recognizing faces or small distant objects  Often intact near vision Nuclear Nuclear Nuclear  Uveitis  Uvea consists of the iris, choroid, and ciliary body  Uveitis – inflammation of one or more tissues of the uvea  Iritis is anterior uveitis  Cause may be local or systemic  JRA, sarcoidosis, Pneumocystis carinii, autoimmune  Uveitis – infectious causes  Herpes virus  Keratouveitis can involve the cornea (anterior)  Cytomegalovirus (CMV)  Posterior most often  Usually found in immunocompromised pts (HIV)  Toxoplasmosis  May be reactivation of congenital acquisition  Other causes  Syphillis, TB, cat-scratch, West Nile, Ebola, Zika  Uveitis – inflammatory causes  Spondyloarthritis (SpA)  Ankylosing spondylitis / reactive arthritis (HLA-B27)  20-40% develop anterior uveitis  Typically unilateral  Sarcoidosis  ~20% present with eye sx as initial presentation  Juvenile idiopathic arthritis (JIA)  Usually between ages of 2-8  Usually bilateral with slow onset  Psoriatic arthritis and IBD  Often have a SpA component  Uveitis – usually restricted to the eye  Post-traumatic (including surgery)  Idiopathic  Subconjunctival Hemorrhage  Common in elderly (>80 y/o) with systemic dz  In 5 years Neovascularization Neovascularization Retinal Detachment Retinal Detachment  Nonproliferative Retinopathy (NPDR)  Variable appearance of:  Nerve-fiber layer infarcts (cotton wool spots)  Intraretinal hemorrhages  Hard exudates  Microvascular abnormalities (microaneurysms, occluded vessels, and dilated or tortuous vessels)  Vision loss secondary to macular edema  Categorized into mild, moderate, severe, and very severe Retinal hemorrhage and microaneurysms  Hypertensive retinopathy  Severe forms of HTN create both acute and ongoing target organ damage (including eyes, kidneys, and hypertensive encephalopathy)  Increasing retinal microvascular changes  Mechanisms:  Arterial and arteriolar vasoconstriction as compensation for increased pressure  When BP is too high or sustained, autoregulation fails  Rising pressure damages vascular walls  When vasodilation occurs, can lead to cerebral edema  HTN retinopathy usually associated with diastolic BP of >120mmHg  Expect neuro sx as well  Hypertensive retinopathy  Classifications  Mild – Retinal arteriolar narrowing related to vasospasm, arteriolar wall thickening or opacification, and arteriovenous nicking, referred to as "nipping".  Moderate – Hemorrhages, either flame or dot-shaped, cotton- wool spots, hard exudates, and microaneurysms.  Severe – Some or all of the above, plus optic disc edema. The presence of papilledema mandates rapid lowering of the blood pressure. Copyrights apply  Age-related Macular Degeneration (AMD)  Degenerative dz of central portion of retina (macula)  Loss of central vision  Leading cause of blindness  Affects many ADLs  Classifications:  Dry (atrophic)  Wet (neovascular or exudative)  Pathogenesis unclear Copyrights apply  Dry AMD  Early lesions more common  Findings may include:  Drusen  Localized deposits of extracellular material  Can be hard, soft, or crystalline and calcific  Progression to advanced AMD increases with amount of soft drusen  Geographic atrophy of the retinal pigment epithelium  Thinning and loss of tissue in the macula  Pigment epithelial detachments  Subretinal pigment epithelial clumping  Wet AMD  More common than dry in advanced AMD  Large soft drusen or pigmentary clumping increases risk of Wet AMD  References  American Academy of Ophthalmology - https://www.aao.org/eye-health/diseases/what-are- cataracts  Dynamed - Cataracts in Adults  Robbins and Coltran. Pathologic Basis of Disease. 9th ed. Ch. 29  Up To Date  https://collections.lib.utah.edu/ark:/87278/s68d2ss q  https://www.ncbi.nlm.nih.gov/books/NBK545310/