Ophthalmology · Retinal Disorders
The facts most likely to be tested
Dry (atrophic) AMD is the most common form and is characterized by the accumulation of drusen (yellow subretinal deposits) in the macula.
Wet (neovascular/exudative) AMD is characterized by choroidal neovascularization leading to rapid, severe central vision loss.
Patients with wet AMD typically present with metamorphopsia, which is the distortion of straight lines appearing wavy on an Amsler grid.
The Amsler grid is the primary screening tool used by patients at home to monitor for the progression of macular degeneration.
Smoking is the most significant modifiable risk factor for the development and progression of both dry and wet AMD.
AREDS2 formulation (vitamins C, E, zinc, copper, lutein, and zeaxanthin) is indicated to slow the progression of intermediate dry AMD to advanced disease.
Intravitreal anti-VEGF injections (e.g., ranibizumab, bevacizumab, or aflibercept) are the first-line treatment for wet AMD to inhibit abnormal vessel growth.
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A 78-year-old female presents to the clinic complaining of difficulty reading and recognizing faces over the past three months. She reports that when she looks at her window blinds, the lines appear wavy and distorted. Her medical history is significant for a 40-pack-year smoking history. On physical examination, visual acuity is 20/70 in the right eye and 20/40 in the left eye. Funduscopic examination reveals subretinal fluid and gray-green subretinal discoloration in the macula of the right eye.
What is the most appropriate next step in management for this patient?
Intravitreal anti-VEGF injection
The patient's presentation of metamorphopsia and funduscopic findings of subretinal fluid are classic for wet AMD, which requires urgent treatment with anti-VEGF agents to prevent further vision loss.
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High yield triage
Etiology / Epidemiology
Leading cause of permanent central vision loss in patients >50. Smoking is the most significant modifiable risk factor.
Clinical Manifestations
Painless, bilateral central vision loss. Metamorphopsia (wavy lines) on Amsler grid testing.
Diagnosis
Optical Coherence Tomography (OCT) is the gold standard. Look for drusen in dry or subretinal fluid in wet.
Treatment
Dry: AREDS2 vitamins. Wet: Intravitreal anti-VEGF injections (e.g., ranibizumab).
Prognosis
Wet AMD causes rapid, severe vision loss. 90% of blindness is attributed to the neovascular (wet) form.
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Epidemiology & Etiology
AMD is the primary cause of irreversible central vision loss in the elderly. Major non-modifiable risk factors include advanced age and Caucasian race. Smoking significantly increases the risk of progression to advanced disease.
Pertinent Anatomy
The macula is the central portion of the retina responsible for high-acuity, color vision. The fovea, located at the center of the macula, contains the highest density of photoreceptors.
Pathophysiology
Dry (atrophic) AMD involves the accumulation of drusen—yellow subretinal deposits of extracellular debris. Wet (neovascular) AMD occurs when abnormal choroidal neovascularization breaks through Bruch's membrane. This leads to fluid leakage, hemorrhage, and subsequent fibrotic scarring of the macula.
Clinical Manifestations
Patients present with progressive, painless central vision loss and metamorphopsia. The Amsler grid test is used to detect distortion of straight lines. Sudden, rapid vision loss suggests progression to the wet (neovascular) form, which is a clinical emergency.
Diagnosis
Optical Coherence Tomography (OCT) is the gold standard for diagnosis and monitoring. Fluorescein angiography may be used to identify active neovascularization. Clinical exam reveals drusen (dry) or subretinal fluid/hemorrhage (wet).
Treatment
Dry AMD management focuses on AREDS2 formulation (vitamins C, E, zinc, copper, lutein, zeaxanthin) to slow progression. Wet AMD requires Intravitreal anti-VEGF injections (e.g., ranibizumab, aflibercept, or bevacizumab). Avoid systemic VEGF inhibitors in patients with recent stroke or myocardial infarction.
Prognosis
Wet AMD is responsible for the majority of severe vision loss. Patients require frequent monitoring with Amsler grids at home to detect acute changes. Laser photocoagulation is rarely used now due to the success of anti-VEGF therapy.
Differential Diagnosis
Diabetic Retinopathy: presence of microaneurysms and cotton-wool spots
Retinal Detachment: sudden onset of 'curtain coming down' and flashes/floaters
Central Retinal Artery Occlusion: sudden, painless, unilateral monocular blindness with 'cherry-red spot'
Glaucoma: peripheral vision loss progressing to central, usually with elevated intraocular pressure
Cataracts: gradual, painless blurring of vision with glare and halos