Age-Related Macular Degeneration (AMD) Lecture Flashcards

This set covers anatomy, pathophysiology, classification, symptoms, and management of Age-Related Macular Degeneration based on lecture materials.

Age-Related Macular Degeneration (AMD)

A degeneration affecting the macula characterized by drusen and retinal pigment epithelium (RPE) changes, and sometimes choroidal neovascularisation (CNV).

Retinal Pigment Epithelium (RPE)

A monolayer rich in pigment particles like melanin that supports photoreceptors and maintains the visual process; its phagocytic ability declines with age.

Choriocapillaris

The capillary layer of the choroid that supplies oxygen and nutrients to the outer retina, including the photoreceptors and RPE.

AMD Global Prevalence

$8.7\%$ of the worldwide population, making it the leading cause of blindness and visual impairment in older populations.

AMD Risk Factors (Non-Modifiable)

Increasing age ($3 \times$ risk in patients $> 75$ vs $65-74$ years), genetics ($34$ different loci identified), and race (higher in Caucasians).

AMD Risk Factors (Modifiable)

Smoking (strongest modifiable factor, doubles risk), hypertension, cardiovascular disease, BMI of $\ge 30\,kg/m^2$, and diet low in omega-3/antioxidants.

Drusen

Yellowish deposits of harmful proteins and fats between the RPE and Bruch’s membrane caused by RPE stress and waste removal failure.

"Hard" Drusen

Small, round, discrete, yellow-white spots located on top of Bruch's membrane.

"Soft" Drusen

Larger, pale-yellow deposits with indistinct margins located nearer to the RPE; associated with ischemia and choroidal neovascularisation.

Metamorphopsia

A symptom of AMD where vision is distorted, causing straight lines to appear wavy.

Micropsia and Macropsia

Visual disturbances where objects appear smaller (micropsia) or larger (macropsia) than their normal size.

Non-exudative (Dry) AMD

The most common form ($90\%$ of cases) characterized by drusen, focal RPE changes, and areas of chorioretinal atrophy.

Exudative (Wet) AMD

Form associated with more rapid progression to sight loss, defined by the presence of macular neovascularization and leakage from abnormal blood vessels.

Early AMD (Beckman Classification)

Medium drusen $> 63\,\mu m$ and $\le 125\,\mu m$ with no AMD pigmentary abnormalities.

Intermediate AMD (Beckman Classification)

Large drusen $> 125\,\mu m$ and/or any AMD pigmentary abnormalities.

Late AMD (Beckman Classification)

The stage of disease involving Neovascular AMD and/or Geographic Atrophy (GA).

Geographic Atrophy (GA)

A chronic progressive degeneration of the macula in late-stage AMD manifesting as loss of photoreceptors and RPE visible on Optical Coherence Tomography (OCT).

AREDS/AREDS 2 Study Finding

Vitamin and zinc supplementation reduced the risk of progression to advanced AMD by $25\%$ and moderate vision loss by $19\%$ at $5$ years.

Amsler Grid

A home monitoring tool used by patients to detect visual distortions or central scotomas for prompt evaluation.

Choroidal Neovascularization (CNV)

Growth of new, leaky blood vessels from the choriocapillaris that can lead to subretinal hemorrhage, fluid, and disciform scars.

Anti-VEGF Therapy

Intravitreal injections (e.g., Avastin/bevacizumab) that block vascular endothelial growth factor to slow blood vessel growth and vision loss.

Polypoidal Choroidal Vasculopathy (PCV)

A subtype of neovascular AMD (nAMD) contributing to $50\%$ of nAMD cases in Asia.

Laser Photocoagulation

A treatment using a focused beam of light to shrink abnormal blood vessels in those with CNV to reduce severe vision loss risk.

Wet AMD Referral Guidelines

Urgent referral to the SOC (Specialist Outpatient Clinic) within $1\text{ week}$ for choroidal neovascular membranes or RPE fibrovascular lesions.