What physical exam findings are consistent with Age-related Macular Degeneration (AMD)?

Physical Exam Findings Consistent with Age-Related Macular Degeneration

The most important physical exam findings consistent with age-related macular degeneration (AMD) include drusen, retinal pigment epithelial changes, geographic atrophy, and evidence of choroidal neovascularization such as intra- or subretinal hemorrhage, lipid, and fluid. 1

Early and Intermediate AMD Findings

Drusen

• Small drusen (<63 μm in diameter)
• Intermediate drusen (≥63 μm and ≤125 μm)
• Large drusen (>125 μm)
• Soft drusen (characterized by ill-defined edges) 1
• Confluent drusen (multiple drusen that merge together) 1

Retinal Pigment Epithelium (RPE) Changes

• Hypopigmented areas (RPE atrophy)
• Hyperpigmented areas (RPE clumping)
• Retinal pigment epithelial abnormalities surrounding drusen 1

Advanced AMD Findings

Geographic Atrophy (Dry AMD)

• Well-demarcated zones of RPE atrophy
• Sometimes choriocapillaris atrophy
• Drusen usually present surrounding these zones
• Surrounding pigment clumping may be visible 1
• Visible choroidal vessels in areas of atrophy

Neovascular AMD (Wet AMD)

• Intraretinal hemorrhage
• Subretinal hemorrhage
• Lipid exudates
• Intraretinal fluid
• Subretinal fluid
• Retinal pigment epithelial detachments 1
• Disciform scar (late finding) - subretinal fibrovascular tissue that becomes more fibrous over time 1

Clinical Examination Techniques

1. Dilated Fundus Examination

   • Essential for visualizing drusen, pigmentary changes, and signs of advanced AMD
   • Special lens that focuses light of the slit lamp through the pupil is required 2

2. Amsler Grid Testing

   • Helps detect metamorphopsia (distortion of vision)
   • Patient views a central spot and evaluates for any changes in the grid pattern 1

3. Optical Coherence Tomography (OCT)

   • Provides high-resolution, cross-sectional images of retinal structure
   • Can detect fluid, pigment epithelial detachments, and geographic atrophy 3

4. Fluorescein Angiography

   • Helps classify choroidal neovascularization (classic vs. occult)
   • Classic CNV appears as bright, well-demarcated hyperfluorescence in early phases
   • Occult CNV shows fibrovascular RPE detachment and/or late leakage 1

Clinical Pearls and Pitfalls

• AMD is usually asymptomatic in early stages, making fundus examination crucial for early detection 1
• The presence of intermediate or large drusen significantly increases the risk of progression to advanced AMD 1
• Bilateral soft drusen, large drusen, and confluent drusen are particularly concerning for progression 1
• Geographic atrophy is considered an advanced form of AMD only when the center of the fovea is involved 1
• Early detection is critical as anti-VEGF treatment for neovascular AMD is most effective when initiated promptly 1
• Cigarette smoking is a major modifiable risk factor for AMD progression 1
• AMD prevalence increases significantly with age, from 0.3% in white females aged 60-64 to 16.4% in those 80 and older 1

By systematically examining for these findings, clinicians can accurately diagnose AMD, determine its stage, and implement appropriate management strategies to preserve vision and quality of life.