Age-related macular degeneration (AMD) is a degenerative disease of the retina and represents the most common cause of blindness in individuals > 65 years in developed countries. It is classified into two major forms: dry AMD and wet AMD. Dry AMD is caused by deposition of various metabolites under the retinal pigment epithelium (drusen) and usually develops over decades, while wet AMD is caused by neovascularizations growing into the subretinal space and manifests within weeks to months or even acutely. Both forms ultimately cause impaired central vision and can, in rare cases, lead to complete blindness. Patient history and clinical tools such as the Amsler grid can provide clues regarding visual impairment. Fundoscopy is needed to identify specific pathological changes. Fluorescein angiography may be used to confirm the diagnosis of wet AMD. Treatment focuses on slowing vision loss and/or improving vision.
AMD is the leading cause of blindness in individuals > 65 years in developed countries.
Epidemiological data refers to the US, unless otherwise specified.
Dry AMD (∼ 90%)
- Also referred to as nonexudative AMD or atrophic AMD
- Deposition of yellow-whitish material consisting of lipids, vitronectin, and other proteins (drusen) in the retinal pigment epithelium and between it and Bruch membrane → slow progressive atrophy of the local retinal pigment epithelium (centrally or pericentrally)
- Wet AMD (∼ 10%)
Painless central or pericentral visual impairment → reduced visual acuity, difficulty adapting to changes in lighting
- Dry AMD: slow progressive visual impairment (usually over decades) and unilateral or bilateral onset
- Wet AMD: acute or insidious onset (over weeks to months) and usually manifests in one eye first
- Metamorphopsia; : type of visual distortion in which straight lines appear wavy, which can be tested for using an Amsler grid
- Scotoma (blind spot)
Both, wet and dry AMD
- Amsler grid: detection of metamorphopsias and scotomas
If wet AMD is suspected
- Fluorescence angiography
- Color fundus photography: enables evaluation of disease progression and interpretation of fluorescein angiography
Optical coherence tomography (OCT)
- Detection of intraretinal or subretinal fluid retention
- Helps confirm diagnosis of wet AMD and to monitor progress under treatment
|Differential diagnosis of vision loss|
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The differential diagnoses listed here are not exhaustive.
No causal treatment is available.
- Supportive treatment
Treatment of wet AMD
- First-line: injection of VEGF inhibitors (ranibizumab, bevacizumab, pegaptanib) into the vitreous body
- Second-line: when VEGF is contraindicated
- Chronic progressive course for both types
- Prognosis for dry AMD is significantly better than for wet AMD
- Complete loss of central vision is possible but rare