Age-related macular degeneration

Age-related macular degeneration

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Age-related macular degeneration (AMD) is the leading cause of blindness in elderly patients [1] and is classified as either non-exudative (i.e., dry) or exudative (i.e., wet or neovascular). The clinical manifestations of non-exudative AMD range from incidental findings of drusen to geographic atrophy causing significant vision loss, and approximately 15% of AMD patients ultimately transition to the wet form [2]. This conversion is due to the extension of choroidal vessels into the sub-retinal pigment epithelial (sub-RPE) or sub-retinal space via breaks in Bruch's membrane. AMD has been categorized by The Age-Related Eye Disease Study (AREDS) based on exam findings of hard drusen, soft drusen, RPE abnormalities, atrophy, and choroidal neovascularization [3]; the AREDS categories are as follows:

• Category 1 (No AMD): a few (5-15), small (<63µm) or no drusen without pigment changes.
• Category 2 (Early AMD): Several small drusen, few intermediate-sized (63-124µm) drusen, and/or pigmentary changes in one or both eyes
• Category 3 (Intermediate AMD): Extensive (i.e., 20 soft or 65 hard without any soft) intermediate-sized drusen, one large (>125µm) druse, and/or geographic atrophy not involving the macula in one or both eyes
• Category 4 (Advanced unilateral AMD): Advanced dry form (i.e., macula-involving geographic atrophy) or exudative form with choroidal neovascularization in one eye
• Category 4a: Advanced AMD in one eye with category 1, 2, or 3 AMD in the fellow eye
• Category 4b: Advanced AMD in one eye and decreased visual acuity (<20/32) secondary to AMD in the fellow eye; however, advanced AMD is not present in both eyes

The importance of daily Amsler grid monitoring should be emphasized to maximize the opportunity to detect early development of wet AMD in either eye. The benefit of micronutrients (e.g., AREDS vitamins) in delaying the progression of AMD has been shown in patients with intermediate and advanced unilateral disease [4]. Patients should be informed of the association between smoking and an increased risk of developing AMD [5].