Extramacular Drusen and AMD Progression
By Jean Shaw
Selected by Andrew P. Schachat, MD
Journal Highlights
Ophthalmology Retina, February 2023
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Domalpally et al. set out to assess the prevalence of extramacular drusen and their role in the progression of age-related macular degeneration (AMD). They found that extramacular drusen are commonly observed in eyes with AMD and are more frequent with an increased drusen load within the macula. However, in eyes with intermediate AMD, extramacular drusen do not confer any additional risk of progression to late AMD.
For this retrospective analysis of data from the Age-Related Eye Disease Study 2 (AREDS2), the researchers evaluated 4,168 eyes of 2,998 participants. All had intermediate AMD in one or both eyes. The presence of drusen outside the macular grid was documented at all study visits via three-field 30-degree color photographs. The characteristics of the extramacular drusen were then compared with those of drusen within the macula. The main outcome measure was the rate of progression to late AMD (both geographic atrophy and neovascular AMD).
All told, extramacular drusen were observed in 3,634 eyes (87%). There was no difference in participant age, sex, smoking status, diabetes, hypertension, angina, statin use, and AREDS2 randomization arm between those with and without extramacular drusen (all p > .05), and the mean VA was similar at 79.5 and 78.4 letters, respectively. With regard to drusen area (DA), as based on drusen circles, this was small (<.5 mm2) in 50.3% of affected eyes and ≥1 DA in only 14.5% of affected eyes. Pigment changes were observed in only 3.6% of eyes in the extramacular region.
During five years of follow-up, progression to late AMD was observed in 1,259 eyes (35.8%) with and in 178 eyes (33.3%) without extramacular drusen. Progression to GA, central GA, and neovascular AMD in eyes with and without extramacular drusen was 19.4% versus 17%, 9.7% versus 8.2%, and 19.1% versus 19.9%, respectively.
In their discussion, the authors noted that, in eyes with intermediate AMD, extramacular drusen “are not an independent risk factor in and do not provide added risk to previously identified risk factors for progression to late AMD. The role of drusen in the midperiphery and peripheral retina remains to be studied.”
The original article can be found here.