Purpose:
To assess the nature and extent of macular drusen regression over a two-year period in patients with intermediate age-related macular degeneration (AMD), and to evaluate associated changes in fundus autofluorescence (FAF).
Methods:
Sixty patients, aged 50 years and older, were enrolled in the National Eye Institute clinical site for the Age-Related Eye Disease Study 2 (AREDS2). At baseline, they had either large drusen (≥125 µm) in both eyes, or large drusen in one eye and advanced AMD in the fellow eye. They were prospectively imaged with color and monochromatic fundus photography and with modified fundus camera-based (mFC) FAF imaging at baseline and at two years. The mFC was equipped with a black and white digital sensor, and used a 580nm excitation filter with a 700nm band pass emission filter. One eye of each patient with intermediate AMD and large drusen at baseline was admitted for study. Eyes that progressed to neovascular AMD by two years were excluded from analysis (n = 2). Comparative analyses of overlays of fundus photographs taken at baseline and year two were used to identify and delineate areas of drusen regression greater than or equal to circle C1 (125 µm diameter) on the AREDS maculopathy grading protocol. Changes in FAF patterns within regions of drusen regression were analyzed.
Results:
Of 58 eyes with intermediate AMD at baseline and two years, 28 (48%) eyes demonstrated one or more areas of drusen regression in the macula exceeding circle C1 in size. At baseline, the majority of these delineated areas were associated with abnormal patterns of FAF, consisting of areas of both increased and decreased FAF. At two years, these patterns of abnormal FAF were noted to undergo significant change, generally corresponding to expansions in the overall areas of decreased FAF. However, none of the areas of drusen regression were found to be associated with the emergence of frank geographic atrophy.
Conclusions:
Drusen regression is a frequent finding in eyes with intermediate AMD that are at risk for progression. While drusen regression was not associated with overt atrophy on clinical examination or fundus photography, affected areas demonstrated alterations in the patterns of FAF. These associated changes in FAF suggest that drusen regression may be accompanied by structural and compositional changes in the aging retinal pigment epithelium that may constitute part of AMD pathogenesis.
Clinical Trial:
http://www.clinicaltrials.gov NCT00345176
Keywords: age-related macular degeneration • imaging/image analysis: clinical • retinal pigment epithelium