• FAF Imaging and Progression of Geographic Atrophy in AMD

    By Jean Shaw
    Selected By: Andrew P. Schachat, MD

    Journal Highlights

    Ophthalmology Retina, September 2019

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    Holmen et al. used fundus autoflu­orescence (FAF) imaging to evaluate the sequence of progression leading to geographic atrophy (GA) in patients with age-related macular degeneration (AMD). They found that GA can evolve from a variety of changes as seen on FAF. Moreover, they noted that, in most eyes, predominant hypoautofluores­cence appears to be the final step before GA is visible.

    This study was a post hoc analysis of images from the Age-Related Eye Disease Study 2 (AREDS2), which evaluated the impact of nutritional supplements on AMD progression. The researchers included 120 eyes (109 participants) with at least two years of FAF images. The first visit at which GA was identified on FAF was considered the incident visit. Images from incident visits were stacked and aligned over previous annual FAF images from the same eye, allowing for pixel-to-pixel correlation between images of se­quential visits. Images were graded subjectively and independently by two certified graders at the University of Wisconsin Reading Center.

    All precursor images were classified as either 1) minimal change autofluo­rescence, 2) predominant hypoautoflu­orescence (decreased autofluorescence), 3) predominant hyperautofluorescence (increased autofluorescence), or 4) mixed autofluorescence. Main outcome measures were GA area and rate of enlargement.

    At 1.0 mm2, the mean area of inci­dent visit GA on FAF was significantly smaller than the mean area of inci­dent GA and baseline GA previously described in clinical trials. The mean enlargement rate of incident GA was 0.97 mm2 per year. Although precursor lesion classification was not associated with the area of incident GA, it was associated with enlargement rate, and minimal-change autofluorescence le­sions were linked to faster enlargement rates.

    Among all types of precursor lesions, predominant hypoautofluorescence lesions were the most common: Three years before GA developed, they ac­counted for 42% of precursor lesions; this percentage grew to 81% one year before GA developed.

    The original article can be found here.