Long-term follow-up of fixation patterns in eyes with central scotomas from geographic atrophy that is associated with age-related macular degeneration

Abstract

Purpose: To study whether fixation patterns changed over time in patients with central scotomas from geographic atrophy from age-related macular degeneration.

Design: Prospective cohort study.

Methods: setting: Institutional. patient or study population: Prospective natural history study of geographic atrophy included 34 eyes of 25 patients with baseline acuity between 20/80 and 20/200 and with subsequent follow-up. observation procedures: Baseline and annual follow-up visits included best-corrected visual acuity, scanning laser ophthalmoscope macular perimetry, reading rate, and clinical evaluation. main outcome measures: Location of eccentric preferred retinal locus for fixation (PRL).

Results: At baseline, 77% of study eyes had a PRL. At the final visit (median follow-up, 5.3 years), 91% of study eyes had a PRL, with 81% of the eyes retaining the baseline PRL location. Fixation with the scotoma to the right and fixation with the scotoma superior were the first and second most common fixation patterns, respectively. Reading rates of <50 words/min were present in 54% of eyes. Eyes fixating with the scotoma to the left tended to have lower reading rates than eyes fixating with right or superior patterns.

Conclusion: Fixation with right pattern remained the most common fixation pattern, both in patients with a PRL at baseline and in patients who had a PRL during follow-up. Eyes with a PRL at baseline generally retained this pattern. The reading rate data suggest an advantage of fixation with right or superior pattern, rather than left. Reading rate declined further during follow-up in most patients.

Figure 1

Progression of geographic atrophy (GA) with a stable fixation pattern. (Left) At baseline, fixation (x) was placed with the atrophy and its corresponding scotoma to the right (circled white areas; there is a nonfoveal spared region within the larger area of GA, which is not used for fixation). At this time, visual acuity was 20/112, and the total area of GA was 3.3 Macular Photocoagulation Study (MPS) disc areas. (Right) Five years later, the GA has enlarged significantly, now measuring 10.3 MPS disc areas. Fixation remains positioned with the atrophy and its corresponding scotoma to the right. At this time, visual acuity was 20/235.

Figure 2

Progression of geographic atrophy (GA) with the adoption of an eccentric preferred retinal locus (PRL). (Left) At baseline, fixation (x) was placed centrally, with surrounding c-shaped geographic atrophy (circled white area). At this time, visual acuity was 20/118, and the total area of GA was 1.2 Macular Photocoagulation Study (MPS) disc areas. (Right) One year later, the GA has enlarged to 2.4 MPS disc areas and involves the central area. Fixation is now maintained superior to the atrophy on the retina, which corresponds to fixation with the scotoma above fixation in visual field space. Visual acuity is now 20/214.

Figure 3

Reading rate as a function of area of atrophy, coded for fixation pattern. Reading rate in words/min (wpm) as a function of the area of the atrophy Macular Photocoagulation Study (MPS) disc areas. The symbols for each eye are coded for the fixation pattern that was present, as noted in the figure. Central = Fixation appears to be at (or near) the foveal center, generally surrounded by multifocal geographic atrophy; I = fixation with the scotoma below (inferior to) fixation in visual field space; L = fixation with the scotoma to the left of fixation; No fix = no fixation site was demonstrated; R = fixation with the scotoma to the right of fixation; S = fixation with the scotoma above (superior to) fixation in visual field space; Sp = fixation is in a spared region within the atrophy.