Abstract
Abstract: :
Purpose: To study the acquisition of a new preferred retinal locus for fixation (PRL) in eyes with GA from AMD followed from baseline, when acuity was 20/50 or better, to when visual acuity fell to 20/200 or worse. Methods: Patients enrolled in the prospective natural history study of GA underwent annual best–corrected visual acuity, scanning laser ophthalmoscope (SLO) analysis of scotomas and fixation, and measurement of atrophy from fundus photographs. Results: Of the patients who had follow–up and did not lose vision from subsequent CNV, there were 64 patients with GA and visual acuity of >=20/50 in one eye (51 patients) or both eyes (13 patients) at baseline, for a total of 77 eyes studied with good baseline acuity. By the end of follow–up, (median 4.6 years, range 1 to 7.1 years overall), 17 eyes retained VA >=20/50 (median f/u 3.7 y), 42 eyes had acuities between 20/50 and 20/200 (median f/u 4.6 y), and 18 eyes had acuities of 20/200 or worse (median f/u 5.3 y). Of the 18 eyes with acuities of 20/200 or worse by the end of the follow–up period, 4 had not developed a PRL, 4 still fixated in a spared region within the atrophy, 3 fixated below the scotoma in visual field space, 2 fixated above, 3 fixated to the left, and 2 fixated to the right of the scotoma. Seven eyes had less than one year f/u after VA had fallen into this level, while 12 eyes had f/u between 1 and 4 years, median 2.5 years, after VA had fallen. Four of the eyes changed the pattern of fixation, from the site at the time when the vision first fell to this level, to the end of f/u. Conclusions: Studying the prospective acquisition of an eccentric PRL when visual acuity falls can help to understand the processes involved in establishing a PRL.
Keywords: age–related macular degeneration • low vision • clinical (human) or epidemiologic studies: natural history