No abstract

Purpose-Geographic atrophy (GA) may cause significant compromise of visual function, even when there still is good visual acuity (VA), because of parafoveal scotomas and foveal function abnormalities antedating visible atrophy. This study evaluates the visual function abnormalities at baseline and the 2-year worsening of VA and reading rate for eyes with GA compared with a group of eyes with drusen only.Methods-Seventy-four eyes with GA and VA greater than or equal to 20/50 from a prospective natural history study of GA were included, as were 13 eyes with only drusen. Baseline visual function testing and 2-year VA and maximum reading rate are reported.Results-The worsening of VA in decreased luminance and foveal dark-adapted sensitivity showed severe abnormalities for the GA group. Contrast sensitivity was significantly reduced for the eyes with GA. Half the eyes with GA, but none of the drusen eyes, had maximum reading rates below 100 words per minute. A scanning laser ophthalmoscope (SLO) measure of the scotoma near fixation combined with a measure of residual foveal function accounted for 54% of the variability in maximum reading rate in the eyes with GA.Of 40 eyes with GA observed for 2 years, half lost greater than or equal to 3 lines of VA and one quarter lost greater than or equal to 6 lines. The nine eyes with drusen with follow-up had no significant change in VA. Low foveal dark-adapted sensitivity, SLO measures of the scotoma within 1° of fixation, and low maximum reading rate were statistically significant risk factors for doubling of the visual angle. Significant reduction in maximum reading rates at 2 years was present for the eyes with GA.Conclusions-The eyes with GA with good VA have profound decreases in visual function, particularly in dim lighting and in reading. Half the eyes with GA had doubling in visual angle at 2 years after the baseline examination, whereas the drusen eyes remained essentially unchanged. Impaired visual function at baseline was predictive of an adverse outcome for the eyes with GA.Address correspondence to Janet S. Sunness, MD, 550 N. Broadway, 6th Floor, Baltimore, MD 21205. The baseline visual function abnormalities were presented at the 1995 meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida. The natural history aspect of this article is being submitted as an abstract for presentation at the 1997 American Academy of Ophthalmology Meeting, San Francisco, California.The authors have no proprietary interest in the development or marketing of instruments used in this study or in competing instruments. NIH Public Access Author ManuscriptOphthalmology. Author manuscript; available in PMC 2009 August 23. Published in final edited form as:Ophthalmology. 1997 October ; 104(10): 1677-1691. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptGeographic atrophy (GA) of the retinal pigment epithelium (RPE) is a form of advanced agerelated macular degeneration (AMD) that can cause central visual loss. It differs...

Purpose-To report the enlargement rate of geographic atrophy (GA) over time, its relationship to size of atrophy at baseline and to prior enlargement rate, and the implications for designing future treatment trials for GA.Design-Prospective natural history study of GA resulting from age-related macular degeneration.Participants-Two hundred twelve eyes of 131 patients were included in the analysis.Methods-Annual follow-up included stereo color fundus photographs. The areas of GA were identified and measured, and the rate of enlargement of the atrophy was assessed. Sample sizes for clinical trials using systemic treatment and uniocular treatment were determined. Main Outcome Measure-Rate of enlargement of the atrophy.Results-The median overall enlargement rate was 2.1 mm 2 /year (mean, 2.6 mm 2 /year). Eyes with larger areas of atrophy at baseline tended to have larger enlargement rates, but knowledge of prior rates of enlargement was the most significant factor in predicting subsequent enlargement rates. There was high concordance between the enlargement rates in the 2 eyes of patients with bilateral GA (correlation coefficient, 0.76). To detect a 25% reduction in enlargement rate for a systemic treatment (α, 0.05; power, 0.80; losses to follow-up, 15%), 153 patients each in a control and treatment group would be required for a trial with a 2-year follow-up period for each patient. For a uniocular treatment, 38 patients with bilateral GA would be required, with the untreated eye serving as a control for the treated eye. Because GA is a degenerative rather than a neovascular disorder, the possible methods for treatment of this disorder are likely to be different than those for choroidal neovascularization (CNV). To date, there is no definite treatment for GA. Limited information on GA from the Age-Related Eye Disease Study has been published. 12 The findings presented did not attain statistical significance, and there were some contradictory findings, perhaps because of the small numbers. To design future studies of potential therapies for GA, it is important to know the natural history of GA. Conclusions-TreatmentThis article reports our long-term prospective findings of the enlargement of the area of atrophy in GA. We also explore issues important for the design of future treatment trials, including sample size calculations and appropriate eligibility criteria for baseline GA area. Patients and Methods Patients and Annual ExaminationsPatients with GA associated with AMD were enrolled in our National Institutes of Healthfunded prospective natural history study, which ran from 1992 through 2000. Patients were evaluated annually. Eligibility criteria included having an area of GA of at least 500 µm in diameter in the absence of CNV (assessed clinically and by fluorescein angiography) in one or both eyes. At each examination, a battery of visual function tests also was performed, as described previously. 13 Thirty-degree and, when possible, 60° color fundus photographs were obtained at each examination. Fluo...

There is a preference for fixation with the scotoma to the right in eyes with GA. Patients with Stargardt disease use different strategies for fixation, perhaps due to subclinical pathology adjacent to the atrophic regions. The size of the atrophic area in GA plays the predominant role in reading rate for eyes that have already lost foveal vision.