Changes in Retinal Sensitivity in the Natural History of Geographic Atrophy as Measured Using the Nidek MP-1 Microperimeter

摘要

Purpose: : To describe changes in retinal sensitivity as measured by the MP-1 device during the natural history of geographic atrophy (GA) progression. Methods: : Microperimetric assessments were performed every 6 months in 10 patients with bilateral GA (20 eyes) over 24 months. Nine patients were able to perform the test successfully in both eyes, and results from these 18 eyes were analyzed. A 10?o visual field centered on the anatomic fovea was tested with circular test grid of 68 evenly-spaced stimulation points using a Goldmann III stimulus and a 4-2 staircase strategy. Changes in the following parameters over the study period were assessed: number of scotomatous (non-responding) points, mean retinal sensitivity (dB) of responding points in both peri-lesional and extra-lesional areas and quality of fixation. A mixed model was used to analyze the change in these parameters over time. Results: : Statistically significant changes in retinal sensitivity were detected over the 2-year period of GA progression. The mean number of scotomatous points increased by 4.3 points per year (p=0.0004). Mean retinal sensitivity of all points, all responding points and perilesional points, all decreased significantly (p0.0001). Mean sensitivity of responding points decreased at a rate of 1.1 dB/year. The quality of fixation within the 2?o and 4?o circle also declined significantly over time (p0.002). The rate of increase of scotomatous points was also correlated with the rate of increase of GA area as measured from fundus autofluorescence images (p=0.01). Conclusions: : The natural history of GA progression over time is evident in progressive changes in retinal sensitivity as measured by microperimetry. Microperimetry may be a useful adjunctive assessment modality in following visual function of patients with GA and may contribute outcome measures for interventional studies. Clinical Trial: : www.clinicaltrials.gov NCT00306488.