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N.P. Blair, M. Shahidi, A. Shakoor, R. Zelkha; Thickness of Retinal Layers in Age–Related Macular Degeneration with Geographic Atrophy of the Retinal Pigment Epithelium . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5675.
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© ARVO (1962-2015); The Authors (2016-present)
To test the hypothesis that the outer retinal layers are selectively thinned in areas with geographic atrophy (GA) of the retinal pigment epithelium in age–related macular degeneration (AMD).
Optical coherence tomography (OCT) was performed using a commercially available Stratus OCT instrument on 10 eyes of 10 normal subjects and 8 eyes of 8 patients with GA caused by AMD. A dedicated software algorithm was used to measure the inner retinal thickness (IRT), outer retinal thickness (ORT) and total retinal thickness (TRT) along the horizontal OCT scans. The algorithm found the transition between the bright and dark bands on the OCT images near the outer plexiform layer as the interface between the inner and outer retinal layers. Each scan was divided into 5 equal segments along its length, and each area was graded for the presence or absence of GA on fluorescein angiography and color fundus photography. The thicknesses of the retinal layers were normalized by dividing the measurements by the mean normal values at the same locations.
In the AMD patients, the average normalized IRT, ORT and TRT were 1.01 ± 0.26, 0.95 ± 0.12, and 0.94 ± 0.14 and 0.91 ± 0.12, 1.10 ± 0.15 and 0.96 ± 0.09 in the areas with and without GA, respectively, and 1.02 ± 0.11, 1.05 ± 0.11 and 1.02 ± 0.09 in the normal subjects. The average normalized ORT, but not IRT or TRT, was less in the areas with GA as compared to areas without atrophy in the patients with AMD (P = 0.05). The average normalized ORT was less in areas with GA than in areas of normal subjects (P = 0.035).
The outer retinal layers were selectively thinned in areas with GA associated with AMD.
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