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Mohammad Ali Sadiq, Nithya Rajagopalan, Kathleen Ellen Guinn, Mostafa Saad Hanout, Liz Julieth Zapata, Jose Maya, Salman Sarwar, Diana V Do, Quan Dong Nguyen, Yasir Sepah; Structural characteristics of retinal layers adjacent to Geographic Atrophy. Invest. Ophthalmol. Vis. Sci. 2014;55(13):5889.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate retinal structures adjacent to areas of geographic atrophy (GA) secondary to age related macular degeneration (AMD) as compared to retinal layers of eyes with no known diseases.
Spectralis optical coherence tomography (OCT) scans from 339 patients with non-neovascular AMD managed at a tertiary care eye center acquired over a 5-year period (2008-2013) were reviewed. Eyes with history of neovascular AMD were excluded. All eyes with findings of GA on Spectralis OCT were included. Two scans with no findings suggestive of GA changes on OCT were selected from the areas immediately above and/or below the GA lesion. Spatial changes in retinal layers were calculated along a 5-mm horizontal B-scan using Heyex Explorer v.5.2 in increments of 0.5 mm. Average thickness values of full retinal thickness (FRT), retinal pigment epithelium (RPE), photoreceptor (PR), bipolar cell (BP), and combined ganglion cell/nerve fiber layers (GCL-NFL) were calculated. The distances to the segmented scans from a central horizontal line passing through the fovea were measured. Thickness values were then compared to corresponding values obtained from identical locations in normal eyes of age-matched volunteers. Standard deviations (SD) were calculated with reference to normal.
30 patients (44 eyes) with evidence of GA were included. Mean age was 80 years; 21 (70%) were female. The normal group included 20 volunteers, 16 (70%) of which were female with a mean age of 59. Among the 73 segmentations that were performed on the 44 eyes, only three demonstrated thickness changes greater than two SDs from the normal in at least one layer. Differences among thickness values for all individual retinal layers in the remaining segmentations did not show a change greater than two standard deviations. These results were similar along the central, temporal and nasal aspects of the B-scan passing through the fovea.
Spectral domain OCT can be used to distinguish regions of abnormality in eyes with GA. Descriptive analysis revealed that the thickness of the retinal layers adjacent to areas of GA are not different from those of normal retinae. Management options can be aimed to preserve the adjacent retina as it does not seem to be affected by GA.
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