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Amir H Hariri, Tudor Tepelus, Handan Akil, Muneeswar gupta Nittala, Srinivas R Sadda; Retinal sensitivity at the junctional zone of eyes with atrophic age related macular degeneration.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):46.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the mesopic retinal sensitivity at the junctional zone and uninvolved regions of eyes with geographic atrophy (GA) due to age related macular degeneration (AMD).
Patients with dry AMD were evaluated by microperimetry (Nidek MP-3) and spectral-domain optical coherence tomography (SD-OCT; Cirrus OCT; 512x128 cube) in an IRB-approved study. The mesopic microperimetry test protocol (4:2 threshold) was customized for each eye to include multiple points at varying distances from the edge of the GA lesion. The atrophic lesion was segmented semi-automatically on en face OCT images using the Cirrus Advanced RPE Analysis Tool. The graded en face OCT images were registered to color fundus images with the microperimetric sensitivity values. The junctional zone/region was defined as a ring, 500 microns in width, surrounding the region of GA (Fig 1). This region was further subdivided into “sub-zones”: Zone 1 at the precise border of atrophy; Zone 2 as the center of this junctional region; Zone 3 at the border between the junctional zone and adjacent “normal” retina. An additional Zone 4, was defined as “normal” retina, well-beyond the junctional region (Fig 2).The mean sensitivities of all stimuli within each of these zones (across the entire cohort) were compared, and also compared against the mean sensitivities from eyes with mild or intermediate AMD and no GA.
Seventy-one eyes from 44 patients were included in this study, of which 36 eyes had GA and 35 eyes had mild or intermediate AMD. The mean MP-3 retinal sensitivity of the retina in the various subzones was: Zone 1 = 13.7 ± 4.7, Zone 2 = 20.3 ± 3.9, Zone 3 = 20.9 ± 3.9, and Zone 4= 21.1 ± 4.1 (all in dB). Zone 1 (atrophic margin) sensitivity was significantly lower than all other zones (p <0.001 for all comparisons), but there were no differences between the other zones. The mean sensitivity of the macula in eyes with mild or intermediate AMD was 24.8 ± 2.4 dB, which was significantly higher than the mean sensitivity of the normal-appearing retina (Zone 4) in eyes with GA (p <0.001).
Mesopic retinal sensitivity appears to drop precipitously at the margins of GA. The retinal sensitivity in the bulk of junctional zone is similar to apparently uninvolved distant regions. Of note, the sensitivity in these “normal” regions of eyes with GA is significantly lower than in eyes with less advanced AMD.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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