Abstract
Purpose:
To asses macular photoreceptor abnormalities in eyes with fundus albipunctatus associated with RDH5 mutation using adaptive optics scanning laser ophthalmoscopy (AO-SLO).
Methods:
Ten eyes of 5 patients with fundus ablipunctatus associated with RDH5 mutation (4 men and 1 woman from 4 families; mean age, 29.6 y; range, 15-64y) and 11 eyes of 11 volunteers underwent a full ophthalmologic examination, color fundus photography, microperimetry, spectral-domain optical coherence tomography (SD-OCT), and imaging with a prototype AO-SLO system. Cone density and spatial organization of the cone mosaic were assessed using AO-SLO images.
Results:
Four patients from 3 families had the same mutation in RDH5, (c.928delC/ insGAAG). One patient had another mutation in RDH5 (c.718delG), which was the novel mutation of RDH5 gene. AO-SLO revealed the presence of small patchy dark areas representing cone loss in the macula of all eyes with fundus albipunctatus, which was true even in eyes for which SD-OCT did not reveal any visible defects in the photoreceptor layer. AO-SLO and SD-OCT showed microhole-like photoreceptor defect in the fovea in 1 eye. In eyes with fundus albipunctatus, cone density was significantly lower in each area at 0.5 mm and 1.0 mm from the center of the fovea compared to normal eyes (P = 0.014 for both). At 0.5 mm and 1.0 mm from the center of the fovea, a decreased number of cones had 6 neighbors in eyes with fundus albipunctatus (P = 0.022 and 0.002). The ratio of observed mean nearest neighbor distance (NND) for each subject divided by expected NND (computed assuming a perfectly hexagonal lattice of cones with a density equal to that observed for a given subject) was significantly lower for eyes with fundus albipunctatus than for normal eyes at 0.5 mm and 1.0 mm from the center of the fovea (P=0.007 and 0.001). Mean retinal sensitivity was significantly lower in the area with white dots, compared with area without them (11.2 ± 2.6 dB and 13.9 ± 3.1 dB, P<0.001).
Conclusions:
Macular cone density is decreased and the regularity of the macular cone mosaic spatial arrangement is disrupted in eyes with fundus albipunctatus, even when SD-OCT shows normal photoreceptor layer. AO-SLO imaging is a sensitive quantitative tool for detecting photoreceptor abnormalities in eyes with fundus albipunctatus.
Keywords: 550 imaging/image analysis: clinical •
648 photoreceptors •
688 retina