Change in Cone Structure Over 24 Months in USH2A-Related Retinal Degeneration

Duncan, Jacque L.; Liang, Wendi; Maguire, Maureen G.; Porco, Travis C.; Wong, Jessica J.; Audo, Isabelle; Cava, Jenna; Grieve, Kate; Kalitzeos, Angelos; Kreis, Joseph; Michaelides, Michel; Norberg, Nathaniel; Pâques, Michel; Carroll, Joseph

doi:10.1016/j.ajo.2023.03.006

Cited by 8 publications

(9 citation statements)

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“…Assuming hexagonal cone packing and varying degrees of degeneration of the L/M-cone submosaic, we estimated the overall S-cone percentage and S-cone increase (relative to normal S-cone counts) in ESCS at each eccentricity based on a normal database and previously reported methods. 6 , 8 , 36 , 41 In the normal eye, S-cones make up 5% to 7% of the cone mosaic at the non-foveal eccentricities studied here. 6 By contrast, if no degeneration of the L/M-cone mosaic is assumed in ESCS retinas, we estimate that S-cones constitute 22% of the cone mosaic at 2°; by 7° eccentricity, this number rises to 68% of the receptor array ( Fig.…”

Section: Discussionmentioning

confidence: 66%

“… ( A ) Cone spacing as a function of retinal eccentricity. Normal data 36 , 41 are plotted with black circles on a common eccentricity axis. ( B ) Cone spacing Z -score as a function of retinal eccentricity.…”

Section: Resultsmentioning

confidence: 99%

“…The Z -scores are computed considering retinal locations at four major meridians. 41 The horizontal zero line shows a Z -score of 0, and the gray lines show ±1.96 SD from the mean (95% confidence interval). Cone spacing Z -scores outside of the y -axis range (all of which came from subject 10055) are not shown in the plot.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 4 A shows the cone spacing as a function of eccentricity for 40 normal eyes 41 and the seven ESCS eyes. In normal subjects, cone spacing increases with eccentricity, as cone density declines.…”

Section: Resultsmentioning

confidence: 99%

“… 40 The Z -score value of the cone spacing of each ROI was reported as standard deviations from a normal database at the measured eccentricity. 41 …”

Section: Methodsmentioning

confidence: 99%

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Enhanced S-Cone Syndrome: Elevated Cone Counts Confer Supernormal Visual Acuity in the S-Cone Pathway

Wang

Wong

Duncan

et al. 2023

Invest. Ophthalmol. Vis. Sci.

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Purpose To measure photoreceptor packing density and S-cone spatial resolution as a function of retinal eccentricity in patients with enhanced S-cone syndrome (ESCS) and to discuss the possible mechanisms supporting their supernormal S-cone acuity. Methods We used an adaptive optics scanning laser ophthalmoscope (AOSLO) to characterize photoreceptor packing. A custom non-AO display channel was used to measure L/M- and S-cone–mediated visual acuity during AOSLO imaging. Acuity measurements were obtained using a four-alternative, forced-choice, tumbling E paradigm along the temporal meridian between the fovea and 4° eccentricity in five of six patients and in seven control subjects. L/M acuity was tested by presenting long-pass–filtered optotypes on a black background, excluding wavelengths to which S-cones are sensitive. S-cone isolation was achieved using a two-color, blue-on-yellow chromatic adaptation method that was validated on three control subjects. Results Inter-cone spacing measurements revealed a near-uniform cone density profile (ranging from 0.9–1.5 arcmin spacing) throughout the macula in ESCS. For comparison, normal cone density decreases by a factor of 14 from the fovea to 6°. Cone spacing of ESCS subjects was higher than normal in the fovea and subnormal beyond 2°. Compared to the control subjects ( n = 7), S-cone–mediated acuities in patients with ESCS were normal near the fovea and became increasingly supernormal with retinal eccentricity. Beyond 2°, S-cone acuities were superior to L/M-cone–mediated acuity in the ESCS cohort, a reversal of the trend observed in normal retinas. Conclusions Higher than normal parafoveal cone densities (presumably dominated by S-cones) confer better than normal S-cone–mediated acuity in ESCS subjects.

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Section: Discussionmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“… 40 The Z -score value of the cone spacing of each ROI was reported as standard deviations from a normal database at the measured eccentricity. 41 …”

Section: Methodsmentioning

confidence: 99%

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