Abstract
Purpose :
Contrast sensitivity (CS) has been reported to be related to structural changes of photoreceptors in patients without media opacities. The horizontal length of the intact ellipsoid zone in eyes with retinitis pigmentosa (RP) is correlated with the logCS (Yioti GG, 2012). We examined whether the CS is significantly correlated with the parafoveal cone density measured by an adaptive optics scanning laser ophthalmoscope (AO-SLO) in normal subjects and patients with retinal degeneration.
Methods :
Fifteen normal subjects (mean age, 26.1±4.5 years) and 11 patients with retinal degeneration; 4 cone dystrophy, 2 occult macular dystrophy, 1 super normal b-wave, and 4 retinitis pigmentosa (age, 35.1±15.9 years) who did not have media opacities and had visual acuities of 20/60 or better were examined. The CS was measured by CSV-1000HGT with full correction. The cone mosaic was photographed with a custom-built AO-SLO (Topcon) at 1×1 degrees angle of view centered at the fovea. The CS was converted to the logarithm (logCS) and the area under the logCS function (AULCSF) was calculated. The parafoveal cone density was calculated in concentric rings with a radius between 0.38 degrees and 0.43 degrees from the fovea in which cones were well resolved by AO-SLO.
Results :
The logCS with 12.0 and 18.0 c/d was significantly and positively correlated with the parafoveal cone density in the normal subjects (P<0.05). The logCS with 3.0 and 6.0 c/d was significantly and positively correlated with the parafoveal cone density in the retinal degeneration group (P<0.05). The AULCSF and the parafoveal cone density in the retinal degeneration group were significantly lower than that in the normal group (P<0.001).
Conclusions :
Our results demonstrated that the logCS is significantly correlated with the parafoveal cone density in normal subjects and patients with retinal degeneration. The degree of decrease of the CS in patients with photoreceptor degeneration can be predicted from the cone density determined by AO-SLO if patients do not have media opacities.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.