Association Between Retinal Thickness as Measured by High Definition, Spectral Domain OCT and Dark Adaptation in Age-Related Macular Degeneration

Abstract

Purpose: : This study explored whether there is an association between retinal thickness and dark adaptation in older adults with varying degrees of age-related macular degeneration or normal retinal health.

Methods: : Participants were recruited through the department's retina and comprehensive care services. After pupillary dilation, dark adaptation (recovery of light sensitivity) was measured following an intense flash for a 1.7 degree diameter, 500nm target positioned at 5 degrees on the inferior vertical meridian. Retinal thickness was estimated using the Cirrus HD spectral domain OCT and its macular cube 512x128 protocol and research browser. Stereoscopic color 30-degree fundus photographs were taken with a FF450Plus camera and evaluated using the AREDS severity scale for AMD by trained graders masked to patient clinical and functional characteristics.

Results: : The sample consisted of 80 participants (M age 77 years, SD 8). Cone- and rod-mediated parameters of dark adaptation, signifying the rate of recovery of visual sensitivity over time, were estimated using a piecewise, nonlinear regression model. The slope representing the second component of rod-mediated dark adaptation was associated with retinal thickness in the regions within and adjacent to the psychophysically tested area (p < .05); those participants with thicker retina were more likely to have faster rates of rod-mediated dark adaptation.

Conclusions: : These results imply that there may be structure-function relationships in AMD that can be documented through the use of HD spectral domain OCT and dark adaptometry, an area deserving of further investigation.

Keywords: age-related macular degeneration • photoreceptors: visual performance • imaging/image analysis: clinical