Correlation of Partial Outer Retinal Thickness With Scotopic and Mesopic Fundus-Controlled Perimetry in Patients With Reticular Drusen

Abstract

To correlate partial outer retinal thickness with scotopic and mesopic fundus-controlled perimetry in patients with reticular drusen (RDR). Observational case series with controls of similar age. Twenty eyes from 18 patients with RDR (mean age 75.8 years) and 20 eyes from 20 healthy controls (mean age 75.5 years) were included. Scotopic and mesopic fundus-controlled perimetry was performed in patients. The localized partial outer retinal thickness at the site of test stimuli was determined as the distance between the outer border of the outer plexiform layer and the inner border of the ellipsoid zone and topographically corrected according to measurements in controls. The mean partial outer retinal thickness in patients was 65.8μm over areas with RDR and 76.4μm (P < .0001) over nonaffected retinal areas. Mesopic and scotopic sensitivity were reduced corresponding to areas with RDR (mean scotopic 12.8 dB and mean mesopic 17.2 dB) as compared to nonaffected retinal areas (18.2 dB and 18.4 dB) (P < .001, P= .001). On average, a reduction of partial outer retinal thickness by 1μm was associated with a decrease of scotopic function of 0.96 dB. The extent of outer retinal thinning in the presence of RDR is spatially associated with the extent of impairment in scotopic retinal function, indicating a direct structural-functional correlation of structural changes to loss of rod function. High-resolution retinal imaging in combination with scotopic fundus-controlled perimetry allows for a more refined structure-function correlation in diseases with a presumed higher vulnerability of rod compared with conefunction.