Correlation of outer retinal thickness with scotopic and photopic fundus-controlled perimetry in patients with reticular drusen

Abstract

Purpose : Reticular drusen represent a phenotypic hallmark in age-related macular degeneration (AMD). The aim of this study was to correlate outer retinal thickness with retinal sensitivity assessed by scotopic and photopic fundus-controlled perimetry in areas with reticular drusen (RDR) in the context of a cross-sectional, single-center, observational study

Methods : Twenty eyes from 18 patients (mean age 75.8 years) with RDR identified by confocal scanning laser ophthalmoscopy near infrared reflectance imaging and confirmed by spectral-domain optical coherence tomography and 20 eyes from 20 healthy controls (mean age 75.5 years) were included. Scotopic and photopic fundus-controlled perimetry (Nidek MP1S) was performed in patients. The localized 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.

Results : The mean outer retinal thickness in patients was 65.8 µm over areas with RDR and 76.4 µm (p<0.0001) over non-affected retinal areas. Photopic and scotopic sensitivity were reduced corresponding to areas with RDR (mean scotopic 12.8 dB and mean photopic 17.2dB ) as compared to non-affected retinal areas (18.2dB and 18.4dB) (p<0.001; p=0.001). On average a reduction of outer retinal thickness by 1 µm was associated with a decrease of scotopic function of 0.96 dB.

Conclusions : 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-mediated function. High-resolution retinal imaging in combination with scotopic fundus-controlled perimetry allows for a refined structure-function correlation in diseases with a presumed higher vulnerability of rod compared with cone function.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.