Topographic correlation of retinal layer thickness with mesopic and scotopic fundus controlled perimetry in early and intermediate age-related macular degeneration

Abstract

Purpose : To analyze the thickness of different retinal layers in eyes with early and intermediate age-related macular degeneration and to topographically correlate findings to both scotopic and mesopic retinal sensitivity using fundus-controlled perimetry (FCP).

Methods : Twenty-nine eyes of 26 AMD patients (mean age 71.2 years, range 54.5-83) and 29 eyes of 29 healthy controls (“normals”) underwent optical coherence tomography raster scanning (Spectralis, Heidelberg Engineering, Heidelberg, Germany). Mesopic (Goldmann III) and scotopic (Goldmann V, 200 msec, 4-2 strategy) FCP (MP-1 S Nidek, Technologies, Padova, Italy) was performed using a 56 test stimuli grid in patients. Topographic analysis of the thickness of the total retina, the inner retina (iR), the outer nuclear layer (ONL), the photoreceptors (PR) and the retinal pigment epithelium (RPE, including drusen material in patients) at the site of retinal sensitivity test stimuli was conducted. In patients, localized thickness of these layers was correlated to both mesopic and scotopic retinal sensitivity.

Results : RPE/drusen complex thickening in patients was correlated with reduction of ONL (p<0.0001), iR (p<0.0001) and PR thickness (p<0.0001), while changes in retinal thickness were more pronounced in the central 4° compared to eccentric macula (p=0.021). Structural changes in thickness of all layers were correlated with reduction of both mesopic (p<0.001) and scotopic retinal sensitivity (p<0.001).The odds ratio for a localized reduction of 5 dB and 10 dB in the presence of a localized RPE/drusen complex thickening of more than 2 standard deviations from normal values was 4.1 (95%CI: 3.1 – 5.4) and 7.2 (4.3 – 12.1) for mesopic and 2.6 (2.0 – 3.6) and 5.3 (4.0- 7.2) for scotopic testing, respectively (p< 0.001).

Conclusions : Accumulation of sub-RPE material in patients with intermediate AMD is spatially confined to quantifiable structural alterations in various retinal layers as well as corresponding functional impairment. The topographic analysis of retinal thickness and retinal sensitivity will be helpful for a better understanding of disease mechanisms and for the evaluation of new therapeutical strategies.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.