Changes in inner retinal thickness in age-related macular degeneration (AMD) detected using a grid-wise analysis of optical coherence tomography scans.

Abstract

Purpose : To determine if changes in the outer retina of individuals with age-related macular degeneration (AMD) lead to changes in the inner retina through a grid-wise analysis for macular optical coherence tomography (OCT) scans for the ganglion cell and other inner retinal layers.

Methods : OCT macular cube scans (61 B-scans covering an area of 30° × 25°) of 51 eyes from 51 patients with intermediate AMD (65% female, 52-79 years old) were acquired with Spectralis spectral domain OCT at the Centre for Eye Health, Sydney, Australia. Scans were automatically segmented into individual retinal layers using the HRA/Spectralis Viewing Module, reviewed and manually corrected if necessary. Macular thickness of the ganglion cell layer (GCL), inner nuclear layer (INL) and inner plexiform layer (IPL) were then extracted as 64 measurements across an 8 × 8 grid centered on the fovea (each grid location covering 0.74mm²). Thickness measurements were compared against an age-matched normative database (n = 96) and a significant difference was considered as measurements which were 2 standard deviations away from mean normal thickness.

Results : 74.5% of the subjects exhibited a significant deviation in GCL thickness in at least one grid location in the macula: 39.2% exhibited GCL thickening, 19.6% exhibited GCL thinning, and 15.7% exhibited both thinning and thickening. For the INL, majority of the subjects exhibited thickening (31.6%) rather than thinning (10.5%). For the IPL, the majority of the subjects exhibited thinning (57.9%) than thickening (5.3%).

Conclusions : Subtle but significant changes in GCL, IPL and INL thickness can be detected in AMD eyes in vivo using a detailed, grid-wise OCT analysis. These changes, particularly in the IPL may reflect potential synaptic anomalies which require further investigation.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.