The Impact of Age-Related Macular Degeneration (AMD) on the Retinal Layer Thickness Maps (RLTMs)

Abstract

Purpose : Average thickness of retinal layers was previously related to AMD, while layer damages are typically localized. We pointwisely associate the full RLTMs with AMD stage to take the spatial variation of layer thickness into consideration.

Methods : From a population-based study in Leipzig, we exacted the RLTMs from the machine-segmented Spectralis macular spectral domain optical coherence tomography scans for the 10 retinal layers (Fig. 1a) including retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), inner segment (IS), inner-outer segment junction (IS-OS), outer segment (OS) and retinal pigment epithelium (RPE). AMD stage graded based on the Rotterdam classification method was grouped into five stages: non-AMD, early AMD (drusen size < 125 μm), intermediate AMD (drusen size ≥125 μm), late dry AMD and wet AMD. One eye per subject was selected with the worse eye preferred. Pointwise partial correlations between the RLTMs and the AMD stage adjusted for age, gender and glaucoma diagnosis were calculated. P values were corrected for multiple comparisons.

Results : Among 1,625 eyes from 1,625 subjects (Age: 61.5 ± 10.8 years, 45.4% female), there were 537 non-AMD, 668 early/intermediate AMD, 55 late dry AMD and 365 wet AMD cases. Early/intermediate AMD (Fig. 1b) was most substantially associated with the GCL, OPL and IPL significantly affecting 24.2%, 13.0% and 8.6% of the scan region with extensive positive associations. No RPE regions were significantly correlated to early/intermediate AMD. Late dry AMD (Fig. 2a) was most substantially associated with the ONL, GCL and IPL with largely negative correlations and RPE with extensive positive correlations affecting 60.5%, 34.3%, 12.3% and 24.2% of the scan region, respectively. Wet AMD (Fig. 2b) was most substantially associated with the RPE (largely positive) and ONL (mainly negative in parafovea) significantly affecting 81.1% and 21.0% of the scan region, respectively. GCL and IPL were correlated with wet AMD in parafovea without statistical significance.

Conclusions : Thinner ONL, GCL and IPL were mostly associated with dry late and wet AMD, while the associations with dry late AMD were more substantial. Considerable areas of the RPE layer were significantly thicker in dry late and wet AMD except in early/intermediate AMD.

This is a 2020 Imaging in the Eye Conference abstract.

 

Fig. 1

 

Fig. 2