Age-controlled correlation between oral glucose tolerance test (OGTT) and thicknesses of ten retinal layers in non-diabetes and prediabetes participants from macular optical coherence tomography (OCT) volume scans

Abstract

Purpose : People with prediabetes are at higher risk of developing diabetes. We investigate the age-controlled relationship between glucose parameters and ten retinal layer thicknesses in optical coherence tomography (OCT) macular volume scans of non-diabetic and prediabetic participants with/without glaucoma in a large study. The fasting, 30-min, and 2-h plasma glucose (FPG, 30-min PG, and 2-h PG) during an oral glucose tolerance test (OGTT) were employed.

Methods : All eyes of non-diabetic and prediabetic participants with available OGTT and OCT scans from the population-based, sex- and age-stratified LIFE-Adult study (age range: 20-80) were included. Macular volume scans (97 horizontal B-scans with 512 A-scans each) from Spectralis OCT were automatically segmented into ten layers (Figure 1) after exclusion of unreliable B-scans (quality < 20 dB). Pointwise partial Pearson correlation during OGTT adjusted for age was calculated. The analysis was repeated excluding participants with self-reported glaucoma diagnosis or medication.

Results : Figure 2 visualizes the age-controlled correlation of glucose level and A-scans in each layer from 5532 eyes of 2787 participants, including 128 participants with glaucoma. For FPG, a predominantly negative correlation (red) with layer thicknesses of RNFL, ONL, and MZ and a positive correlation (blue) with EZ and OS were observed (Figure 2A). Similar correlation patterns were found for 30-min PG with layer thicknesses of RNFL, MZ, and EZ, with a slightly increasing negative correlation with layer thicknesses of GCL and IPL (Figure 2B). For 2-h PG, there is an apparent negative correlation with layer thicknesses of GCL, IPL, and MZ (Figure 2C). The correlation patterns remained unchanged when participants with glaucoma were excluded.

Conclusions : There were specific correlation patterns between retinal layer thicknesses and measures during OGTT. With the prolongation of the time post-glucose intake, higher glucose level was more clearly related to thinner GCL and IPL and firmly associated with thinner MZ, while the correlation with RNFL, ONL, EZ, and OS became less pronounced. Macular layer thicknesses could be an early indication of the retinal structural change prior to diabetes and in this cohort did not seem to be impacted by comorbidity of glaucoma.

This is a 2021 ARVO Annual Meeting abstract.