Comparative Analysis of the Thickness of Inner Retinal Layers among African Immigrants Based on Their Status of Glucose Tolerance

Inner retinal neurodegeneration was found, independent of the severity of retinopathy in persons with diabetes (DM). However, it is unknown whether the inner retinal neurodegeneration is evident in people with prediabetes (preDM) or asymptomatic people with newly diagnosed DM. In this cross-sectional study, we prospectively enrolled African immigrants who self-identified as being healthy with no prior history of diabetes. Each participant was tested for diabetes with an OGTT and underwent a comprehensive eye exam with spectral-domain optical coherence tomography and stereoscopic fundus photographs. The thickness of parafoveal (PA) retinal nerve fiber layer (RNFL), perifoveal (PE) RNFL, PA ganglion cell + inner plexiform layers (G+I), and PE G+I were measured using an automated segmentation software. A total of 211 African immigrants enrolled in the study. After excluding participants with a history or signs of glaucoma and other conditions that could affect retinal structural integrity, there were 21 DM participants (76% male, age 46 (28-61y) (mean (range))), 72 preDM participants (61.1% male, age 42.4 (23-65)), and 91 normal glucose tolerant (NGT) participants (58% male, age 36 (20-62y)). From the 91 NGT control subgroup, 52 age-sex-matched participants were selected for comparative analyses (64% male, age 43 (32-62y)). Among participants in the 3 subgroups (DM, preDM, NGT), there was no significant difference in the mean thickness of PA RNFL (24.7 (2.4) (mean (SD)), 24.9 (2.1), 24.6 (2.8), respectively, P=0.863), PE RNFL (35.9 (3.8), 36.7 (4.1), 35.4 (3.2), P=0.794), PA G+I (88.8 (5.6), 90.6 (10.3), 89.7 (7.2), P=0.415), or PE G+I (65.0 (5.0), 67.2 (5.6), 67.4 (4.2), P=0.194). With this limited sample size, we were unable to find in fircan an association of neurodegeneration in persons with PDM and NDM. Future studies with larger sample size may provide further supporting evidence for such an association. Disclosure C.K. Hwang: None. E. Agron: None. A.E. Sumner: None. S.M. Briker: None. J.Y. Aduwo: None. C. DuBose: None. E. Chew: None.