Clinical and Ophthalmic Biomarkers of Diabetes Mellitus: A Longitudinal Study of Visual Outcome

Abstract

Purpose : Diabetic retinopathy is the leading cause of blindness in the working age population, and vision loss may be irreversible if the disease is not detected and treated early. Vision loss manifests as microvascular retinal changes, including microaneurysms, basement membrane thickening, pericyte loss, and abnormal neovascularization, which can be visualized through optical coherence tomography (OCT) and angiography (OCTA). In this study, we examined clinical laboratory biomarkers, ophthalmic biomarkers from OCTA and OCT, and visual acuity data to analyze predictable biomarkers for visual acuity outcomes.

Methods : A population of patients with diabetes mellitus (218 eyes) and healthy controls (95 eyes) were prospectively included. OCT/OCTA images were analyzed by a custom MATLab script for six vessel parameters and detailed phenotyping of these patients was performed by retrospective data analysis. Visual acuity of diabetic patients were obtained and analyzed from their initial visit (2014-2018) throughout their clinical care to their most recent follow up visit (2020-2022).

Results : Longitudinal evaluation over 7 years revealed that the majority of patients had relatively stable visual acuities. Cluster map analysis revealed that elevated hyperglycemia and evidence of renal failure were more common in those with moderate to severe diabetic retinopathy. Optic disc and macular thickness on OCT and vascular parameters on OCTA correlated with severity of diabetic retinopathy and can be found even in those without clinical evidence of diabetic retinopathy based on examination and fundus color imaging. Vascular analysis using OCTA of the superficial capillary plexus revealed significant correlation of neurodegeneration of the unmyelinated optic nerve axon with 3 vascular parameters (vessel flux, vessel area density, and vessel complexity index) in the superior and inferior peripapillary quadrants – the areas most significantly affected in DM.

Conclusions : Hyperglycemia and renal dysfunction were correlated with worsening diabetic retinopathy severity. Ophthalmic imaging revealed that neurodegeneration was present even before patients presented with symptoms. Early screening for diabetic retinopathy is crucial to detect microvascular changes, which can help improve clinical diagnosis, treatment, and vision loss before retinal microvascular changes become irreversible.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.