Macular Neural and Microvascular Alterations in Type 2 Diabetes Without Retinopathy: A SS-OCT Study.

PURPOSE: To identify specific markers indicative of macular neural and microvascular alterations in individuals with Type 2 Diabetes Mellitus (T2DM) without clinically observable retinopathy.

DESIGN: Prospective cross-sectional study.

METHODS: Using the PLEX Elite 9000, all eyes underwent swept-source optical coherence tomography (SS-OCT) angiography. Quantitative analysis of acquired images compared macular neural and microvascular alterations in T2DM patients without retinopathy to age-matched controls. Precise assessments encompassed measuring the thickness of each individual retinal layer and evaluating macular vascular indices within different capillary plexuses.

RESULTS: Forty-nine T2DM patients and 51 age-matched controls participated. T2DM patients exhibited a significant reduction in the mean macular thickness of the ganglion cell-inner plexiform layer (GC-IPL) (82.5 ± 5.5 μm vs. 86.2 ± 5.0 μm, p = 0.001) and macular retinal nerve fiber layer (RNFL) (45.8 ± 3.0 μm vs. 48.1 ± 3.7 μm, p = 0.001). Furthermore, macular full retinal thickness was significantly lower in diabetic eyes than controls (324.9 ± 16.3 μm vs. 332.8 ± 13.7 μm, p = 0.009). Vascular measurements revealed subtle changes in macular vascular skeleton density within the total capillary plexuses in T2DM patients (0.132 ± 0.005 vs. 0.135 ± 0.005, p = 0.019).

CONCLUSIONS: Metrics derived from SS-OCT, particularly macular RNFL and GC-IPL thicknesses, emerged as superior indicators for the early detection of diabetic retinal disease in individuals with T2DM without clinically observable retinopathy. Further investigations are warranted to comprehensively understand the clinical implications of these findings.