Early-stage macular vascular and photoreceptor changes in DME

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Qinyuan Gu and Ting Pan and colleagues investigated the macular vascular and photoreceptor changes occurring in diabetic macular edema (DME) during the early disease stage and reported that vasospasm or vasoconstriction with limited further photoreceptor impairment were the first pathologic changes seen.¹

Gu and Pan are the first co-authors from the Department of Ophthalmology, The First Affiliated Hospital With Nanjing Medical University, Nanjing, China.

The researchers conducted a cross-sectional study from November 2021 to August 2022 that included 255 eyes of 134 patients with diabetes mellitus. All patients and underwent ophthalmologic and systemic evaluations. The patients were divided into 2 groups, ie, 69 patients with early DME and 65 patients without DME. The patients also underwent optical coherence tomography (OCT), OCT angiography, and adaptive optics scanning laser ophthalmoscopy, after which the eyes were classified as follows: early DME (114 eyes with central subfield thickness [CST] of 250 μm or more and less than 325 μm, an intact ellipsoid zone, and an external limiting membrane) and eyes without DME (141 eyes with CST less than 250 μm).

DME results

The authors reported, “The foveal avascular zone [FAZ] area of 0.3 mm2 or less (P < 0.001, odds ratio [OR] = 0.41, 95% confidence interval [CI] 0.26–0.67 in the multivariate analysis) and the hemoglobin A1c level of 8% or less (P = 0.005, OR = 0.37, 95% CI 0.19–0.74 in multivariate analysis) were associated significantly with a higher risk of development of early DME. No significant differences were seen in cone parameters between non-DME and early DME eyes.”

They explained further that compared with eyes without DME, vessel diameter, the vessel wall thickness, wall-to-lumen ratio, the cross-sectional area of the vascular wall in the upper side were significantly decreased in the early DME eyes (P = 0.001, P < 0.001, P = 0.005, P = 0.003, respectively).

The authors concluded that the primary macular vascular change at the onset of DME was a vasospasm or vasoconstriction with limited further glucose-associated photoreceptor impairment was present at the early stage of DME development. A CST of 250 μm or more and a FAZ of 0.3 mm2 or less may be the indicators for early DME detection and those parameters may be useful in screening.

Reference:

1. Gu Q, Pan T, Cheng R, et al. Macular vascular and photoreceptor changes for diabetic macular edema at early stage. Sci Rep. 2024;14:20544; https://doi.org/10.1038/s41598-024-71286-6