Peripapillary BMO-MRW Significantly Reduced in Early DR

The combination of BMO-MRW and OCT-A-derived microvascular metrics could potentially serve as early biomarkers for DR detection and progression monitoring. Photo: Julie Torbit, OD. Click image to enlarge. Studies have shown that retinal neurodegeneration takes place before microvascular changes are detected in diabetic retinopathy (DR) patients. Bruch’s membrane opening-minimum rim width (BMO-MRW) is a more sensitive indicator of neurostructural dam­age compared to retinal nerve fiber layer thickness (RNFLt), but it hasn’t been explored in DR patients. In a recent study, authors focused on the peripapillary optic disc region using BMO-MRW to assess nerve fiber changes and analyze the relationship between optic nerve thickness and microvascular alternations in these patients. They found a significant reduction in the superotemporal and inferotemporal quadrants, suggesting that BMO-MRW could potentially serve as a biomarker for DR detection and progression monitoring. The findings were reported in BMC Ophthalmology.Included in the study were 105 eyes from 105 diabetic patients, comprising 55 eyes without diabetic retinopathy (no-DR group) and 50 eyes with mild diabetic retinopathy (mild-DR group). An additional 50 eyes from 50 healthy individuals served as the control group. All eyes underwent OCT radial scanning to assess BMO-MRW and OCT angiography (OCT-A) with a 6x6mm scan centered on the optic disc to evaluate perfusion density and vessel density.Diabetic patients exhibited a significant reduc­tion in BMO-MRW, particularly in the superotemporal and inferotemporal quadrants. Declines in peripapillary perfu­sion density and vessel density were also observed, notably in the nasal, superotemporal and inferotemporal quad­rants. The positive correlation between BMO-MRW and both perfu­sion density and vessel density suggests a strong association between neuroretinal rim thinning and microvascular changes in early DR, according to the authors.“These findings underscore the potential of BMO-MRW and OCT-A-derived microvascular metrics as early biomarkers for DR detection and progression monitoring,” the authors wrote in their BMC Ophthalmology paper.Vascular analysis of the optic disc showed that in both the inner and outer rings, vessel density in the superior and inferior temporal quadrants was higher than in other quadrants, indicating a relatively richer blood supply in these regions. This “further contributes to an increased oxygen demand, potentially exacerbating their vulnerability to structural alterations under hyperglycemic conditions, as reflected by the observed BMO-MRW thinning,” the authors explained. “Notably, this change was not observed in perfusion density in the inner ring of the superotemporal and inferotemporal quadrants, whereas vessel density alterations were detected in the outer ring.”Using the ETDRS grid, the authors further analyzed BMO-MRW of the optic disc in six quadrants. In both the no-DR and mild-DR groups, BMO-MRW in the superior temporal and inferior temporal quadrants was significantly thinner than in the control group. This may be because the inner ring is anatomically closer to the BMO-MRW, leading to a stronger correlation.“The observed thinning of neural tissue and decreased vascular density in early DR suggest a potential relationship between neural tissue integrity and vascular density, reinforcing the concept of the “optic nerve vascular unit,”’ the authors explained in their article. “Diabetic patients without fundus lesions exhibit lower vessel density and perfusion density in the optic disc region than healthy individuals, indicating that optic disc vascular density could serve as an indicator of microvas­cular changes in diabetes.” Click here for the journal source.  Zhou J, Wang X, Lou W, et al. Peripapillary Bruch’s membrane opening-minimum rim width (BMO-MRW) and microvascular changes in early diabetic retinopathy. BMC Ophthalmol. April 28, 2025.