Diabetes Could Influence Glaucoma Patient Microvascular Density

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Retinal nerve fiber layer density also appears to be influenced by presentation of both conditions.

The pathology of diabetes mellitus may play an integral role in the microvascular density of patients with primary open-angle glaucoma (POAG), according to new data presented at the American Academy of Ophthalmology (AAO) 2020 Virtual Meeting.

In new data from a cross-sectional study conducted by a team of US-based investigators, findings indicate diabetes mellitus pathology could associate with POAG density within superior and nasal quadrants.

Led by study author John Yu Cheng, BA, investigators sough to evaluate the quantitative characteristics associated with radial peripapillary capillary (RPC) vascular plexus in the eyes of glaucoma patients with or without diabetes.

Their assessment included optical coherence tomography angiography (OCT-A), correlating observed associated changes with retinal nerve fiber layer (RNFL) thinning as seen on tomography.

Their assessment included 44 eyes from as many patients. Patient eyes were split between primary open-angle glaucoma only (n = 26) and diabetes/POAG eyes (n = 18), and were scanned using OCT-A and OCT RNFL.

Patient diabetes was defined as HbA1c levels greater than 6.5%. Cheng and colleagues conducted their assessment using the two-way ANOVA with post-hoc Tukey honest significant difference (HSD).

Eyes of patients with diabetes and POAG showed a decreased mean microvascular density versus those with lone POAG (P <.01). An assessment of RPC in 4 quadrants also showed patients with diabetes and POAG have reduced mean density versus lone POAG patients in nasal (34.2% vs 40.3%) and superior (34.1% vs 40.8%) quadrants (P <.05).

A sub-analysis of RNFL on OCT in 4 quadrants also showed a difference in the thickness of RNFL between both patient groups (P <.01). Investigators observed a “moderate correlation” in RNFL loss among patients with both diabetes and POAG to have a dropout in microvascular density.

“Our results indicate diabetes pathology may act on the microvasculature density of primary open-angle glaucoma patients in a synergistic manner within superior and nasal quadrants,” investigators wrote.

The study, “Effects of Type 2 DM and POAG on Peripapillary Microvasculature Density and Nerve Fiber Layer,” was presented at AAO 2020.