Deep-Layer Microvasculature Drop-Out Speeds Ganglion Cell Complex Thinning in Glaucoma

Ganglion cell complex thinning in primary open-angle glaucoma (POAG) occurs faster in eyes with deep-layer microvasculature drop-out (MvD) than in those without MvD, according to research published in the British Journal of Ophthalmology.

The investigators conducted a longitudinal study of patients with primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study who underwent optical coherence tomography angiography (OCT-A) to compare the rate of ganglion cell complex thinning with and without MvD. 

Patients with primary open-angle glaucoma from DIGS who had at least 1.5 years of follow-up and a minimum of 3 visits were included in the study. The researchers evaluated the area and angular circumference of MvD on en face choroidal vessel density images and horizontal B-scans. They also examined whether area, angular circumference, and location of MvD were associated with more rapid changes of the macular ganglion cell complex.

The study included 63 patients (with MvD: n=30 [36 eyes]; mean age 68.5 years; without MvD: n=33 [37 eyes]; mean age 70.5 years) who were followed for a mean of 3.3 years. The investigators found that MvD was localized in the inferotemporal region in 30 of 36 eyes with MvD. At baseline, the mean visual field mean deviation was similar between the 2 groups (P =.128). 

In time, global ganglion cell complex thinning was significantly faster in eyes with MvD than in those without MvD (mean difference, -0.50; 95% confidence interval, -0.83 to -0.17 μm/ year; P =.003). The presence, area, and angular circumference of MvD were each associated with a faster rate of global ganglion cell thinning (P =.002, P =.031 and P =.013, respectively). 

“Detection of MvD in OCT-A images can assist clinicians to identify patients who are at higher risk for central macula thinning and glaucomatous progression and may require more intensive management,” report the investigators.

Limitations of the study included measurement of MvD size on the en face choroidal vessel density map, exclusion of patients with advanced stages of glaucoma, possible inaccuracy in the automatic demarcation of en face images, use of the en face choroidal vessel density image to detect MvD, and potential ocular magnification effects associated with axial length in OCT-A measurement.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Reference

Micheletti E, Moghimi S, El-Nimri N, et al. Relationship of macular ganglion cell complex thickness to choroidal microvasculature drop-out in primary open-angle glaucoma Br J Ophthalmol. Published online January 13, 2022. doi:10.1136/bjophthalmol-2021-320621