Microvasculature Thicknesses Can Reveal Central Visual Field Damage in Glaucoma

In eyes with advanced glaucoma, both superficial macular vessel density (MVD) and ganglion cell complex (GCC) thickness are significantly associated with central visual field (VF) damage, according to research published in the Journal of Glaucoma.

Researchers from the University of California, in San Diego, evaluated macular optical coherence tomography angiography (OCT-A) and 10-2 visual field sensitivity in 44 eyes from 44 patients (mean age: 72.4 years, 28 men, 16 women) with advanced glaucoma. They calculated regional and global VF mean sensitivity (MS) from total deviation plots. The investigators obtained superficial and deep MVD from 3×3 and 6×6 mm² OCT-A scans utilizing 2 sectoral definitions. They also used spectral-domain OCT to obtain macular GCC thickness simultaneously from the same scan as the MVD measurements. 

In each region of both scan sizes for both maps, the researchers found that lower MS was significantly associated with a decrease in superficial MVD and GCC. They note that associations were weaker in the individual sectors of the whole image grid compared with the Early Treatment Diabetic Retinopathy Study (ETDRS) map. The team also found that deep layer MVD was not associated with central MS. Although 6×6 mm² and perifoveal vessel density showed better associations with central 10 ̊ MS than GCC thickness (example R² from 25.7 to 48.1 μm and 7.8 to 32.5%, respectively), GCC thickness was more strongly associated with central 5 ̊ MS compared with MVD associations, according to the report. 

“Given stronger MVD- central 10° VF association compared to GCC, as well as stronger GCC- central 5° VF association compared to MVD, MVD and GCC are complementary measurements in eyes with advanced glaucoma,” according to the researchers. “Longitudinal analysis is needed to determine the relative utility of the GCC and MVD measurements.”

Study limitations include its cross-sectional design, limited sample size of patients, no evaluation of the potential confounding effect of anti-glaucoma drops, blood pressure-lowering medications, and systemic conditions on vascular measurements, and the absence of controls or a comparison group. Further, these findings may not be generalizable to other OCT-A vessel density or spectral domain OCT macular thickness measurements, and there is a possibility that the associations between structural and functional measurements differed in strength across the observed range of mean deviation among the cohort.

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

Ghahari E, Bowd C, Zangwill LM, et al. The association between regional macula vessel density and central visual field damage in advanced glaucoma eyes. J Glaucoma. Published online June 2, 2022. doi:10.1097/IJG.0000000000002055.