Researchers recently observed ganglion cell complex (GCC) thinning and macula vessel density decrease over time, regardless of the presence of glaucoma. However, in primary open angle glaucoma (POAG) eyes specifically, they found that the macula vessel density decreased faster than the GCC thinned and was associated with disease severity.

This prospective, longitudinal study evaluated 139 eyes (23 healthy, 36 pre-perimetric glaucoma and 80 POAG) of 94 patients who had at least three visits. Healthy eyes were followed for an average of two years and pre-perimetric glaucoma and POAG eyes for 2.6 years.

The team analyzed OCT angiography (OCT-A) vessel density and OCT structural thickness of the same 3×3mm2 GCC scan slab at each visit. They calculated and compared the rates of vessel density and thickness change within each diagnostic group. They also looked at the association between the rates of thickness and vessel density change and potential factors, including severity of disease and IOP.

The investigators discovered significant rates of GCC thinning and macula vessel density decrease in all diagnostic groups. In healthy eyes and pre-perimetric glaucoma eyes, they noted that the rates of GCC thinning and macula vessel density decrease were comparable.

In contrast, they detected a significantly faster rate of macula vessel density decrease in the POAG eyes than the rate of GCC thinning. In this group, they added that more than two-thirds of the eyes showed faster macula vessel density decrease than GCC thinning, with a significant association between faster macula vessel density decrease rate and worse glaucoma severity.

They concluded that the association between GCC thinning rate and glaucoma severity was not significant, while IOP during follow-up significantly affected the rate of GCC thinning in all groups but had no association with the rate of macula vessel density decrease.

“Macula vessel density is useful for evaluating glaucoma progression, particularly in more advanced disease,” the study authors wrote in their paper.

Hou H, Moghimi S, Proudfoot JA, et al. Ganglion cell complex thickness and macula vessel density loss in primary open angle glaucoma. Ophthalmology. January 13, 2020. [Epub ahead of print].