Progressive Ganglion Cell Complex Thickness and Vessel Density Loss in Healthy, Pre-perimetric Glaucoma and Primary Open Angle Glaucoma Eyes

Abstract

Purpose : Glaucomatous damage involves the macula neural tissue and microvasculature. This study aimed to characterize the change over time of ganglion cell complex (GCC) thickness and vessel density in healthy, pre-perimetric glaucoma and primary open angle glaucoma (POAG) eyes.

Methods : A total of 144 eyes (22 healthy eyes, 33 pre-perimetric glaucoma eyes, and 89 POAG eyes) were included from the Diagnostic Innovations in Glaucoma Study observational cohort study. Optical coherence tomography angiography(OCT-A) based superficial macula vessel density and OCT based GCC thickness were evaluated simultaneously at each visit during follow-up. Only eyes with more than 3 visits were included.The mean follow-up time and number of visits were 2.10 years and 3.50 visits for healthy eyes, 2.71 years and 3.82 visits for pre-perimetric glaucoma eyes, and 2.60 years and 3.84 visits for POAG eyes.The dynamic range-based normalized rates of vessel density and thickness change of the same 3×3 mm macula scan region were calculated and compared using mixed effects models. The association between the rates of change and baseline mean deviation (MD) was evaluated.

Results : Significant rates of loss of both GCC thickness and vessel density were detectable in all diagnostic groups (all P<0.05 comparing with 0 slope). In healthy eyes and pre-perimetric glaucoma eyes, the normalized age-adjusted rates of GCC thinning and vessel density dropout were comparable (all P>0.05). In contrast, the normalized age-adjusted mean rate (95% CI) of macula vessel density dropout (-2.82 (-3.36, -2.27) %/year) in the glaucoma eyes was significantly faster than GCC thinning (-1.28 (-1.49, -1.06) %/year, P<0.001). Faster vessel density dropout rate was significantly associated with worse baseline MD in glaucoma eyes (P=0.007), but the association between GCC thinning rate and baseline MD was not significant (P=0.520).

Conclusions : In this cohort, both GCC thinning and vessel density dropout over time were detectable in all 3 diagnostic groups. In POAG eyes, macula vessel density dropout is faster than GCC thinning and associated with POAG severity. This suggests that macula vessel density is a good option for monitoring of eyes with existing POAG.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.