Abstract
Purpose :
Glaucoma is known as neurodegenerative disease with a vascular component. Retinal microcirculation was observed to be impaired even in early glaucoma stages, visualized and quantified by OCT-angiography (OCT-A). Peripapillary OCT-A scans are challenging for analysis as vessel density (VD) is dependent on demarcation of the optic disc. Thus, it was the aim of the present study to investigate APSified Bruch’s membrane opening (BMO)-based peripapillary VD of glaucoma with and without visual field loss compared to controls.
Methods :
Peripapillary OCT-A scans of 115 participants were acquired using Heidelberg Spectralis II: ocular hypertension (OHT; n=20), pre-perimetric open-angle glaucoma (pre-OAG; n=9), OAG (n=35), and controls (n=51). Mean vessel density (VD) was computed for each of the four sectors (superior, inferior, nasal, temporal) and for the whole scan using the Erlangen AngioTool, enabling an APSified and BMO-based analysis. For the statistical analysis of mean and sectorial VD, an ANCOVA and a linear mixed model were used respectively. The diagnosis was set as a fixed effect and gender and age as covariates. For sectorial VD the sectors were embedded as repeated measures and a random intercept was added additionally to the model.
Results :
Mean VD correlated significantly with diagnosis (p=0.00018) and age (p=0.00013), but not with gender (p>0.05). Moreover, the pairwise comparison showed, that there were significant differences between mean VD of OAG and controls (p<0.0001) and OHT and pre-OAG (p=0.016), yet not for the other groupings (p>0.05). For sectorial VD, diagnosis (p=0.00018), age (p=0.00013) and sector (p<E-11) correlated significantly, while gender did not (p>0.05). Looking at the pairwise comparisons of the diagnosis per sector revealed, that in each sector again the difference between sectorial VD of OAG and controls (p<0.0003) or pre-OAG and OHT (p=0.016) correlated significantly, respectively. No significant differences were observed between primary and secondary OAG (p>0.05).
Conclusions :
Peripapillary microcirculation was observed to be impaired in perimetric glaucoma eyes and even in early glaucoma stages, yet not in OHT. As previous analysis of macular VD yielded a significantly reduced VD in OHT eyes, we assume that either analysis of peripapillary VD as to be enhanced further on, or the involvement of vascular alterations in glaucoma pathogenesis has a more peripheral origin.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.