Relationship between peripapillary perfusion density, peripapillary flow index and traditional glaucoma measurements in open‐angle glaucoma and ocular hypertension: an optical coherence tomography angiography study

Abstract

PurposeThis study aims to detect peripapillary vascular changes in patients with glaucoma and ocular hypertension compared to healthy eyes, and to correlate these vascular parameters with structural and functional parameters.Methods46 open‐angle glaucoma eyes (GE), 35 ocular hypertension eyes (OHE) and 47 age‐matched control eyes (CE) were analyzed. Visual field test was performed with the Humphrey Field Analyzer 3. Optic disc region was imaged using a 4.5 × 4.5 mm scan by a HD‐OCT Cirrus. Peripapillary perfusion density (PPD) and peripapillary flow index (PFI) were quantified by the owner’s algorithm. The statistical analysis was performed using the Kruskal‐Wallis Test with Bonferroni Post Hoc analysis and Spearman rank correlation.ResultsGE showed an attenuated PPD globally and in each sector compared to OHE and CE (−10.62%), being the superior and inferior sectors the most affected ones. PFI in GE was also lower than those in OHE and CE (−14.43%). PPD and PFI were also lower in OHE than those in CE (p < 0.001 for all pairwise comparisons). Univariate regression analysis showed that PFI was correlated with retinal nerve fiber layer (RNFL) (r = +0.607) and visual field mean deviation (VFMD) (r = +0.586). PPD had a higher correlation with RNFL (r = +0.686) and VFMD (r = +0.609). Superior and inferior sectors were the most correlated (p < 0.001 for all).ConclusionsVascular changes that occur in GE can be visualized as reduced PPD and, specially, as PFI. This finding was not previously described, and suggests that the structural damage may be caused to a greater extent by a decreased PFI more than by an attenuation of PPD. Furthermore, OHE also exhibited vascular abnormalities compared with CE. This indicates that vascular changes may occur before changes in retinal thickness at the early stages of glaucoma. All of these measures resulted to be positively correlated with traditional glaucoma parameters. So, quantitative OCTA may have value in the future to evaluate or follow up glaucoma and ocular hypertension patients.