Danit G. Saks, Angela Schulz, Ayub Qassim, Bronwyn Ridge, Ryan Pham, Samran Sheriff, Ting Shen, Vivek Gupta, Jamie E. Craig, Stuart L. Graham

Purpose: To identify retinal vascular changes in primary open angle glaucoma including vessel density (VD), vascular wedge defects and foveal avascular zone (FAZ).

Methods: A total of 548 eyes from 304 suspect or mani- fest glaucoma participants (age=67.02 ± 10.37 years) and 60 eyes from 44 healthy controls (age=62.43 ± 8.21 years) were imaged using optical coherence tomography (OCT) and angiography. Superficial vascular complex (SVC) and deep capillary plexus scans were exported to ImageJ for analysis of VD; presence and nature of vascular wedge defect, including correlation with retinal nerve fibre layer (RNFL) defect and wedge VD; and FAZ parameters (n=200 suspect/manifest glaucoma eyes and 60 control eyes), including area, perimeter and circularity. All relevant statistics controlled for sex, age, OCT angiography system and OCT angiography scan quality.

Results: Superficial VD was significantly lower (p = 0.003) and deep VD was not significantly different in glaucoma eyes vs controls (p = 0.420). There were 81 eyes found with vascular wedge defects (15% of suspect/ manifest glaucoma eyes), visible only at the SVC, with no vascular wedges found in controls. VD within the wedge was approximately 3 4 of macula SVC VD. Vascular wedges corresponded with visible RNFL wedges, but not all RNFL wedges corresponded with vascular wedges. All FAZ parameters were significantly higher in suspect/ glaucoma eyes than control eyes (p < 0.001) other than circularity which was significantly lower (p < 0.001). Conclusions: While the vascular contribution to the aetiology of glaucoma is still being established, this study characterises vascular alterations found in glaucoma including vessel density, unique vascular wedge defects and enlarged foveal avascular zone.