Abstract
Purpose :
While glaucoma following Boston keratoprosthesis (KPro) implantation is highly prevalent and aggressive, the underlying disease mechanism remains unclear. We performed an exploratory cross-sectional study evaluating optical coherence tomography angiography (OCTA) in patients with KPro and patients with primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) (without KPro) to characterize vascular pathology in KPro glaucoma.
Methods :
Patients with KPro, POAG and PACG underwent OCTA imaging with DRI OCT Triton, Topcon. Circumpapillary OCTA scans without significant artifacts were segmented from the internal limiting membrane to the retinal nerve fiber layer (RNFL). Two graders masked to diagnosis assessed microvascular defects and performed OCTA measurements in the images. The total angular circumference (α) of vascular defects relative to the ONH was measured. The vascular density (VD) and flow after large vessel removal were also measured. Continuous and categorical parameters were compared using Mann-Whitney U and Fisher’s exact test respectively.
Results :
3 KPro, 19 PACG, and 21 POAG eyes were included. All 3 KPro eyes demonstrated glaucomatous disease as evidenced by increased cup-to-disc ratio (CDR) and RNFL thinning. Subjects were similar in age and race (p > 0.38), although more PACG patients were female than POAG and KPro (64% vs 29% and 17%, p = 0.03). Structurally, PACG, POAG, and KPro glaucoma eyes had similar CDR and RNFL thickness (Table 1). Circumpapillary VD and flow measurements did not differ significantly between groups (Table 1). When assessing microvascular defect locations, all KPro glaucoma eyes had notable vascular defects in the inferior quadrant of the optic nerve head and lacked nasal defects (Figure). KPro glaucoma eyes demonstrated vascular defects with similar locations (p = 0.99 in all quadrants) and angular circumferences as POAG eyes (88 ± 20° vs 79 ± 60°, p = 0.27), while PACG eyes demonstrated wider vascular defects compared to the other groups despite similar mean deviation values on visual field testing (Table 1).
Conclusions :
Despite small sample size, KPro eyes with secondary glaucoma demonstrate focal vascular defects inferotemporally on OCTA that resemble POAG rather than PACG, supporting optic nerve vulnerability in KPro patients.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.