Novel Parameters to Assess the Severity of Corneal Neovascularization Using Anterior Segment Optical Coherence Tomography Angiography

Abstract

Assessment of anterior segment-optical coherence tomography angiography (AS-OCTA) to determine severity of corneal neovascularization (CoNV). Retrospective, cross-sectional, single-center study. Patients of various CoNV etiologies were selected and classified into mild, moderate, and severe. Their AS-OCTA images were measured for CoNV anterior limit, CoNV posterior limit, CoNV thickness, CoNV depth%, CoNV vessel density, CoNV area, and CoNV volume. Further, AS-OCTA parameters were correlated to clinical parameters, such as classification, a numerical severity scale, vascular clock hours, and best-corrected visual acuity (BCVA). A total of 19 mild, 10 moderate, and 6 severe CoNV eyes were included with no significant age-gender differences. CoNV depth% and volume increased from mild to moderate (9.3 ± 1.1% to 17.7 ± 3.3%, P= .030, and 0.2 ± 0.1mm3 to 1.0 ± 0.3mm3, P= .025, respectively) and from moderate to severe CoNV (44.6 ± 5.3%, P < .001, and 2.0 ± 0.3mm3, P= .014, respectively). CoNV area and posterior limit increased from mild to moderate (1.7 ± 0.3mm2 to 4.6 ± 0.7mm2, P= .001, and 217.7 ± 16.8μm to 349.1 ± 54.9μm, P= .048, respectively), not from moderate to severe (P= .999 and P= .403, respectively). CoNV thickness increased from moderate to severe (218.2 ± 46.6μm to 340.2 ± 8.7μm, P= .020), but not from mild to moderate. CoNV area and volume showed good correlations to CoNV staging (r= 0.703 and r= 0.771, respectively; P < .001) and severity scale (r= 0.794 and r= 0.712, respectively; P < .001). CoNV area showed good correlation to clock hours (r= 0.749, P < .001). CoNV depth and volume showed good correlation to BCVA (r= 0.744 and r= 0.722, respectively; P < .001). CoNV anterior limit and vessel density showed no significant correlations (P ≥ .05). Severe CoNV shows greater CoNV posterior limit, thickness, depth%, area, and volume on AS-OCTA compared to mild. CoNV volume and depth strongly correlate to BCVA. AS-OCTA provides novel, quantitative, and noninvasive parameters for assessing CoNV severity.