*Correspondence, Alfredo Borgia: alfr.borgia@gmail.com

Purpose To describe vascular filling patterns in corneal neovascularization (CoNV) and evaluate the effect of corneal lesion location, CoNV surface area and multi-quadrant CoNV involvement on the filling pattern.

Methods Retrospective study of patients who had been investigated for CoNV using fluorescein angiography (FA) or indocyanine green angiography (ICGA) between January 2010 and July 2020. Angiography images were graded and analysed multiple independent corneal specialists. Corneal surface was divided into 4 quadrants and patient information was obtained through electronic records.

Results 133 eyes were analysed. Corneal lesions were located on the peripheral (72%) or central (28%) cornea. Central lesions were associated with multi-quadrant CoNV more frequently than peripheral lesions (p=0.15). CoNV located within the same quadrant of the corneal lesion was often first to fill (88.4%). In multi-quadrant CoNV, the physiological inferior-superior-nasal-temporal order of filling was usually respected (61.7%). Central lesions resulted in larger CoNV surface area than to peripheral lesions (p=0.09). In multi-quadrant CoNV, the largest area of neovascularization was also the first to fill in (peripheral lesion 74%, central lesion 65%).

Conclusion Fillings patterns in healthy corneas have previously been reported. Despite CoNV development, these patterns are usually respected. Several factors that may influence filling patterns have been identified, including corneal lesion location, CoNV surface area and aetiology of CoNV. Understanding filling patterns of neovascularization allows identification of areas at higher risk of developing CoNV, aiding in earlier detection and intervention of CoNV.