Anterior Segment OCTA of Melanocytic Lesions of the Conjunctiva and Iris.
To study the feasibility and diagnostic value of vascular imaging using OCT-Angiography (OCTA) of melanocytic lesions of the conjunctiva and iris. Design; Cross-sectional study.Twenty-five patients with an untreated conjunctival lesion (5 melanoma, 13 nevus, 7 primary acquired melanosis (PAM) and 52 patients with an untreated iris lesion (10 melanoma, 42 nevus) were included. Patients were imaged using a commercially-available OCTA device, with addition of an anterior segment lens and manual focussing. Tumor vessel presence, vascular patterns and vascular density were assessed.Good OCTA images were obtained in 18/25 conjunctival lesions, and 42/52 iris lesions. Failure was caused by lack of patient cooperation, an unfavorable location, or mydriasis. In all imaged conjunctival lesions, and 77% of iris lesions, vascular structures were detected. Conjunctival melanoma and nevi demonstrated the same intralesional tortuous patterns, while vasculature in eyes with PAM was similar to normal conjunctiva. Both iris melanoma and nevi demonstrated tortuous patterns, distinct from the radially-oriented normal iris vasculature. Good quality images were related to light pigmentation, good cooperation, and (for conjunctival lesions) a bulbar rather than caruncular location. There were no differentiating patterns or differences in vascular density between nevi and melanoma of the conjunctival or iris.OCTA allows for non-invasive imaging of the vasculature in melanocytic lesions of the conjunctiva and iris. Good image quality depends highly on patient cooperation and lesion characteristics. Differentiation of benign and malignant lesions was not possible. New software is called for to improve image acquisition and analysis.