The use of optical coherence tomography angiography in differential diagnosis of conjunctival melanocytic tumors

Abstract

BACKGROUND: Optical coherence tomography angiography (OCTA) is a noninvasive method of eye microcirculation evaluation. Few reports are published on the use of OCTA for anterior segment (AS) vessels analysis in healthy eyes and in conjunctival tumors, and their vascular characteristics are still not thoroughly investigated. These questions are of importance, as it is known that tumors vasculature is indicative of the patients vital prognosis. AIM: The aim of our study was to investigate the potential of AS-OCTA in evaluation of normal conjunctival vessels architecture as well as that in melanocytic neoplasms. MATERIALS AND METHODS: 20 healthy volunteers (20 eyes) and 20 patients (20 eyes) with conjunctival nevi and melanomas were examined. AS optical coherence tomography (OCT) and AS-OCTA were performed. Scan analysis included qualitative assessment (vessels pattern, lumen, tortuosity) and quantitative assessment [perfusion density (PD, %) index]. Mean (MPD), maximum (MaxPD) and perifocal PD (PPD) were determined. RESULTS: In normal group, predominantly radial pattern of the vessels was revealed, their caliber remaining the same along their entire length; larger vessels were more often discovered in deep conjunctival layers. The lowest PD value (29.9%) was registered in the inferior conjunctival segment, and the highest (36.7%) in the nasal one. In the conjunctival tumors area tortuosity of the vessels, uneven vessels caliber along their length, and increase in the PD value were observed. Melanomas were characterized by an increase in the lace-like pattern and by presence of confluent pattern zones; MaxPD value was more than 50%. Significant difference was found between MPD values of normal conjunctiva and MPD values in conjunctival melanoma. CONCLUSIONS: AS-OCTA is an informative method for the visualization of vessels in normal conjunctiva and in conjunctival tumors. If the tumors vessels are unevenly distributed, MaxPD should be measured.