Swept-source OCT-angiography (OCT-A) was better able to delineate iris vessels in normal pigmented irises compared with spectral-domain OCT-A, a recent study reported.

This prospective study included 10 patients with normal pigmented irises and five eyes with iris neovascularization (NVI). Each of the participants underwent imaging, which two masked observers graded for visibility, artifacts and NVI characteristics.

The researchers observed a paired mean difference of iris vessel density measurements of 11.7, with swept-source OCT-A detecting more vessels than spectral-domain OCT-A. They noted that the inter-grader reliabilities for artifact score and visibility score were substantial. The team added that both systems were able to detect NVI vessels with a fair amount of agreement, with clearer NVI characteristics in stages one and two compared with stage three of NVI.

“Both anterior segment OCT-A systems identified NVI characteristics based on its atypical configuration or location, but further improvements are needed to allow for more accurate objective, serial quantification for clinical use,” the study authors concluded in their paper.

Ang M, Devarajan K, Tan ACS, et al. Anterior segment optical coherence tomography angiography for iris vasculature in pigmented eyes. Br J Ophthalmol. August 18, 2020. [Epub ahead of print].