Assessment of swept source optical coherence tomography angiography metrics in uveitis with vascular leakage on ultrawide field fluorescein angiography

Abstract

Purpose : Ultrawide field fluorescein angiography (UWFFA) is used to assess leakage and disease activity in uveitis patients. Swept-source optical coherence tomography angiography (SS-OCTA) allows for non-invasive measurement of vascular metrics, but its utility in assessing disease activity in active uveitis is unknown. This study aims to evaluate the utility of SS-OCTA as an imaging modality for determining change in vascular leakage in patients with uveitis.

Methods : Patients were enrolled in a prospective IRB-approved study assessing the effect of the injectable fluocinolone acetonide implant (FAi) on imaging metrics in patients with uveitis (PANTHER, NCT #04340505). Imaging studies were performed on these patients pre- and post-treatment, including FA, OCT, and SS-OCTA. UWFFA were analyzed by a semi-automated algorithm to quantify the area of leakage. Patients with improvements in leakage on UWFFA had their corresponding 6x6mm SS-OCTA scans analyzed (Zeiss Macular Density v1.0) to quantify the total area and total length of vessels in the superficial and deep vascular plexuses. The pre and post treatment SS-OCTA metrics were compared. One-tailed Mann-Whitney U tests were used for statistical analysis.

Results : 10 eyes from 8 patients treated with the FAi were included with a mean age of 60 years (range: 33-77). The pre-treatment average leakage on UWFFA was 4.13 ± 1.67%, decreasing to 0.89 ± 0.51% post-treatment. Average total vessel area on SS-OCTA pre-treatment (Superficial: 41.21 ± 1.84%; Deep: 29.83 ± 3.49%) was not found to be significantly (p > 0.05) different to average total vessel area post-treatment (Superficial: 39.72 ± 2.02%; Deep: 26.57 ± 3.58%). Similarly, average total vessel length on SS-OCTA pre-treatment (Superficial: 22.65 ± 1.07 mm^-1; Deep: 17.17 ± 2.43 mm^-1) was found to be not significantly (p > 0.05) different to average total vessel length post-treatment (Superficial: 21.89 ± 1.21 mm^-1; Deep: 14.91 ± 2.47 mm^-1).

Conclusions : SS-OCTA metrics did not correlate with leakage metrics on UWFFA in patients with uveitis treated with the FAi. There were minimal change in SS-OCTA metric in patients who had significant changes in leakage on UWFFA and on clinical exam. Although SS-OCTA is non-invasive and can provide perfusion metrics, these do not appear to correlate with known measures of disease activity in uveitis patients.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.