Imaging Characteristics and Clinical Utility of Half-Dose vs Full-Dose Ultra-Widefield Fluorescein Angiography.

PURPOSE: In early 2022, a fluorescein shortage occurred in the United States. To meet the standard of care for patients who required ultra-wide fundus fluorescein angiography (UWFFA), a regimen of half-dose (250mg) sodium fluorescein (10%) was adopted instead of the full-dose (500mg) at the Cole Eye Institute (CEI). In this paper, we compare the image quality, clinical utility, and the side effect profile of half-dose vs full-dose fluorescein in UWFFA for a cohort of stable patients.

DESIGN: Retrospective chart review.

SUBJECTS, PARTICIPANTS, AND/OR CONTROLS: Patients with retinal vascular disease were included if they received half-dose and full-dose UWFFA (Optos California, Dunfermline, UK) within 6 months at the CEI. Eyes were excluded if they received intraocular injections, laser procedures, new immunosuppression, and worsened or improved inflammation on clinical examination.

METHODS, INTERVENTION, OR TESTING: Quantitative assessment of vascular leakage was performed using a machine-learning enhanced automated segmentation platform. Leakage from late-phase UWFFA images was compared between half-dose and full-dose images. Qualitative assessment of image quality and relative vascular leakage was performed by 2 masked independent reviewers. Side effects after fluorescein administration were recorded for each patient.

MAIN OUTCOME MEASURES: Masked leakage grading and automated leakage scores.

RESULTS: There were 52 eyes of 35 patients, 42 (81%) uveitic, 5 (9%) diabetic, and 4 (8%) normal controls. Patients had no change to their visual acuity (LogMAR mean 0.3±0.6), anterior chamber and vitreous cell between UFFWA's. UWFFA images were deemed of equal quality and leakage by both masked reviewers (78-87% agreement, kappa 0.642). Automated leakage analysis showed mildly increased leakage in half-dose images overall (3.8% vs 2.8%, p=0.01), and in the macula (1.5% vs 0.6%, p=0.01). Side effects included nausea (half (n=3, 9%) vs full (n=2, 6%), p=0.69) and urticaria (n=0, 0% vs n=1, 2%, p=0.99) and were not different between doses.

CONCLUSIONS: In this cohort, half dose UWFFA produced images that were of similar quality, clinical utility and with a similar side effect profile compared to full dose. Half dose UWFFA can be used to accurately assess the retinal vasculature and could be used primarily as a method to save cost and prevent waste.