Authors: Arshia Eshtiaghi, Tina Felfeli, Felicia Tai, Jess Rhee, Kira Dzulynsky, Michael Kryshtalskyj, Hatim Batawi, Nupura Bakshi, Larissa Derzko-Dzulynsky.
University of Toronto.
Author Disclosure Block: A. Eshtiaghi: None. T. Felfeli: Funded grants or clinical trials; Name of for- profit or not-for-profit organization(s); Fighting Blindness Canada, Vanier Canada Graduate Scholarship, Canada Graduate Scholarship-Masters, the Vision Science Research Program, Postgraduate Medical Education Research Award. Funded grants or clinical trials; Description of relationship(s); Grant, Grant, Grant, Grant, Grant. F. Tai: None. J. Rhee: None. K. Dzulynsky: None. M. Kryshtalskyj: None. H. Batawi: None. N. Bakshi: None. L. Derzko-Dzulynsky: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); AbbVie, Novartis, Allergan. Any direct financial payments including receipt of honoraria; Description of relationship(s); Financial Support, Financial Support, Financial Support.

Abstract Body:
Purpose: To characterize optical coherence tomography (OCT) features in patients with idiopathic
intermediate, posterior, or panuveitis.

Study Design: Retrospective case series.

Methods: All consecutive cases of idiopathic intermediate, posterior, or panuveitis at four tertiary care centres between 2010 and 2021 were identified. Clinical and a comprehensive set of OCT features including presence of macro- and microstructural changes such as intraretinal fluid (IRF), epiretinal membrane (ERM), subretinal fluid (SRF), chorioretinal folds, pigment epithelial detachment (PED), vitreomacular adhesion (VMA), central macular thickness (CMT), and en-face abnormalities were collected at the baseline and last follow-up. The en-face OCT segmentations were performed manually at the IS/OS slab in order to detect areas of hyper or hypo-reflectivity on dynamic video OCT imaging. All OCTs with poor signal quality (<5/10) were excluded from analysis.

Results: A total of 57 patients (96 uveitis eyes) were followed for an average duration of 30±23 months. Fifty-six percent of patients were female, and the mean age of patients was 44 (SD: 16) years. Uveitis was unilateral in 32% of patients, and bilateral in 68%. Twelve percent of patients had an acute course of uveitis, 60% had chronic uveitis, 21% had recurrent uveitis, and 7% had an unspecified course. With regards to anatomical classification, 46%, 7%, 7% and 40% were intermediate, posterior, both intermediate and posterior uveitis, and panuveitis, respectively. Systemic immunomodulatory therapy was initiated in 81% of patients. The mean visual acuity in uveitic eyes was 0.43±0.6 logMAR
(Snellen:20/54) at baseline and 0.28±0.5 logMAR (Snellen:20/38) at last follow-up. The median CMT was 284μm at baseline and 270μm at last follow-up. At baseline and last follow-up, respectively, 23% and 18% of uveitic eyes had IRF, 12% and 0% SRF, 42% and 56% ERM, 3% and 6% chorioretinal folds, 0% and 0% PED, and 8% and 3% VMA. Additionally, abnormalities on en-face were noted in 32% and 16% of cases at baseline and last follow-up, respectively. Throughout the follow-up period, approximately 72% of eyes had at least one of the aforementioned OCT abnormalities.

Conclusions: Structural abnormalities on OCT imaging were notable in a large proportion of eyes with idiopathic intermediate, posterior, and panuveitis at baseline and throughout follow-up. With initiation of treatment, the IRF improved over time while the number of cases with ERM increased amongst our patient population.