Structural Retinal and Choroidal Changes in Toxoplasmic Retinochoroiditis Assessed by Swept-Source Optical Coherence Tomography

Purpose: To demonstrate retinal and choroidal structural changes across distinct disease activity phases in toxoplasma retinochoroiditis (TRC) using swept-source optical coherence tomography (SS-OCT) and establishing stage-specific imaging biomarkers for therapeutic decisions and monitoring. Methods: Retrospective analytical study of 33 patients (39 eyes) with TRC (2017–2024) at a tertiary uveitis clinic. Eyes categorized as active (n = 5), reactive (n = 13), or inactive (n = 27) using standardized clinical/serological criteria. SS-OCT measured central foveal thickness (CFT), subfoveal choroidal thickness (SFCT), retinal layers, and vitreous changes. Interobserver reproducibility assessed via intraclass correlation coefficients (ICC). Continuous parameters compared using Kruskal–Wallis H test with Dunn’s post-hoc correction. Multivariate logistic regression controlled for age, sex, lesion location, and bilaterality. Results: Mean age 25.4 ± 16.6 years (21 M:12F), 6 bilateral cases. BCVA improved from 0.67 ± 0.58 to 0.47 ± 0.42 logMAR (p < 0.05). Active eyes showed highest CFT (median 192 μm, range 95–420 μm), SFCT (median 412 μm), posterior hyaloid thickening (100%), vitreous hyperreflective dots (80%), and intraretinal/subretinal fluid (60%). Reactive eyes had intermediate thickness, RPE hyperreflectivity (84.6%), and outer retinal atrophy (92.3%). Inactive eyes demonstrated thinning, ellipsoid zone disruption (100%), RPE loss (100%), and epiretinal membranes (81.5%). Kruskal–Wallis: CFT H = 12.4, p = 0.002; SFCT H = 9.8, p = 0.007. Serous retinal detachment 17.9% (mostly active), no recurrence. ICC > 0.85 confirmed measurement reproducibility. Conclusions: SS-OCT reveals distinct structural signatures across TRC phases: active disease shows retinal edema and vitreoretinal disruption; reactive phases exhibit transitional remodeling; inactive disease manifests chronic atrophy. SS-OCT validates quantifiable disease staging, treatment monitoring, and prognostication. Future multimodal imaging studies needed.