Abstract: Objective To investigate the clinical and imaging features of toxoplasmic retinochoroiditis. Design Retrospective case series. Participants Six cases (6 eyes) with toxoplasmic retinochoroiditis patients in Beijing Tongren Hospital from Aug. 2017 to Sep. 2022. Methods Best corrected visual acuity (BCVA), slit lamp ophthalmoscopy, indirect ophthalmoscopy, fundus fluorescein angiography (FFA), indocyanine green fundus angiography (ICGA) and optical coherence tomography (OCT) were undergone. Goldmann-witmer coefficient and PCR assay in the ocular fluid were also recorded. All patients were treated with systemic antibiotics and corticosteroids for 4~6 weeks and followed up for 2~24 months. Main Outcome Measures Features of the fundus, FFA, ICGA and OCT. Results All patients had unilateral onset. The fundus showed a single and active focus with yellow-white focal retinochoroiditis, accompanied by vitritis. Two of the 6 cases had retinal vascular white sheath and 1 had an old lesion. Lesions in 4 cases were located in the posterior pole, while 2 were in the nasal mid-periphery. Three of the 6 cases had inflammation in anterior chamber. Lesion sizes ranged from (0.5×0.5) PD to (3.0×4.0) PD. The BCVA of the affected eye ranged from counting fingers to 0.5. The lesion appears as hypofluorescent or slightly hyperfluorescent in the early phase and showed varying degrees of fluorescence leakage in the late phase on FFA. Five cases had retinal vascular leakage and 4 had hyperfluorescence leakage of the optic disc in late stage. The lesions were consistently hypofluorescent on ICGA. OCT showed that lesions in 4 cases involved the entire layer of the retina, which were thickened and hyperreflective. Meanwhiles, choroid was thickened and single hyporeflective choroidal nodule could be found. The remaining 2 cases showed localized retinal thinning, and the inner retinal layer was collapsed with cavities. All 6 patients had macular epiretinal membrane or epiretinal membrane, including 1 case with vitreomacular traction. All 6 patients showed reduced activity of lesions after treatment, and no recurrence was observed during the follow-up period. Conclusion The typical presentation of toxoplasmic retinochoroiditis is a unilateral, focal yellow-white lesion in posterior pole with vitritis. OCT shows involved the entire layer of the retina with the possibility of choroidal nodules. Clinical and imaging examinations can effectively diagnose the typical cases. (Ophthalmol CHN, 2023, 32: 202-207)

Key words: ocular toxoplasmosis, toxoplasmic retinochoroiditis