Multimodal Imaging and Longitudinal Trajectory Analysis of Recurrent Ocular Toxoplasmosis and Contralateral Early-Onset Cataract: An Observational Analytic Case Study

Background: Ocular toxoplasmosis is the leading cause of infectious posterior uveitis. A dense cataract in an otherwise quiet fellow eye creates a clinical dilemma between bilateral parasitic dissemination and an independent coexisting disorder. Objective: To characterize the longitudinal structural and functional trajectories of recurrent ocular toxoplasmosis with contralateral early-onset cataract and to assess whether the two conditions were causally related. Methods: This ethically approved longitudinal observational analytic case study followed a 37-year-old woman from baseline to week 6. Assessments included visual acuity, tonometry, B-scan ultrasonography, fundus photography, spectral-domain optical coherence tomography, and serological assays. Result: At baseline, right-eye vision was light perception because of an isolated mature grade 4 cataract without signs of uveitis, whereas the left eye had 6/18 vision with active juxtafoveal retinochoroiditis and a peripapillary scar. Anti-Toxoplasma gondii IgG was reactive (393.4 IU/mL) and IgM was nonreactive. After phacoemulsification and intraocular lens implantation, right-eye visual acuity reached 6/6 by postoperative day 3, and imaging revealed a pristine neuroretina with a central macular thickness of 219 μm. Oral trimethoprim-sulfamethoxazole followed by tapered methylprednisolone consolidated the left retinochoroidal lesion and restored 6/6 vision by week 6. Conclusion: Marked interocular asymmetry in ocular toxoplasmosis requires multimodal structural verification. In this patient, the contralateral early-onset cataract represented independent coexistence rather than bilateral parasitic causality.