ObjectiveTo observe the clinical characteristics of adult patients with ocular toxoplasmosis (OT).MethodsThis study was a retrospective clinical trial. Among the 83 consecutive OT patients diagnosed in the Zhongshan Eye Center of Sun Yat-Sen University, 14 patients (16.9%, adult group) aged ≥18 years were included in the study from January 2017 to December 2019. A total of 14 OT patients (children group) aged less than 18 years who had consecutive visits from July to December 2019 were selected as controls. All patients underwent BCVA, slit lamp microscope, fundus color photography, and B-mode ultrasound examination. Eighteen cases underwent UBM examination, including 6 and 12 cases in the adult group and child group respectively; 23 cases underwent FFA examination, including 12 and 11 cases in the adult group and child group respectively. Snellen visual acuity chart was used for BCVA examination, which was converted into logMAR visual acuity in statistics. We compared the two groups of patients' residence (urban or rural), history of contact with dogs and cats, main symptoms, reasons for treatment, course of disease, and clinical and imaging characteristics and so on. For measurement data conforming to normal distribution, t-test was performed for comparison between groups; for Skewness distribution measurement data, rank sum test was performed for comparison between groups.ResultsCompared with the adult group and the child group, there was no significant difference in the canine-cat contact history (Z=2.661, P=0.257) and the time from first diagnosis to diagnosis (t=−0.186, P=0.351); compared with the children group and the adult group, the patient's living environment was mainly urban, and the course of disease was significantly shorter (Z=−2.005), and the difference was statistically significant (P=0.047). The logMAR BCVA of the adult group and the child group were 0.81±1.08 and 2.08±1.30, respectively, and the difference was statistically significant (Z=−2.811, P=0.004); compared with the child group, the adult group had lighter vitreous opacities, but the difference was statistical significance (Z=7.847, P=0.048). FFA examination revealed 20 cases of "fern-like" leakage of retinal capillaries. Among them, the adult group and child group were 10 (83.3%, 10/12) and 10 (90.9%, 10/11) cases respectively.ConclusionsAdult patients account for 16.9% of OT patients. Compared with children, adult patients mostly live in towns or cities, have a short course of disease, good vision at first diagnosis, and mild inflammation or hyperplasia of the vitreous cavity. FFA is helpful for the diagnosis of adult OT.