Objective:To compare the clinical manifestations of ocular toxoplasmosis (OT) in adult and children, and to preliminarily explore the role of intraocular fluid detection in the early diagnosis of OT.Methods:A retrospective study. From January 2018 to October 2019, 60 cases of OT patients with 60 eyes diagnosed in the Department of Ophthalmology of Beijing Chaoyang Hospital Affiliated of Capital Medical University were included in the study. The medical history information of patients was collected in parallel with slit-lamp microscopy, indirect ophthalmoscope examination, and canine toxoplasma antibody detection in aqueous or vitreous fluid. Fifty-eight cases underwent visual inspection; 2 cases did not underwent visual inspection, who were children. The visual acuity examination was carried out using the new version of the standard logarithmic visual acuity chart, which was converted into the logarithmic minimum angle of resolution(logMAR) visual acuity during statistics. According to age, the patients were divided into adult group and child group, with 12 eyes in 12 cases and 48 eyes in 48 cases, respectively. The clinical characteristics and main points of diagnosis and treatment of the two groups of patients were compared and observed. The comparison among the measurement data groups conforming and the normal distribution was performed by the independent t test. The comparison between the measurement data groups of the skewed distribution was performed by the Kruskal- Wallis test. The qualitative data were compared with χ 2 test. Results:Among the adult group and the child group, 7 (58.3%, 7/12) and 34 (70.8%, 34/48) patients with a clear history of contact with dogs and cats were in the adult group and the child group, respectively. The adult group was significantly lower than the child group, however, there was no different statistical significance ( χ 2=0.236, P=0.627). At the first visit, the self-reported blurred vision of the adult group and the child group was 10 (83.3%, 10/12) and 22 (45.8%, 22/48) cases, respectively. In the adult group and the child group, 3 (25.0%, 3/12) and 20 (43.5%, 20/46) eyes with logMAR visual acuity greater than 1.85, 8 (66.7%, 8/12) and 22 (45.8%, 22/46) eyes with logMAR visual acuity less than 0.3. The visual acuity of the adult group was better than that of the child group, and the difference was statistically significant ( Z=2.162, P=0.031). There was no statistically significant difference in the composition ratio of different clinical types of the two groups of eyes ( χ 2=1.908, P=0.385). The incidence of inflammation in the anterior segment of the eye in the adult group and the child group were 25.0% (3/12) and 56.3% (27/48), respectively; there was no statistically significant difference between the two groups ( χ 2=3.750, P=0.053). The concentration of antibodies in the vitreous humor of the affected eye in the adult group and the child group was greater than that of aqueous humor. The antibody concentrations of vitreous humor and aqueous humor were 36.51 (22.58) and 19.94 (21.78) U/ml in the children group; 45.95 (56.44) and 32.20 (38.64) U/ml in the adult group. Comparison of antibody concentrations in the vitreous humor and aqueous humor of the affected eyes in the child group showed statistically significant differences ( Z=-1.984, P=0.047). Conclusions:Compared with children with OT, adult patients with OT have better vision and mild inflammation or hyperplasia of the vitreous cavity. The detection of antibodies related to toxoplasma in the intraocular fluid is helpful for early diagnosis.