Optic nerve changes in ocular toxoplasmosis

Purpose To determine the prevalence and features of the different types of involvement of the optic nerve in ocular toxoplasmosis. Methods Retrospective cross-sectional study. All patients with active ocular toxoplasmosis, consulting in the Uveitis Section of the Ophthalmology Department were selected. The involvement of the optic nerve was classified in the following categories: juxtapapillary retinochoroiditis, pure papillitis, neuroretinitis, distant lesion, and mixed lesion. Results The prevalence of involvement of the optic nerve found was 5.3%. The optic nerve involvement with the presence of a concurrent active distant lesion, occurred in 22 eyes (43.1%). A juxtapapillary lesion was found in 18 eyes (35.3%). Eight eyes (15.7%) presented lesions characterised as mixed. Isolated papillitis occurred in 3 eyes (5.9%). Forty-seven lesions (95.9%) were unilateral and two (4.1%) were bilateral. Twenty-eight eyes (54.9%) had pre-existing lesions and 23 (45%) were primary lesions. Visual acuity improved in 35 eyes (71.4%) and remained unchanged in 14 eyes (28.5%). Conclusion The involvement of the optic nerve most frequently found in ocular toxoplasmosis was optic nerve oedema with a concurrent distant active lesion. The second type of lesion most often found was juxtapapillary retinochoroiditis. Involvement was monocular in most cases and the visual prognosis was favourable.