Vitreoretinal morphology in active ocular toxoplasmosis: a prospective study by optical coherence tomography

To investigate the third generation optical coherence tomography (OCT3) findings in patients with active ocular toxoplasmosis.

A prospective observational case series, including 15 patients with active ocular toxoplasmosis in at least one eye evaluated at a single centre. Vitreoretinal morphological features at baseline and changes within a 24-week follow-up interval on OCT3 were evaluated.

The active ocular toxoplasmosis lesion was classified clinically as punctate (n = 6), focal (n = 6) or satellite (n = 3). Retinal layers were hyper-reflective at the active lesion site, and some degree of retinal pigment epithelium-choriocapillaris/choroidal optical shadowing was seen in all patients. In general, the retina was thinned at the active lesion site in eyes with punctate lesions and thickened in eyes with focal and satellite lesions. When detected by OCT3, the posterior hyaloid appeared thickened. While focally detached over punctate lesions, the posterior hyaloid was partially detached, but still attached to the lesion in focal and satellite lesions. Additional findings (not detected on clinical examination) include diffuse macular oedema (n = 6), vitreomacular traction (n = 3) and maculoschisis (n = 1). During follow-up, a decrease in retinal thickness and focal choriocapillaris/choroidal relative hyper-reflectivity were observed at the former lesion site, and posterior vitreous detachment progressed/occurred in all patients.

OCT3 enabled identification of morphological features underestimated on clinical examination in patients with ocular toxoplasmosis, which may expand the clinical spectrum of the disease. Further studies are needed to verify the relevance of OCT3 in assisting with the diagnosis and management of ocular toxoplasmosis.