Distinguishing swept-source optical coherence tomography findings in active toxoplasmic retinochoroiditis

To define the swept-source optical coherence tomography (SS-OCT) features which distinguish ocular toxoplasmosis (OT) from other forms of retinochoroiditis.

This is a prospective diagnostic study enrolling 43 eyes of 43 patients with active toxoplasmic (TOXO) retinochoroiditis matched to 54 eyes (54 lesions) with non-TOXO retinochoroiditis evaluated by structural SS-OCT.

The finding of retinal hyper-reflective round deposits, sub-lesional choroidal thickening, and sub-lesional retinal pigment epithelium elevation were more likely to be found in TOXO lesions with a positive likelihood ratio of 45.2 (95% CI: 6.45-316.56), 23.86 (95% CI: 6.09-93.36), and 9.79 (95% CI: 4.22-22.7), respectively. The presence of each of these findings was associated with a high level for positive predictive value (PPV) (88.63-97.29), negative predictive value (NPV) (88.3-92.45), sensitivity (83.72-90.69), and specificity (90.74-98.14). Two-parameter model binary logistic regression suggested that sub-lesional retinal pigment epithelium elevation and sub-lesional choroidal thickening were significant predictors of the diagnosis of OT (Wald = 11.905, p < 0.001; Wald = 14.881, p < 0.001; respectively). By adding hyper-reflective round deposits along the posterior hyaloid or the retinal surface the model improved its performance with very good diagnostic accuracy with area under the curve (AUC) values of 0.96 (95% CI: 0.9-0.99) for two parameters model and 0.98 (95% CI: 0.93-0.99) for the three parameters model.

Our results show that three OCT findings including retinal hyper-reflective round deposits, sub-lesional choroidal thickening, and sub-lesional retinal pigment epithelium elevation are more likely to occur in OT patients as compared with non-OT patients.