Toxocara optic neuropathy: clinical features and ocular findings

Abstract

We evaluated thirteen eyes of twelve patients diagnosed clinically and serologically with Toxocara optic neuropathy. Eleven patients had unilateral involvement and one patient had bilateral optic neuropathy. Eight patients (66.7%) had a possible infection source to Toxocara. Six patients (50%) had painless acute optic neuropathy. Ten eyes had asymmetric, sectorial optic disc edema with peripapillary infiltration and three eyes had diffuse optic disc edema. Eosinophilia was noted in five patients (41.7%) and optic nerve enhancement was observed in eight of eleven eyes (72.7%) with available orbit magnetic resonance imaging (MRI). Mean visual acuity significantly improved following treatment [mean logarithmic of the minimum angle of resolution (logMAR) 0.94±0.56 at baseline and 0.47±0.59 at the final (P=0.02)]. Asymmetric optic disc edema with a peripapillary lesion and a history of raw meat ingestion were important clues for diagnosing Toxocara optic neuropathy. Additionally, Toxocara IgG enzyme-linked immunosorbent assay (ELISA) test and evaluating eosinophil may be helpful for diagnosis.

Keywords: Toxocara optic neuropathy; ocular toxocariasis; optic neuropathy; toxocariasis.

Figure 1. Ocular features of Toxocara optic neuropathy patients

A: Fundus photograph of Case 1 at the initial presentation, asymmetric optic disc edema with peripapillary infiltrating lesion and chorioretinits are apparent; B: Optical coherence tomography cross-sectional image of Case 11, optic disc edema with subretinal fluid and vitreous opacity (white arrow) are apparent; C: Fundus photograph of Case 8 at the initial presentation, severe optic disc edema with macular lesions (retinal vasculitis, hard exudates, and severe macular edema) are apparent.