Ultrasound biomicroscopy in peripheral retinovitreal toxocariasis.

Purpose: To report ultrasound biomicroscopic features in peripheral retinovitreal Toxocara uveitis.
Methods: Three patients with unilateral vitreitis suspected to be caused by peripheral toxocariasis were referred for ultrasound biomicroscopic examination of the peripheral retina, pars plana, and adjacent vitreous.
Results: In two of the three patients, characteristic pseudocystic transformation of the peripheral vitreous was seen. In both patients, Toxocara serology was positive and eosinophilia was present. In the third patient, no pseudocystic transformation of the peripheral vitreous was seen; however, there was the dense thickening adjacent to the pars plana usually seen by ultrasound biomicroscopy in pars planitis and corresponding to clinically visible snowbanks. The third patient had a negative Toxocara serology and later developed bilateral intermediate uveitis of the pars planitis type. In none of 48 patients with diverse inflammatory conditions of the retroiridal space that were examined by ultrasound biomicroscopy were the characteristic Toxocara-associated pseudocystic images seen.
Conclusions: Pseudocystic transformation of the peripheral vitreous appears to be a rather specific and sensitive ultrasound biomicroscopic sign in patients with presumed peripheral toxocariasis that will likely aid diagnosis in difficult cases.