The patient was a 50-year-old man who reported blurred vision and floaters in the right eye that persisted for about 6 months. He then consulted a local ophthalmologist. He was diagnosed with panuveitis and referred to our department. There was no previous ophthalmic history and his general health was good. He had a 10-year history of contact with dogs, but no history of ocular trauma. On presentation, the best-corrected visual acuity (BCVA) in the affected eye was 20/25, and the ocular pressure was normal. Results of slit lamp examination showed inflammatory cells (2+) and infiltration in the anterior chamber of the right eye. The fundus examination showed (1+) vitreous opacities, (2+) vitreous cells, phlebitis, moderate disc swelling, reddening, yellowish-white retinal lesions in the inferotemporal region of the optic disc, and a white exudative lesion near the inferior arcade (fig. 1a). The left eye was normal. Fluorescein angiography showed a hyperfluorescent lesion and dye leakage from the middle to late phases with a hyperfluorescent optic disc. Peripheral blood tests, including blood cell count, erythrocyte sedimentation test, C-reactive protein, and serum angiotensin converting enzyme, were within the normal ranges. Serum toxoplasma antibody and viral antibodies were negative. Chest X-rays were normal. No signs suggested endogenous uveitis, and no clinical findings suggested uveitis due to tuberculosis or syphilitic, fungal, or viral infection. Examination of the patient's serum for antibody to T. canis larvae by ELISA showed an elevated antibody level (fig. 2).
Based on characteristic funduscopic findings, a diagnosis of ocular toxocariasis was made. Systemic albendazole (ALBENZA , GlaxoSmithKline, Brentford, UK) (800 mg twice daily) was prescribed with oral steroids (initial dose 30 mg/day), which resulted in the resolution of the vitreous opacity. However, the lesion near the arcade seemed to be white and enlarged. It was alleviated because the exudative lesion was dried out with treatments after 1 month (fig. 1b). However, 3 months after treatment initiation, the toxocariasis recurred during a treatment-free period (fig. 1c). In addition to the primary lesion, 2 other yellowish-white retinal lesions with vitreous flares appeared. Anthelmintic albendazole (ALBENZA 800 mg twice daily) and oral steroids (initial dose 20 mg/day) were resumed, and the infectious lesions were controlled gradually after another 2 months (fig. 1d). The BCVA in the right eye improved to 20/12.5. Two months after the retreatment was terminated, an intraretinal lesion was observed protruding from the retinal surface into the vitreous cavity (fig. 3a). Examination of this site by HP-OCT confirmed an elevated lesion protruding from the inner retina to the vitreous cavity (fig. 3e). The lesion was in the inner retinal layer, and the retinal pigment epithelium (RPE) and choroid were intact. The anthelminthic medication (800 mg twice daily) was resumed, and the elevated lesion resolved on OCT within the following 8 months (fig. 3b, f). One year after the therapy, signs of inflammation and the elevated retinal lesion had disappeared along with the reduction of blood anti- Toxocara canis antibody titer (fig. 2). Unexpectedly, after 4 months, the elevated lesion reappeared (fig. 3c, g) and anthelmintic monotherapy (800 mg twice daily) was resumed, resulting in lesion control after 2 months (fig. 3d, h). The patient was subsequently treated with anthelminthic drug and steroid tapering. At the last examination after 21 months of follow-up, the BCVA was 20/12.5 with no evidence of active inflammation. The patient continues to be followed untreated without complications.