Intraocular angiostrongyliasis: clinical findings, treatments and outcomes.

Ocular angiostrongyliasis, diagnosed by identification of Angiostrongylus cantonensis in any part of the eye, is a very rare manifestation. We report seven cases of intraocular angiostrongyliasis in Srinagarind Hospital, Khon Kaen University, Thailand. From a total of 654 cases of angiostrongyliasis diagnosed between January 1995 and April 2005, 7 cases (1.1%) with ocular manifestations were found. Four men and three women were diagnosed, with a mean age of 32.1 years (range 21-46 years). All of the patients lived in the northeast of Thailand and acquired the infection by eating raw Pila spp. snails, the intermediate host of A. cantonensis. The incubation period lasted from 2 weeks to 2 months. The most common symptom, blurred vision without eosinophilic meningitis, occurred as a presenting symptom in five cases. The other two cases presented with eosinophilic meningitis prior to development of poor visual acuity. Both cases had papilloedema, neck stiffness and eosinophilia without fever. The visual acuity of the patient was mostly lower than 2/60 and, evidently, visual impairment in all patients was caused by retinal pigment epithelial defects. All cases had only one immature A. cantonensis worm in the eye, with the most common site being the intravitreous area. Several treatments, including oral prednisolone, topical prednisolone, argon laser, diode laser, Nd:YAG laser, surgical removal of the parasite and combination therapy, were used. There is no evidence that surgical and laser interventions improve the course of the disease, and both have associated risks. Visual outcome depends on the initial visual defects.