Acute optic neuritis following infection with chikungunya virus in southern rural India

Objectives: To define acute optic neuritis following infection with chikungunya virus (CHIKV) and to determine the efficacy of treatment with corticosteroids of acute optic neuritis. Methods: This was an observational study involving 10 patients, who were confirmed cases of infection with CHIKV with acute optic neuritis in one or both eyes. A complete ophthalmic examination was performed in all cases. All 10 patients were treated with intravenous methylprednisolone for 3 days, followed by oral prednisolone for 2 weeks, thereafter reducing the dose of prednisolone over 1 month. Results: Of the 10 patients in the study, seven were male and three female. Seven patients had unilateral optic neuritis and three patients had bilateral optic neuritis. Initial visual acuity in the affected eyes ranged from perception of light to visual acuity of 6/6. After treatment, nine out of 10 patients improved to visual acuity of 6/12 or better. Color vision became normal in eight patients in our study. After treatment, a relative afferent pupillary defect persisted in four patients and six patients had normal pupils. A statistically significant improvement in vision was found after treatment (p <= 0.001). Visual field (HFA FF 120) examination showed various types of defect. Visual fields returned to normal in four patients, while the remaining six patients had persistent diffuse visual field defects. Conclusions: CHIKV infection may cause acute-onset of visual loss due to acute optic neuritis. Prompt recovery of vision may follow steroid therapy. Physicians should be aware of the possibility of acute optic neuritis following CHIKV infection so that a preventable cause of vision loss can be treated effectively. (C) 2010 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.