Surgery for nonarteritic anterior ischemic optic neuropathy.

BACKGROUND: Nonarteritic ischemic optic neuropathy is characterized by sudden and painless loss of vision in one eye, accompanied by pallid swelling of the optic disc. Although various medical interventions, such as corticosteroids and phenytoin sodium, have been used to treat nonarteritic ischemic optic neuropathy, no therapy has been proven effective. OBJECTIVES: The objective of this review is to assess the safety and efficacy of surgical treatment compared with other treatment or usual care in people with nonarteritic ischemic optic neuropathy. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register - Central and MEDLINE. The most recent searches were performed in December 1997. SELECTION CRITERIA: We included randomized trials comparing surgery to no surgery in people with nonarteritic ischemic optic neuropathy. DATA COLLECTION AND ANALYSIS: We obtained full copies of all potentially relevant articles. Only one article described a randomized trial of surgery and it was eligible for inclusion. No formal assessment of quality was done. One reviewer extracted data. No synthesis was required, as there was only one trial. MAIN RESULTS: The one trial identified randomized 258 patients. The only published report with outcomes data for that trial presents preliminary results from 244 patients who had achieved six months of follow-up at the time of the report. Participants assigned to surgery did no better than participants assigned to careful follow-up regarding improved visual acuity of three or more lines of vision at six months: 32.6% of the surgery group improved compared with 42.7% of the careful follow-up group. The adjusted odds ratio (OR), adjusted for baseline visual acuity and diabetes, comparing the two groups for three or more lines improvement was 0.74 (95% confidence interval (CI) 0.39 to 1. 38) (surgery group improvement was worse than careful follow-up). In addition, participants receiving surgery had a significantly greater risk of losing three or more lines of vision at six months: 23.9% in the surgery group worsened compared with 12.4% in the careful follow-up group. The six-month adjusted OR comparing the two groups for loss of three or more lines of vision was 1.96 (95% CI 0.87 to 4.41). Spontaneous improvement of three or more lines of vision was observed in 42.7% of participants in the careful follow-up group. REVIEWER'S CONCLUSIONS: Results from the Ischemic Optic Neuropathy Decompression Trial indicate that optic nerve decompression surgery for nonarteritic ischemic optic neuropathy is not effective.