Purpose: To evaluate the role of transvitreal optic neurotomy in the treatment of nonarteritic anterior ischemic optic neuropathy, a scleral outlet compartment syndrome, in which neurovascular compression at the prelaminar and laminar regions of the optic nerve head may play a major role.
Methods: Seven eyes of seven selected patients with severe vision loss (<20/800) from nonarteritic anterior ischemic optic neuropathy underwent transvitreal nasal radial optic neurotomy. The study was not masked and not randomized. Visual acuity and visual fields, when possible, were measured, and fluorescein angiography was performed preoperatively and postoperatively.
Results: Four male and three female patients had a mean age of 52.4 years; five had bilateral disease. The mean follow-up was 13 +/- 7 weeks. Mean preoperative visual acuity was 20/2400; mean postoperative visual acuity was 20/250, with an average of 10 lines of improvement. Six of seven patients showed visual improvement. One patient had peripapillary choroidal neovascularization. In two patients with sufficient visual acuity, preoperative visual fields could be obtained; these patients showed significant improvement in postoperative perimetry. Five patients had some loss of vision, which made it impossible to obtain preoperative visual fields.
Conclusion: Relaxation of the scleral ring of the prelaminar and laminar regions of the optic nerve head reduces constriction and may prevent necrosis of salvageable but underperfused nerve fibers. Despite improvement of visual acuity in our patients, transvitreal optic neurotomy should be considered experimental, requiring a randomized clinical trial.