Intraocular pressure and visual field defects after argon laser trabeculoplasty in chronic open-angle glaucoma

Nineteen patients undergoing argon laser trabeculoplasty for open-angle glaucoma were studied prospectively. All patients had glaucomatous visual field defects with inadequate medical control of intraocular pressure (IOP) before laser treatment. All patients had two automated visual fields immediately before laser treatment. They also had follow-up automated perimetry at 1, 4, 8, and 12 months posttreatment. The serial visual fields were compared using a one-way analysis of variance and trend analysis. After the laser trabeculoplasty, six patients showed visual field improvement, eight showed no change, and five showed progressive visual field deterioration. Patients with little fluctuation of IOP measurements after laser treatment had a better prognosis for visual field retention. The mean IOP level, however, was a poor predictor of visual field progression. Patients with more extensive visual field damage before laser treatment did not do worse than patients with less extensive visual field loss.