Influence of a dilated pupil on the visual field in glaucoma

Abstract

Purpose: The author studied the effects of pupillary dilation on perimetry in a group of glaucomatous patients receiving timolol therapy.

Patients and methods: A prospective study compared the visual fields of 23 patients with primary open-angle glaucoma of varying severity (mean defect: 3.84; short-term fluctuation: 1.91; pattern standard deviation [SD]: 3.61; corrected pattern SD: 3.12) before and after instillation of phenylephrine 10% using the Octopus 1-2-3 projection perimeter (INTERZEAG AG, Schlieren, Switzerland).

Results: The mean defect became impaired by an average of 3.01 (SD +/- 1.52) dB after administration of phenylephrine (p < 0.001). The pattern SD and the corrected pattern SD also became impaired with dilation by 1.51 dB (p < 0.01) and 1.73 dB (p < 0.05), respectively, after dilation. These changes varied across the visual field. The outer zone of the visual field had the greatest impairment after dilation with phenylephrine.

Conclusions: Pupillary dilation in patients with glaucoma produces a nonuniform decrease in threshold sensitivities that is statistically greater on outer zone of the visual field.