Influence of a dilated pupil on the visual field in glaucoma.

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.