The effect of pilocarpine on contrast sensitivity in glaucoma patients

Purpose. To determine the effect of the miotic drug pilocarpine on contrast sensitivity in patients with glaucoma. Methods. Twenty-four patients who were either glaucoma patients or strong glaucoma suspects agreed to participate in the study. All subjects received a full slit lamp exanination with undilated ophthalmoscopy. Intraocular pressures were measured with the air-puff technique to minimize corneal epithelial disturbance. The subjects then received a full manifest refraction and contrast sensitivity measurements at either six or three feet with the VectorVision contrast sensitivity chart. The subjects then received one drop of 2% pilocarpine and waited 30 minutes. Manifest refraction and contrast sensitivity measurements were then repeated. ANOVA was then performed for each eye included in the study at each spatial frequency tested. Results. 22 right eyes and 21 left eyes were eligible for inclusion. For right eyes, a decrease in contrast sensitivity and log contrast sensitivity occured at 3, 12, and 18 cycles per degree that approached statistical significance (p=0.056) while 6 cycles per degree had no change. Left eyes had no change in contrast sensitivity. Conclusions. Pilocarpine can decrease contrast sensitivity. The absence of change for left eyes may have been due to patient fatigue.