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A comparison of the effects of betaxolol, timolol, and pilocarpine on visual function in patients with open-angle
1Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
Purpose:
The author compares the effect of betaxolol, timolol, and pilocarpine on visual functions in patients with glaucoma.
Methods:
Sixty-eight patients with early glaucoma were randomly allocated to betaxolol, timolol, or pilocarpine treatment and their visual fields, motion detection, and contrast sensitivity were studied over a 24-month period. A subset of the betaxolol and timolol group were also followed with short-wave automated perimetry. One eye of each patient was used in the analysis.
Results:
All three drugs reduced pressure effectively. Pilocarpine and timolol were not significantly different from each other and both produced a more marked pressure reduction than betaxolol. There were no significant differences between the drugs on the visual fields, contrast sensitivity, or motion detection. Betaxolol appeared to have a better impact on the blue-yellow sensitivity of the upper nasal and upper temporal visual field quadrants than timolol.
Conclusions:
In spite of a greater pressure reduction, timolol did not have a more favorable effect on visual function. In the short-wave automated perimetry, the betaxolol did marginally better than timolol. The apparent dissociation between pressure reduction and protection of visual function deserves further study.