Timolol-Pilocarpine Combined vs Timolol and Pilocarpine Given Separately

Correspondence

Vol. 109, No.1

Reference 1. Heijl, A., Lindgren, G., and Olsson, J.: A package for the statistical analysis of visual fields. Doc. Ophthalmol. Proc. Ser. 49:153, 1987.

Timolol-Pilocarpine Combined vs Timolol and Pilocarpine Given Separately EDITOR:

In the article "Timolol-pilocarpine combined vs timolol and pilocarpine given separately," by M. B. SOderstrom, b. Wallin, P.-A. Granstrom, and W. Thornburn (Am. J. Ophthalmol. 107:465, May 1989), the authors state that the patients included in the study had intraocular pressures greater than 21 mm Hg after one week of timolol use. The baseline pressures before treatment with timolol, however, were not stated. The timolol effect appeared to be minimal, because the mean pressures on day 0 were high (27 to 28 mm Hg). If an additive effect is to be shown that warrants combined therapy, the timolol must be proven to be contributing to the hypotensive effect. Without information concerning the effect of timolol alone, this study may be documenting the effect of pilocarpine 4 % given three times daily as compared with twice daily. We are sure this information would contribute to the value of the study. ORNA GEYER, M.D. LEONARD ROTHKOFF, M.D. MOSHE LAZAR, M.D.

Tel Aviv, Israel _ _ _ _ _ _ _ Reply

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EDITOR:

The purpose of our study was to compare the effect on intraocular pressure of a solution

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containing timolol and pilocarpine with that of the two drugs given separately in patients not adequately controlled on a regimen of timolol alone. There was statistically significant additional pressure reduction in both treatment groups. Patients who fulfilled the admission criteria entered a one- to three-week baseline period (three weeks for previously untreated patients) and received a study bottle of timolol. We gave patients previously treated with timolol a baseline run-in because of the clinical impression that patients participating in clinical studies tend to be more compliant with their treatment. Several patients also failed to meet the inclusion criterion of an intraocular pressure greater than 21 mm Hg after the baseline period. Among the 80 patients included were 19 in whom diagnosis was recent and previously untreated. In this group, the prestudy mean intraocular pressure was 38 mm Hg. One reason for the high intraocular pressure was the predominance of patients with capsular glaucoma. After the baseline period with timolol therapy, the mean intraocular pressure was reduced to 29 mm Hg. The remaining 61 patients had been treated with timolol previously for varying periods of time. We do not believe that this group of patients responded differently to their timolol treatment because resistance to this drug is extremely rare. The additional pressure reduction caused by the pilocarpine is an additive effect.

MATS B. SODERSTROM, M.D. PER-ARNE GRANSTROM, M.D.

Huddinge, Sweden

ORlAN WALLIN, M.D.

Stockholm, Sweden

WILLIAM THORBURN, M.D.

Hudiksuall, Sweden