[A follow-up study on the intraocular pressure response of timolol eye drops (author's transl)].

In 22 open-angle glaucoma patients a total of 39 eyes were treated with Timolol 0.25% twice daily for an average period of 12.6 months. The relative intraocular pressure decrease at the beginning of the study was 47% of the untreated pressure level. This initial response declined to a 23% pressure decrease at the end of the study. In 8 eyes treatment had to be discontinued because of insufficient pressure control and in one patient because of subjective intolerance. In two patients (4 eyes) a complete loss of response of Timolol therapy was observed. The phenomenon of slowly diminishing drug effectiveness was not related to the untreated pressure levels in the patients covered by this study. In 5 eyes there was evidence of a rebound effect after discontinuation of Timolol therapy.