Is the Use of Refrigerated Fixed Combination of Dorzolamide 2%-Timolol 0.5% (COSOPT) Associated with Less Ocular Discomfort: A Pilot Study.

Purpose: To test the hypothesis that the use of refrigerated fixed combination of dorzolamide 2% plus timolol 0.5% solution (COSOPT) is associated with less ocular discomfort compared with the use of this solution kept at room temperature.

Methods: In this prospective comparative study, 30 primary open-angle patients and 30 healthy subjects filled in the questionnaire on symptoms (Ocular Surface Disease Index) and subjective stinging feeling scale (1-10), at the start of study and 30 days after continuous use of refrigerated fixed combination or placebo eye drops. Results were processed by applying the methods of descriptive (arithmetical mean, standard deviation) and analytical statistics for evaluation of significance of the difference (Student's t-test).

Results: Ocular discomfort parameters were significantly lower after the use of refrigerated fixed combination of dorzolamide 2% plus timolol 0.5% solution (t-test, P < 0.0001). Breakup time, Schirmer 1 test, and intraocular pressure values did not differ.

Conclusions: The use of refrigerated fixed combination of dorzolamide 2% plus timolol 0.5% (COSOPT) solution is associated with less ocular discomfort than the use of the same fixed combination at room temperature.