I read with interest the paper by Gedde and associates presenting the Tube versus Trabeculectomy Trial. One of the issues discussed was the number of glaucoma medications. At the first postoperative year, the number of antiglaucoma medications in the tube group was 1.3 ± 1.3 and in the trabeculectomy group was 0.5 ± 0.9 ( P < .001). These figures at the end of third year were 1.3 ± 1.3 in the tube group and 1.0 ± 1.5 in the trabeculectomy group ( P < .30). In the articles discussing this trial, one of the important points was the necessity for more glaucoma medications over the first year in the tube group.
Imaizumi and associates recommended assigning 1 point for each topical antiglaucoma medication and 2 points for oral acetazolamide. This seems rational because the effects of systemic carbonic anhydrase inhibitors are greater than those of the topical forms. In the case of fixed-combination antiglaucoma drugs, applying such a rule may be legitimate. For example, a patient in the tube group who received timolol and dorzolamide is comparable with another patient in the trabeculectomy group who received a fixed combination of timolol and dorzolamide. It is not logical to assign 1 point to each drop and then to compare the medications between groups. It has been demonstrated that the intraocular pressure reduction of fixed combination drugs has been greater or at least the same as simultaneous use of each component in separate bottles. It does not seem practical to depict and compare all medications between groups. Assigning 2 points for systemic and fixed-combination antiglaucoma medications sounds like a rational solution and may change the result of glaucoma medications in this trial.