A 7 year prospective comparative study of three topical beta blockers in the management of primary open angle glaucoma

Aim - To determine the long term efficacy of monotherapy with topically app lied beta blocking agents and to determine whether selective beta blockers were able to preserve the visual field more effectively than nonselective a gents. Method - A prospective randomised, open, comparative study of three topical ly applied beta blockers-timolol, betaxolol, and carteolol-was carried out on 153 patients (280 eyes) with newly diagnosed open angle glaucoma. Those patients who were not withdrawn were followed by the same observers for a m inimum of 2 years and a maximum of 7 years, with clinical observations, Gol dmann tonometry and 24.2 Humphrey visual field analysis. Results - All three drugs lowered the IOP significantly from untreated leve ls but betaxolol took up to 12 months in some instances to reach the maximu m pressure reduction. After 7 years only 43% of the eyes begun on timolol, 34% of those started on carteolol, and 29% of those on betaxolol were still being treated with these medications alone. Visual fields were analysed th roughout the trial by CPSD and MD and at the end by linear regression analy sis (PROGRESSOR). The visual fields remained the same without apparent impr ovement or deterioration throughout the period of follow up. Eight patients (11 eyes) were withdrawn because of continuing field loss in spite of redu ction in IOP (six using carteolol and five using betaxolol). Conclusions - Analysis shows that less than half the eyes initially treated with topical beta blockers might be expected to still be being treated wit h their original medication after 5 years. The rest required either additio nal medication or trabeculectomy. There was no statistically significant im provement or deterioration in the visual fields over a 7 year period. On th e evidence of this trial there are no particular advantages in using select ive blockers.