Two blind randomized cross-over trials in the treatment of primary open angle glaucoma.

We present the results of two blind randomized trials comparing both guanethidine 3 per cent and adrenaline 0.5 per cent (Ganda 3.0/0.5) and guanethidine 1 per cent and adrenaline 0.2 per cent (Ganda 1.0/0.2) in single drop form with Timolol (Timoptol) 0.25 per cent. Results of 48-hour phasing at the end of one month's treatment demonstrated a significantly greater fall in intraocular pressure with Ganda 3.0/0.5 (9.8 mm Hg) than with Timolol 0.25 per cent (7.67 mm Hg) P less than 0.001. There was no significant difference in the fall in intraocular pressure between Ganda 1.0/0.2 (8.87 mm Hg) and Timolol 0.25 per cent (8.24 mm Hg).