In two previous studies the effects of topically applied 1% and 0.2% solutions of bupranolol on intraocular pressure were investigated in 21 and respectively 20 eyes with chronic uncomplicated open-angle glaucoma.--As early as 30 minutes after both solutions a very significant pressure drop, without concomittant pupillary reaction, was recorded. The 1% bupranolol solution was less well tolerated and caused some ocular irritation. The present study was therefore initiated in order to find out whether a 0.2% solution of bupranolol would yield significantly different results in comparison with the former.--Statistical evaluation, based on variance analysis linked with multiple t-tests, showed a barely significant difference between the pressure-lowering effects of the 1% and 0.2% solutions after one hour, whereas after 2 hours the difference became clearly significant in favour of the 0.2% solution. Furthermore, the 0.2% solution clearly showed a tendency to prolonged duration of effect, beyond the two-hour observation time. It therefore seems justified to supplement the present findings by long-term studies aimed at assessing optimal concentrations of the drug on the one hand, and its long-acting properties on the other. In this way, bupranolol is likely to gain recognition as an antiglaucomatous agent.