This randomized controlled trial evaluated whether a single drop of 0.5% timolol maleate, administered before neodymium-doped yttrium aluminium garnet (Nd:YAG) laser posterior capsulotomy, reduced the rise in intraocular pressure compared with standard care alone. The study included adults aged 18-65 years who had developed posterior capsular opacification at least 3 months after cataract surgery and were scheduled to undergo Nd:YAG laser posterior capsulotomy. Participants were randomly assigned to receive either prophylactic topical timolol maleate or standard care without prophylactic timolol. Intraocular pressure was measured before the laser procedure and again 1 hour after the procedure by an ophthalmologist who was unaware of the assigned treatment. The study was based on the hypothesis that mean intraocular pressure 1 hour after posterior capsulotomy would be lower among participants who received prophylactic timolol maleate than among those who received standard care alone.