The Prophylactic Effect of Dexmedetomidine 0.008% Versus Brimonidine 0.2% on IOP Elevation After Nd: YAG Laser Capsulotomy.

Posterior capsule opacification (PCO) is a common post-cataract surgery complication treated with Nd:YAG laser posterior capsulotomy, which may cause intraocular pressure (IOP) spikes and threaten vision. Brimonidine and apraclonidine are widely used to prevent such elevations. This prospective, double-masked, randomized clinical trial evaluated the efficacy of topical dexmedetomidine, a novel ophthalmic drop, in preventing IOP rise after Nd:YAG laser treatment. A total of 111 eyes from 89 pseudophakic patients were randomized to receive dexmedetomidine 0.008% or brimonidine 0.2% one h before the procedure. Patients with glaucoma, baseline IOP > 24 mmHg, keratoconus, corneal edema, prior refractive/corneal surgery, or unstable cardiovascular disease were excluded. IOP was measured with air-puff tonometry at baseline, 30 min, 4 h, and 24 h post-laser. Baseline characteristics were comparable. In the dexmedetomidine group, mean IOP values were 16.3 ± 3.6, 14.8 ± 4.7, 17.1 ± 6.2, and 16.7 ± 4.5 mmHg, while in the brimonidine group, they were 16.7 ± 2.9, 13.3 ± 3.9, 13.2 ± 5.5, and 14.2 ± 3.9 mmHg, respectively. At 30 min, brimonidine significantly reduced IOP (p = 0.000), whereas dexmedetomidine did not (p = 0.116). At 4 and 24 h, IOP increased above baseline with dexmedetomidine but decreased with brimonidine (p = 0.001 and p = 0.004). Dexmedetomidine was associated with more IOP spikes > 10 mmHg (9% vs. 2%, p = 0.035) and IOP > 30 mmHg (7% vs. 2%, p = 0.09). No systemic or ocular side effects occurred. Although dexmedetomidine prevented acute IOP surges, its efficacy was inferior to brimonidine. Further studies should explore optimal dosing, formulations, and long-term safety to clarify its prophylactic potential.