Short-Term IOP Lowering Effect on the Contralateral Eye After 180° Selective Laser Trabeculoplasty.

PURPOSE: To assess the contralateral intraocular pressure (IOP) lowering effect following 180° selective laser trabeculoplasty (SLT) in the untreated eye and to compare IOP reduction between treated and untreated eyes. METHODS: This prospective, interventional, non-randomized study included 40 treated eyes and 40 fellow eyes with open-angle glaucoma, and insufficient IOP control. Preoperative and postoperative IOP were measured using a Goldmann applanation tonometer. Subjects were treated with 50 non-overlapping laser pulses over 180° of the angle. IOP was measured bilaterally before SLT and at 1 week, 1 month, 3 months, and 6 months thereafter. RESULTS: IOP changes were assessed in both the treated and contralateral eyes, revealing a significant reduction throughout the six-month follow-up. In the treated eye, IOP decreased from 20.23 ± 4.74 mmHg pre-SLT to 15.58 ± 3.13 mmHg (p < .001), while the contralateral eye decreased from 18.28 ± 3.87 mmHg to 15.88 ± 3.89 mmHg (p = .004) at the last follow-up visit. The treated eye consistently showed a greater percentage reduction, with contralateral effects of 65.47%, 68.14%, 60.32%, and 58.64% at 1 week, 1 month, 3 months, and 6 months, respectively. A strong positive correlation was found between IOP reduction in the contralateral eye and the corresponding treated eye (r = 0.718, p < .001), and a moderate correlation with the treated eye's baseline IOP (r = 0.368, p = .020). CONCLUSION: A statistically significant contralateral IOP reduction was observed following 180° SLT.