Purpose: To evaluate the magnitude and pattern of intraocular pressure (IOP) changes in the contralateral eye following unilateral glaucoma surgery, with a focus on comparing fluctuations between glaucomatous and non-glaucomatous fellow eyes. Methods: In this prospective study, 197 patients with primary and secondary glaucoma, who underwent glaucoma surgery in one eye were included. IOP measurements in both operated and fellow eyes were recorded preoperatively and postoperatively at specified intervals. Patients treated with oral acetazolamide preoperatively were analysed separately. A postoperative IOP change of ± 4 mmHg or 20% change from the baseline value in the fellow unoperated eye was considered clinically significant. The primary outcome was change in mean IOP in the fellow eye, while clinical escalation was evaluated as a secondary outcome. Results: The mean baseline IOP and mean number of glaucoma medications in the operated eye were 18.6 ± 7.4 mmHg and 2.5 ± 1.1 and in the fellow eye, it was 16.1 ± 4.2 mm Hg and 1.9 ± 1.2. Most patients (45.7%) were diagnosed with primary open-angle glaucoma (POAG). Out of 197 fellow eyes, 17 (8.62%) eyes were normal and not on any glaucoma medications. No statistically significant postoperative IOP change was observed in fellow eyes across all time points. However, clinical escalation was observed in our study participants, 33% of fellow eyes required additional glaucoma medications, and 9.75% required glaucoma surgery within 6 months. Conclusion: Although unilateral glaucoma surgery did not produce a statistically significant change in IOP in the contralateral eye, a sizeable proportion of fellow glaucomatous eyes required clinical escalation, including surgery. Vigilant monitoring of fellow eye IOP and therapeutic needs is therefore essential.
Karunanithi et al. (Wed,) studied this question.