The Effect of Trabeculectomy on the Intraocular Pressure of the Unoperated Fellow Eye

PURPOSETo investigate the intraocular pressure (IOP) changes in the unoperated fellow eye in patients who underwent trabeculectomy. MATERIALS AND METHODSIOP changes in the unoperated fellow eyes of 107 patients who underwent trabeculectomy in 1 eye for high-tension glaucoma (48 primary open-angle glaucoma, 43 pseudoexfoliative glaucoma, and 16 narrow-angle glaucoma) were evaluated during the early postoperative period. All IOP measurements were recorded during the postoperative first 3 months and compared with preoperative values. RESULTSMean preoperative IOP levels were 37.0 ± 10.0 mm Hg in the operated eyes and 15.1 ± 3.1 mm Hg in the fellow eyes. Mean IOPs in the unoperated eyes on the postoperative first-day, first- and second-week, and first- and third-month visits (17.1 ± 5.7, 17.5 ± 5.1, 18.5 ± 5.4, 18.6 ± 5.1, and 19.0 ± 5.9 mm Hg, respectively) were significantly different compared with the preoperative levels for each period of time (P < 0.01). Eight fellow eyes underwent operations for uncontrolled glaucoma before month 3. Among the remaining 99 eyes, higher postoperative IOP values were measured in 33 (33%) eyes at all postoperative visits compared with the preoperative IOP levels. A consistent IOP rise equal to or higher than 5 mm Hg was detected in 12 eyes (12%) and a consistent IOP elevation of 30% or more was found in 14 eyes (14%) during the postoperative first 3 months. Contralateral IOP elevation was not correlated with patient age, type of glaucoma, or preoperative antiglaucomatous medications prescribed to the operated or fellow eyes. CONCLUSIONAfter filtration surgery, IOP of the unoperated fellow eye should also be monitored closely in order not to overlook a possible insidious rise, especially in glaucomatous eyes that were previously under good medical control.