Risk Factors for Early Postoperative Intraocular Pressure Elevation after Phacoemulsification in Trabeculectomized Eyes

ABSTRACT

PURPOSE: In this study, we investigated the frequency and risk factors for early postoperative intraocular pressure (IOP) elevation after phacoemulsification in patients with a prior trabeculectomy. METHODS: We performed a retrospective chart review of 200 eyes (172 patients, study group) with filtering bleb after previous trabeculectomy and 207 eyes (144 patients, control group) without previous trabeculectomy, who underwent temporal clear corneal phacoemulsification with posterior chamber lens implantation. Twelve possible risk factors including age, gender, glaucoma type, interval from trabeculectomy to phacoemulsification, axial length, preoperative IOP, preoperative bleb morphology (height, vascularity), glaucoma medication, and concomitant intraoperative procedures (iris manipulation, anterior vitrectomy, subconjunctival mitomycin C injection) were analyzed to identify independent risk factors using a multivariate logistic regression method. Early postoperative IOP elevation was defined as IOP value > or = 25 mm Hg or an IOP increase > or = 10 mm Hg the morning after surgery compared to the preoperative IOP. RESULTS: There was a significant difference in the frequency of IOP elevation between the study group (25 eyes, 12.5%) and control group (6 eyes, 2.9%; p < 0.001). The mean early postoperative IOP (15.2 +/- 6.7 mm Hg) was significantly higher than preoperative IOP (12.5 +/- 4.4 mm Hg) in the study group (p < 0.001). Risk factors for early postoperative IOP elevation were low bleb height (odds ratio; OR = 9.995, p = 0.003) and iris manipulation (OR = 4.831, p = 0.026) in the study group while risk factors were preoperative use of glaucoma medication (OR = 3.492, p = 0.004) and iris manipulation (OR = 34.249, p = 0.009) in the control group. CONCLUSIONS: Phacoemulsification increases the risk of IOP spike in prior trabeculectomized eyes, especially those with low bleb height and intraoperative iris manipulation. We suggest intraoperative and postoperative efforts to minimize intraocular inflammation and earlier follow-up examination in these patients.