Deterioration of filtering bleb morphology and function after phacoemulsification

BACKGROUND: Trabeculectomy remains the most efficient method of lowering he IOP applied for the treatment of glaucoma refractory to pharmacological treatment. Cataract is concerned as the most frequent late complication of trabeculectomy. The aim of the study was to analyse the effect of phacoemulsification with posterior chamber lens implantation on the morphology and function of filtering bleb in patients after previous successful trabeculectomy. METHODS: The retrospective study included 122 eyes treated for primary open angle glaucoma, 50 eyes (study group) in which, after a successful trabeculectomy with5-Fluorouracil, phacoemulsification with posterior chamber lens implantation was performed, and 72 eyes (control group), in which only a successful trabeculectomy was conducted. The surgical success of the trabeculectomy was expressed as IOP < 17 mmHg. RESULTS: In the group of patients subjected to both trabeculectomy and phacoemulsification, mean IOP was significantly higher than in the group of patients who underwent trabeculectomy after 6 months (p = 0.003), 12 months (p = 0.01) and 18 months (p = 0.007) of observation. The filtering blebs after phacoemulsification in the study group were characterized by a greater reduction, compared to those in the control group. Cox regression survival success was 75% (SE = 5.9; 95% CI: 63.4 – 86.6), 75% (SE = 5.9; 95% CI: 63.4 – 86.6), 71% (SE = 5.4; 95% CI: 60.4 – 81.6) in study group and 92% (SE = 1.8; 95% CI: 91.5 – 98.5), 92% (SE = 1.9; 95% CI: 88.3 – 95.7), 91% (SE = 2.0; 95% CI: 87.1 – 94.9) in control group after 6, 12 and 18 months, respectively. CONCLUSIONS: Phacoemulsification causes a significant elevation of IOP in the eyes after previous successful trabeculectomy and deterioration of filtering bleb morphology.