Evaluation of subconjunctival bleb function after trabeculectomy with mitomycin c using ultrasound biomicroscopy

Purpose: To investigate the relationship between filtering bleb function and ultrasound biomicroscopic (UBM) images.Materials and Methods: The study analyzed UBM parameters, including intrableb reflectivity, maximum height of the subconjunctival filtering bleb, the route under the scleral flap, and the presence of intrableb microcysts, in correlation to surgical outcomes.The trabeculectomy blebs were accepted clinically successful when the post-operative IOP was 21 mmHg without antiglaucoma medications.Results: A total of 63 eyes of 52 patients were included in the study.The median time between trabeculectomy and the UBM examination was 41 mo (range, 2-188 mo).The surgery was completely successful in 23 eyes, partially successful in 31 eyes, failed in 9 eyes.The presence of cysts inside the bleb was correlated significantly with complete success (p=0.007).The completely visible route under the scleral flap was significantly frequent in cases of complete and partially successful cases than functional failure cases (p<0.001).The median maximal height of the filtering bleb was significantly higher in cases of complete success (1.4,0.8-3.0m) than partial success (0.9, 0.5-2.2m) and failed (0.7, 0.4-1.4m) subgroup (p<0.001).The high-reflectivity filtering bleb was significantly frequent in cases of functional failure than other groups (p<0.001).Conclusion: Ultrasound biomicroscopy is an useful imaging modality for the functional evaluation of the bleb after trabeculectomy.The presence of visible route under the scleral flap, intrableb cysts, low reflectivity and high bleb height in UBM increase the success of trabeculectomy surgery.