AIM: To observe the intraocular pressure(IOP)control and bleb function after phacoemulsification in patients with previous history of successful/qualified success mitomycin-C augmented trabeculectomy.

METHODS: This was a retrospective cohort study. Data of patients who had undergone trabeculectomy between 1^st January 2013 to 31^st Dec 2015 with subsequent cataract surgery were extracted from server. All patients had previous either success/qualified success trabeculectomy done. They went through uncomplicated phacoemulsification via clear corneal incision. Postoperative follow-up, review of bleb and IOP readings using Goldmann tonometer were taken. Details that were investigated include postoperative IOP control, visual improvement, number of anti-glaucoma medications, as well as the timing from trabeculectomy to phacoemulsification. Comparison with control group was made.

RESULTS: Fifteen eyes from thirteen patients fulfilled the criteria for study and had undergone uncomplicated phacoemulsification on a post-trabeculectomy eye. Two of the eyes had secondary glaucoma while the other thirteen had primary glaucoma. All phacoemulsifications were done at least 6mo after trabeculectomy(mean 14.7±4.3mo). There was only 1 eye(6.7%)requiring anti-glaucoma medications before the cataract surgery. This number increased to 4(26.7%)at 1-year post-phacoemulsification. The number further increased to eight(53.3%)at 2y post-phacoemulsification. The number of anti-glaucoma drops needed after surgery at 2y ranged from 2-4. In all the 15 eyes, there was no statistically significant change in IOP control between pre-cataract surgery(mean 13.4±2.9 mmHg)compared to 1y(mean 14.1±3.2 mmHg, P=0.357)and 2y(mean 15.1±3.3 mmHg, P=0.212)post-phacoemulsification. Visual improvement after phacoemulsification however is significant, from a preoperative average visual acuity of LogMAR 1.52±1.00 to a postoperative average visual acuity of 0.53±0.54(P=0.000, paired t-test).

CONCLUSION: This analysis shows significant visual improvement following cataract surgery in post-trabeculectomy patients without compromising IOP control. However, a reduced bleb function is noted following the surgery evidenced by the increase in number of anti-glaucoma drops used after surgery especially two years after the cataract surgery. Patients should be counselled regarding the possibility of restarting on anti-glaucoma medications post-phacoemulsification. The timing and sequence of cataract and glaucoma surgery should be optimized for best outcome.