Surgical outcomes of trabeculectomy in eyes with low to lownormal baseline intraocular pressure.

Abstract

Purpose : To determine surgical outcomes of trabeculectomy for patients with low preoperative intraocular pressure.

Methods : The retrospective cohort study included patients requiring trabeculectomy(TB) with mitomycin C with preoperative intraocular pressures(IOP) less than 15mmHg from March2006 to May2017. Patients with at least 1 year follow-up in the post-operative period were included. Demographic and clinical data were collected at the preoperative visit and post-operative visits for up to 7 years. Surgical failures were defined as eyes that required reoperation or progressed to no light perception.

Results : Forty eyes of 31 patients met inclusion criteria. Mean patient age was 75.2±9.3 years old and mean follow-up duration was 61.2±23.0 months(range: 14-93). 6(15%) eyes experienced surgical complications:2(5%) bleb leak,4(10%) scarred/encapsulated trabeculectomy blebs. 4 eyes developed IOP less than 6mmHg; however, none developed hypotony related complications.10(25%) eyes were documented to have failed TB with a mean duration of 29.5±28.2 months prior to failure. All failure(100%) were due to the need for reoperation secondary to inadequate IOP control: 8(20%) tube shunt, 2(5%) repeat TB,1(2.5%) CyPass microstent.1(2.5%) eye required 2 reoperations including a repeat TB followed by CyPass microstent. Mean IOP between preoperative and each post-operative visit was not significantly different, which was 12.7±2.7 preoperatively and ranged from 11.4±3.3 to 12.2±4.3 mmHg postoperatively for up to 5 years(p>0.05 for all). Humphrey 24-2 visual field(VF) mean deviations(n=11) were not significantly different at -12.9±7.2 and -12.9±8.2(p=1) during the most recent preoperative and postoperative visits, respectively. 24-2 mean slopes were significantly different at -1.3±1.8 and 1.4±3.8(p=0.012) during the preoperative and postoperative periods, respectively. Octopus 30-2 VF mean defects(n=9) were not significantly different at 11.1±7.1 and 12.6±9.9(p=0.385) at the most recent preoperative and postoperative visits, respectively. 30-2 mean slopes were not different at 1.4±2.0 and 0.45±2.1(p=0.445) during the preoperative and postoperative periods, respectively.

Conclusions : Although the IOP was not significantly lower than low-normal preoperative IOP, there was no significant progression on VF. Mean deviation/defect remained stable and 24-2 mean slope even showed possible slowing of glaucomatous VF progression.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.