Post-Trabeculectomy Hypotony: Clinical Outcomes and Effect on Post-Operative Antiglaucoma Medication Use

INTRODUCTION: The aim of this study was to evaluate the clinical outcomes of post-trabeculectomy hypotony and the effect of hypotony on the final number of glaucoma medications used.
METHODS: Data pertaining to 34 patients (34 eyes) who developed hypotony after trabeculectomy were analyzed retrospectively and compared with the data of 35 patients (35 eyes) without hypotony after trabeculectomy. We compared pre-operative, intraoperative, and post-operative data between the groups and evaluated hypotony recovery time and the effects of hypotony on visual acuity, final intraocular pressure (IOP), and number of glaucoma medications used.
RESULTS: The mean follow-up times were 30±18 and 29±18 months in the hypotony and control groups, respectively. There were no significant differences in pre-operative or intraoperative data between the groups (p>0.05). IOP values at post-operative 1 day, 1 week, 1 month, and 3 months were lower in the hypotony group compared to the control group (p<0.05), while 6-month and final IOP values were similar (p>0.05). Hypotony resolved at a mean of 4±2 (1–11) weeks. There was no difference between the groups in terms of post-operative vision loss (p>0.05). The number of glaucoma medications used postoperatively was lower in the hypotony group (p=0.009) and was significantly reduced in both groups compared to preoperatively (p<0.001). The decrease in the number of glaucoma medications used was higher in the hypotony group (p<0.05). At the last follow-up, 11.8% of patients in the hypotony group and 42.9% of the control group used glaucoma medication (p<0.001).
DISCUSSION AND CONCLUSION: According to our study, post-operative 6 month and final IOP levels were similar in eyes with and without post-trabeculectomy hypotony. Hypotony resolved within 1 month on average and had no significant effect on future vision loss. Patients with hypotony were less likely to need glaucoma medication postoperatively and used fewer glaucoma medications than patients without hypotony.