Abstract
Purpose: :
To evaluate the long-term tonometric outcomes of repeat versus initial trabeculectomy with adjunctive mitomycin C (MMC) and to compare their efficacy in achieving a range of intraocular pressures (IOP) in patients with open-angle glaucoma (OAG).
Methods: :
This is a retrospective cohort study of sixty-seven patients (75 eyes) with OAG who underwent repeat trabeculectomy with MMC and sixty-four patients (75 eyes) with OAG who underwent initial trabeculectomy with MMC. Success was defined by the following criteria: (A) IOP ≤ 21 mmHg and a reduction of IOP ≥ 15% from baseline, (B) IOP ≤ 18 mmHg and a reduction of IOP ≥ 20% from baseline, (C) IOP ≤ 15 mmHg and a reduction of IOP ≥ 25% from baseline, and (D) IOP ≤ 12 mmHg and a reduction of IOP ≥ 30% from baseline. Kaplan-Meier survival analyses were used to assess outcomes. Cox's proportional hazard regression analyses were used to identify risk factors for failure. The primary outcome was qualified success rate according to the defined criteria. The secondary outcomes included IOP, number of medications, visual acuity, complications, and the need for further surgery.
Results: :
For criterion A, the difference in success rate between initial and repeat trabeculectomy was of borderline significance at five years (46% and 32%, respectively, P = 0.085). For criteria B, C, and D, the cumulative probabilities of success over five years were significantly different between the initial and repeat trabeculectomy groups: 46% and 27% (criterion B, P = 0.031), 38% and 22% (criterion C, P = 0.008), and 28% and 12% (criterion D, P = 0.004), respectively. Prior cataract surgery was associated with a decreased risk for failure in repeat trabeculectomy for criteria A and B (relative risk 0.34 and 0.36, P = 0.021 and 0.025, respectively).
Conclusions: :
Repeat trabeculectomy with MMC is less successful at achieving more robust intraocular pressure reduction than is initial trabeculectomy with MMC after five years. Prior cataract surgery is associated with a statistically significant decreased rate of failure for repeat trabeculectomy.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • clinical (human) or epidemiologic studies: risk factor assessment