Effectiveness of trabeculectomy with mitomycin C for glaucomatous eyes with low intraocular pressure on treatment eye drops

Abstract

Purpose: To examine the efficacy and safety of current trabeculectomy with mitomycin C in Japan for glaucomatous eyes with low intraocular pressure (IOP). Methods: Two hundred ninety-four eyes of 294 patients with IOP ≤21 mmHg before surgery were studied; all patients were participants in the Collaborative Bleb-related Infection Incidence and Treatment Study (CBIITS), a multicentre, prospective, cohort study conducted at 34 ophthalmological institutions throughout Japan. All eyes had an intraocular pressure ≤ 21 mmHg and had undergone trabeculectomy alone or phacotrabeculectomy. Two success criteria were used: Criterion A comprised 20% reduction of baseline IOP and Criterion B comprised 30% reduction of baseline IOP. The primary outcome was the success rate for each of these criteria. Results: The qualified success rates were 87.3% for Criterion A and 42.0% for Criterion B at 5 years. Mean IOP was significantly reduced, from 16.7 AE 2.7 to 11.6 AE 4.0 mmHg at 5 years after trabeculectomy (p < 0.0001); the number of anti-glaucoma medications significantly decreased from 2.7 AE 1.1 to 1.0 AE 1.2 (p < 0.0001) at 5 years after the surgery. Three or more trabeculectomies, and needling were related to increased risk of failure. Incidences of postoperative hyphema, infection, shallow anterior chamber and bleb leakage were 2.4%, 2.4%, 2.0% and 3.4%, respectively. Conclusions: This study showed that trabeculectomy with mitomycin C is an effective procedure with few surgical complications for reducing IOP in patients, even if preoperative IOP was within the normal range.

Reply

“…Needling procedures were performed at the investigator's discretion, and it is not surprising that all were done in the trabeculectomy group. The needling rate of 20% in the PTVT Study does not seem excessively low and is higher than reported in the TVT Study 2 and large cases series of trabeculectomy with mitomycin C. 3,4 Additional needling procedures may be required during the final 2 years of the PTVT Study to prevent surgical failure. TO THE EDITOR: Failure and success criteria according to intraocular pressure measurements are often used in glaucoma trials 1 to analyze the longevity and comparative success of surgical interventions.…”

“…This is in contrast with a more typical situation where there is a greater effect size as the sensitivity of the outcome increases. 4 Generally speaking, qualified success criteria are harder to interpret owing to the added variable of medication introduction and response. Clinicians could be introducing medications at different IOP levels based on preconceived notions of management for the unmasked intervention, or different interventions may have different IOP responses to medications.…”

Ab interno goniotomy with a Kahook Dual Blade in 6-month follow-up

“…An increased risk is observed not only for intraoperative but also postoperative complications related to the filtration bleb, including infectious and metabolite-associated complications, or the development of malignant glaucoma. There is also an elevated risk of hypotony and related complications such as maculopathy, choroidal detachment or the development of cataract in phakic eyes [50]. With drainage implants there is a risk of complications related to the implant itself.…”

Success and Failure Factors for Trabeculectomy in Glaucomatous Patients in Southwest China: A 325 Eyes Analysis

“…Studies have shown that IOP is not the speci c factor responsible for glaucomatous optic nerve damage, but rather some circulating and metabolic factors. We presume that visual function may be maintained when the IOP is controlled at the target level by surgery or topical medications [30].…”