Is Beta Radiation Better than 5 Flurouracil as an Adjunct for Trabeculectomy Surgery When Combined with Cataract Surgery? A Randomised Controlled Trial

Abstract

IntroductionIn an African setting surgery is generally accepted as the treatment of first choice for glaucoma. A problem with trabeculectomy surgery for the glaucomas is the frequent co-existence and exacerbation of cataract. We report a randomized controlled trial to compare the use of beta radiation with 5FU in combined cataract and glaucoma surgery.Participants and MethodsConsenting adults aged >40 years with glaucoma, an IOP>21mmHG and cataract were enrolled and randomised to receive either 1000cG β radiation application or sub-conjunctival 5fluorouracil (5FU) at the time of combined trabeculectomy and phaco-emulsification with lens implant surgery.Results385 individuals were eligible for inclusion of whom 301 consented to inclusion in the study (one eye per patient). 150 were randomised to the 5FU arm and 151 received β radiation. In the 12 months following surgery there were 40 failures (IOP>21mmHg) in the 5FU arm and 34 failures in the beta arm. The hazard ratio for the beta radiation arm compared to the 5FU arm, adjusted for IOP at baseline, was 0.83 (95% c.i. 0.54 to 1.28; P = 0.40). The improvement from mean presenting visual acuities of 0.91 and 0.86 logMAR to 0.62 and 0.54 in the 5FU and beta arms respectively was comparable between groups (P = 0.4 adjusting for baseline VA). Incidence of complications did not differ between the two groups.DiscussionThis study highlights several important issues in the quest for a therapeutic strategy for the glaucomas in an African context. Firstly, there is no evidence of an important difference between the use of 5FU and beta radiation as an anti-metabolite in phacotrabeculectomy. Secondly phacotrabeculectomy is a successful operation that improves visual acuity as well as controlling IOP in a majority of patients. Although the success of trabeculectomy in lowering IOP is reduced when combined with phacoemulsification compared with trabeculectomy alone, this finding has to be set against the possible need for subsequent cataract surgery following trabeculectomy alone, which represents a second trip and expense for the patient and results in 10–61% failure of the trabeculectomy at one year post-cataract surgery.Trial RegistrationISRCTN Registry ISRCTN36436933

Reporting Harm in Glaucoma Surgical Trials: Systematic Review and a Consensus-Derived New Classification System

“…In reporting the severity of adverse events, two large multicenter trials defined sight threatening complications as loss of at least 2 lines of Snellen VA or return to the operating room. 1,2,3,26,27,28 Five studies provided definitions of major, devastating or severe complications in their methodology 1,2,3,26,27,28,34,45,48 or attempted to give examples of them 16,17 . The different descriptions of severe or major complications are detailed in Table 2.…”

Phacoemulsification compared with phacotrabeculectomy surgery: a within-person observational cohort study

“…Details of the PTT are published elsewhere 12. In summary, patients with primary open angle glaucoma and cataract fulfilling the inclusion criteria (table 2) were recruited in the PTT.…”

“…Each enrolled patient underwent PT on the eye with better VA with random allocation to receive either adjunctive 5FU or beta radiation at the time of surgery 12. In a number of patients enrolled in the trial, phacoemulsification with intraocular lens (IOL) implant alone was subsequently performed in the fellow eye.…”

The control of conjunctival fibrosis as a paradigm for the prevention of ocular fibrosis-related blindness. “Fibrosis has many friends”

“…However, the β-radiation group had a higher risk of cataract [32], but this may have been associated with lower pressures which is less often seen with newer GFS such as the Moorfields Safer surgery System [6]. When β-radiation was compared with intraoperative 5-FU, there was no difference in risk of failure or complication following phacotrabeculectomy [33]. More recently, randomised trials have shown that β-radiation with MMC are superior to MMC alone [34].…”