Could One Extra Injection Make Glaucoma Surgery Last Longer? New Evidence Points to Better Trabeculectomy Success

This audio article is from VisualFieldTest.com.Read the full article here: https://visualfieldtest.com/en/could-one-extra-injection-make-glaucoma-surgery-last-longer-new-evidence-points-to-better-trabeculectomy-successTest your visual field online: https://visualfieldtest.comSupport the show so new episodes keep coming: https://www.buzzsprout.com/2563091/supportExcerpt:Could One Extra Injection Make Glaucoma Surgery Last Longer? New Evidence Points to Better Trabeculectomy Success Evidence reviewed through August 30, 2026 Introduction Trabeculectomy remains one of the most powerful operations for lowering eye pressure in advanced or progressing glaucoma. It can reduce eye pressure to levels that are difficult to achieve with eye drops, laser treatment, or many newer minimally invasive procedures. Its main weakness is scarring. After surgery, the body may treat the new drainage pathway as an injury that needs to be repaired. Fibroblasts move into the area, collagen is deposited, and the filtering bleb can become thick, flat, or sealed. When that happens, the operation may gradually lose its effect. A new long-term report suggests that a single intravitreal injection of bevacizumab given during trabeculectomy, in addition to mitomycin C, may substantially improve the chance that the operation remains medication-free three years later. The reported difference is striking: 92.3% medication-free success with bevacizumab plus mitomycin C 71.2% medication-free success with mitomycin C alone Absolute difference: approximately 21 percentage points Approximate number needed to treat: 5 patients The result is important, but it is not yet enough to conclude that every patient undergoing trabeculectomy should receive the injection. The trial was relatively small, took place at one center, involved a largely European-ancestry population, and has not yet been independently reproduced with the same technique. The Short Answer The new evidence is promising and biologically plausible, and it is stronger than most earlier studies of anti–vascular endothelial growth factor treatment during trabeculectomy. However, the evidence currently supports the following conclusion: > Intravitreal bevacizumab may be a useful adjunct to mitomycin C in selected trabeculectomy patients, but it is not yet established routine care. The apparent benefit seems to come mainly from better control of the early postoperative wound-healing response, rather than from permanently lowering eye pressure by itself. The injection produced larger, less inflamed blebs early after surgery, and this early advantage was associated with fewer medications and fewer failures later. The next step should be larger, independent, multicenter trials with more diverse patients and at least five years of follow-up. What the New Randomized Trial Actually Found Study design and patient population The study was the three-year follow-up of the Bevacizumab in Trabeculectomy Study, conducted at a single tertiary ophthalmic center in South Australia. It included adults with progressing glaucoma for which the treating surgeon believed trabeculectomy was necessary. Participants could undergo: Primary trabeculectomy Redo trabeculectomy Trabeculectomy combined with cataract surgery A total of 131 patients were randomized: 65 patients received bevacizumab 66 patients received placebo The bevacizumab group received 1.25 milligrams in 0.05 milliliters by intravitreal injection at the end of trabeculectomy. The control group received an intravitreal injection of balanced salt solution. Both groups also received trabeculectomy with mitomycin C. The surgical protocol used: Mitomycin C concentration of 0.04% Two minutes of exposure for lower-risk eyes Three minutes for higher-risk eyes A standardized fornix-based surgical technique A standardized scleral flap and suturing approach The original trial was double-masked, randomized, and placebo-controlled. Both the patient and surgical team were masked to whether bevacizumab or placebo had been injected. The randomization was stratified by surgeon and by primary versus redo trabeculectomy in the original trial. Intravitreal Bevacizumab Improves Trabeculectomy Survival at 3 Years () There were some important population details: The average age was approximately 76 years. About 91% of eyes underwent primary rather than redo trabeculectomy. Nearly all participants were of European ancestry: 129 of 131 participants in the original report. Combined cataract surgery was more common in the bevacizumab group: approximately 34% compared with 18% in the control group. Active retinal vascular disease, active iris neovascularization, and several unusual forms of glaucoma were excluded. The cataract-surgery imbalance is important. Combined cataract surgery can sometimes reduce trabeculectomy success, although the investigators found that it did not independently explain the results. How did the researchers define success? The study used a personalized target eye pressure, based on the patient’s preoperative eye pressure and visual-field damage. This is more individualized than simply defining success as an eye pressure below 21 millimeters of mercury. Complete success Complete success meant that: Eye pressure remained at or below the patient’s target No topical pressure-lowering medication was needed This is the basis for the widely reported 92% versus 71% medication-free success result. Qualified success Qualified success meant that: Eye pressure remained at or below the target Additional eye drops were allowed if needed Failure Failure occurred if: Eye pressure was above the target on at least two occasions despite maximum medical treatment Further glaucoma filtration surgery was required Irreversible blindness resulted from glaucoma or a surgical complication A return to the operating room to treat early hypotony-related maculopathy was not automatically classified as surgical failure because it is a recognized complication of filtration surgery. Intravitreal Bevacizumab Improves Trabeculectomy Survival at 3 Years () Three-year results At 36 months, the reported survival estimates were: For the full table, please open this article on visualfieldtest.com. The statistical results were: Complete success: P = .001 Hazard ratio for complete-success failure: 0.17, 95% confidence interval 0.06 to 0.52, P = .002 Qualified success: P = .03 Hazard ratio for qualified-success failure: 0.07, 95% confidence interval 0.01 to 0.80, P = .03 A hazard ratio of 0.17 suggests that the bevacizumab group experienced approximately 83% fewer failures over the follow-up period, although hazard ratios should not be interpreted as exactly the same as an 83% reduction in individual patient risk. Absolute risk reduction and number needed to treat Using the reported three-year success percentages: Complete success Failure with bevacizumab: approximately 7.7% Failure with mitomycin C alone: approximately 28.8% Absolute reduction in failure: approximately 21.1 percentage points Approximate number needed to treat: 5 In practical terms, if the result applies to similar patients, treating about five patients with the additional intravitreal injection could result in one additional patient remaining medication-free at three years. Qualified success Failure with bevacizumab: approximately 1.5% Failure with mitomycin C alone: approximately 10.6% Absolute reduction in failure: approximately 9.1 percentage points Approximate number needed to treat: 11 These numbers are approximate because the study used survival analysis with some loss to follow-up, rather than a simple comparison in which every patient was observed continuously for exactly three years. Did bevacizumab permanently lower eye pressure? Not clearly. The bevacizumab group had lower eye pressure at approximately one month, but later average eye pressures were similar. This does not mean the treatment had no effect. The control group required more rescue treatment, including: Additional eye drops Bleb needling with 5-fluorouracil Further glaucoma surgery Once these rescue treatments were given, the average eye pressures in the two groups became more similar. Therefore, the more meaningful result may be that bevacizumab helped the original operation work without additional treatment. Did it reduce repeat glaucoma surgery? The 12-month report found that approximately: 2% of patients in the bevacizumab group required further glaucoma surgery 10% of control patients required further glaucoma surgery That is an approximate absolute reduction of 8 percentage points, corresponding to a rough number needed to treat of 13 to avoid one additional glaucoma operation during the first year. However, the three-year publication primarily reported survival outcomes rather than a detailed, independently powered comparison of repeat operations. It would be inappropriate to assume that the same eight-percentage-point reduction continues unchanged to five years. Intravitreal Bevacizumab Improves Trabeculectomy Survival at 12 Months () What Happened to the Bleb? The study included detailed photographic assessments using the Moorfields Bleb Grading System. At one month, blebs in the bevacizumab group were: Larger in central area Larger in total area Taller Less inflamed around the blood vessels The reduction in vessel inflammation was statistically very strong, with P values below .0001 in several comparisons. By later visits, many of these differences had become smaller or disappeared. Bleb height remained greater in the bevacizuSupport the show