Faq's
- BUT caution in interpretation:
- Non-virgin eyes, with all eyes having an intervention prior to randomization
- MMC was administered for 4 minutes, which is not done in clinical practice
- Only Baerveldt 350 tubes were used: whilst I use this in Oxford, surgeons throughout the world use different shunt devices
- Clinically, hypotonous eyes with good vision are not considered a failure: converse to the study design
- My interpretation of this paper:
- Patients with failed trabeculectomy should undergo tube surgery
- Can give patients general figures of per annum 10% failure risk of trabs compared to 5% in the tube group
- Kaplan Meier survival analysis revealed the cumulative probability of failure at five-years:
- Tube = 29.8%
- Trab = 46.9%
- Failure rates, significantly higher in the trab group:
- 33% in the tube group
- 50% in the trab group
- Re-operation rates higher in the trab group:
- 9% in the tube group/li>
- 29% in the trab group
- Re-operation rates higher in the trab group:
- 9% in the tube group
- 29% in the trab group
- What is most desirable first up: tube or trab?When the tube versus trabeculectomy (TVT) study reported its initial findings a decade ago, we learned that tube shunt surgery provided comparable reductions in mean intraocular pressure (IOP) to trabeculectomy but higher success rates than trabeculectomy and fewer complications. Long-term follow-up of the TVT cohort confirmed these findings through 5 years of postoperative observation. These findings came as the popularity of tube shunt surgery was already climbing and the number of trabeculectomy surgeries was falling. It seemed a paradigm shift was in the making, in which tubes could be the preferred first-line surgery for glaucoma, replacing trabeculectomy.
- Patients enrolled were with the following criteria:Aged 18 to 85: no paediatric patients
- Patients had undergone either:
- Previous trabeculectomy
- Cataract surgery
- The pressure control was inadequate, with intra-ocular tension between 18 and 40 mmHg, on tolerated medical treatment
- 212 eyes of 212 patients were recruited and allocated to the following groups:
- 107 = Tubes
- 107= Trabs
- Failures defined as:
- IOP more than 21mmHg or less than 5mmHg
- Patients requiring a secondary operation (including trans-scleral diode)
- The pressure not reduced less than 20% below baseline on two consecutive visits after three months
- The five-year data was published in 2012, revealing that at this interval:
- Mean IOP reduction from baseline in the tube group = 10.2mmHg
- Mean IOP reduction from baseline in the trab group = 12.4mmHg
- No statistical significance after three months
- The mean number of drops reduction from baseline:
- 1.8 in the tube group
- 1.7 in the trab group