• What is most desirable first up: tube or trab?

• This question was attempted to be answered between 1999 and 2004, in multiple centres in the United States of America

• Patients enrolled were with the following criteria:

  • Aged 18 to 85: no paediatric patients

  • Patients had undergone either:

    • Previous trabeculectomy

    • Cataract surgery

    • Both

  • The pressure control was inadequate, with intra-ocular tension between 18 and 40mmHg, 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

• Re-operation rates higher in the trab group:

  • 9% in the tube group

  • 29% in the trab group

• Failure rates, significantly higher in the trab group:

  • 33% in the tube group

  • 50% in the trab group

• Kaplan Meier survival analysis revealed the cumulative probability of failure at five-years:

  • Tube = 29.8%

  • Trab = 46.9%

• 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

• BUT caution in interpretation:

  • Non-virgin eyes, with all eyes having an intervention prior to randomisation

  • 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

• This study has not been formally published, rather has been presented at the American Academy (originally October 2016)

• Patients with virgin eyes, with no previous ocular surgery, were randomised to either:

  • 117 eyes had tube

  • 108 had trab

• The majority of patients has primary open angle glaucoma, with a mean MD of -14

• The mean IOP at baseline was 23mmHg, on mean triple therapy

• At one year, the following results were observed:

  • 8% of the trab group had failed

  • 20% of the tube group had failed

  • 59% of the trab group had complete success

  • 14% of the tube group had complete success

• My interpretation of this paper:

  • Still a trabeculectomy is gold standard and primary choice for advanced open angle glaucoma

• Assessed the efficacy, safety and cost-effectiveness of clear lens extraction versus YAG iridotomy as the first line management paradigm.

• The study was an International multi-center trial with contributions from Australia (1), China (1), Hong Kong (2), Malaysia (2), Singapore (2) and the UK (22).

• The inclusion criteria included:

  • Phakic patients, over the age of 50 years

  • PACG, with IOP greater than 30mmHg

• The exclusion criteria were:

  • Advanced GON

  • Symptomatic cataract

  • AACG, with emergency with intervention

• Computer randomisation to two of treatment:

  • PI (208 eyes) versus lens extraction (211 eyes)

    • 18% of the latter group, alos had goniosynechiolysis

  • If both eyes were eligible, the eye with the most severe disease was recruited

• Summary of results:

• Economic analyses only done in the UK centres, revealed that lens extraction was initially more expensive:

  • PI (£1486)

  • Lens extraction (£2467)

•  Significant ETDRS loss of more than 10 letters:

  • One eye in the lens extraction group

  • Three eyes in the PI group

• Further requirement of surgical intervention:

  • One eye in the lens extraction group

  • 24 eyes in the PI group

• Twelve eyes in the PI arm eventually went on to have lens extraction ultimately, within the 60-day timeframe of the study.

• My interpretation of this study:

  • In the right patient subgroup of PAC, clear lens extraction is the right evidence based approach. Careful consent it the key.

• A fenestrated microstent, with a curvature that follows the contour of the sclera into the supracilliary space. Hence it increases the aqueous outflow from the AC to the supra-choroidal space, via the uveo-scleral pathway

• This multi-centred, interventional randomised control trial from 24 sites in the United States of America evaluated the two-year safety and efficacy of supra-cilliary micro-stents for treating patients with mild-moderate open angle glaucoma (with untreated pressures of 21-33mmHg) at the same time as cataract extraction.

• 505 subjects randomised to:

  • 131 phaco only

  • 374 phaco + CYPASS

• Baseline IOP in the two groups:

  • Phaco only = 24.5±3.0,

  • Phaco and CyPass = 24.4±2.8

• At 24 months, the IOP reduction from baseline:

  • Phaco only = 5.4mmHg

  • Phaco and CyPass = 7.4mmHg

• The mean medication requirement reduction at 24 months:

  • Phaco only = from 1.4±0.9 to 0.2±0.6

  • Phaco and CYPASS = from 1.3±1.0 to 0.6±0.8

• My interpretation of this study:

  • Patients with mild to moderate glaucoma and an open angle undergoing cataract surgery can be considered for concurrent supra-choroidal shunts

• This study assessed the safety and efficacy of phaco-ECP

• A retrospective case review of 58 patients, including all aetiologies of glaucoma, with a single intervention of phaco + ECP

• Mean pre-surgical IOP was 21.54mmHg

• At 18 months and 24 months, the mean IOP reduced to 14.43 and 14.44mmHg respectively

• There was statistical significance in reduction of IOP at all time points

• This paper did not assess the role of cataract surgery alone

• Interpretation of the paper:

  • ECP is a useful adjunct at the time of cataract surgery to manipulate the inflow of pressure

  • If pressures of less than 14 are targeted, it will not be the treatment of choice: hence it does not replace trabeculectomy

  • A comparison of phaco versus phaco/ECP would be very useful

  • Whilst as a fellow at the Western Eye, I was part of the team that looked at three year outcomes in three arms of:

    • Phaco alone

    • Phaco ECP

    • Phaco iStent

  • The results will hopefully be published shortly

• This study is an ongoing, phase 4 trial in patients with POAG receiving a Xen implant

• The results commonly quoted are from the interim analysis, up to January 2016

• No incidence of blebitis, endophthalmitis or hypotony noted, although subsequently a report from Lim et al (London) of an endophthalmitis related to an exposed Xen has been documented

• 215 patients entered the trial, with a mean pre-operative IOP of 21.4mmHg, on a mean 2.6 topical medications

• At twelve months following Xen implantation, analysing the results of 164 patients:

  • Mean IOP = 13.8mmHg

  • Mean topical treatment = 0.6 drops

  • Percentage of patients with IOP less than 16mmHg = 88

• Cumulative dataset for all Xen implants, reveal the following complications:

  • Hyphema = 3.8%

  • Secondary surgical procedure related = 3.3%

• My interpretation of this study:

  • Xen has an important role in the paradigm of open angle treatment

  • Either as a combined or a stand-alone surgical procedure, it should be considered in those patients on multiple drops without advanced glaucomatous optic neuropathy

The author Gurjeet Jutley acknowledges the contributions of:
Daniel Jackson ST3 Oxford Eye Hospital
Dhakshi Muhundhakumar, ST3 Moorfields Eye Hospital
Zuzana Sipkova, ST6 Oxford Eye Hospital