4 Research recommendations
The Guideline Development Group has made the following recommendations for research, based on its review of evidence, to improve NICE guidance and patient care in the future.
The answer to this question is key to the recommendations on chronic disease monitoring intervals in this guideline. There is currently no identifiable evidence from randomised controlled trials (RCTs) in this area. Once diagnosed, people with COAG face lifelong treatment and monitoring. Monitoring based on risk-guided intervals would allow people who have a high risk of progression to sight loss to have more intensive monitoring and would stop people with slowly progressing disease having to attend unnecessary appointments. It would also focus resources on the people at greatest risk, making early detection of progression more likely and allowing damage to vision over time to be minimised. A randomised comparative trial of three perceived risk strata for progression to blindness randomised to different monitoring intervals is suggested. The outcome would be the progression events detected.
What are the current NHS national benchmarks for surgical success and complications in people with COAG undergoing trabeculectomy drainage surgery with and without pharmacological augmentation?
The answer to this question would provide more accurate and up-to-date evidence for surgical treatment in COAG. Surgical success and complication rates could then be used to update benchmarks for clinical audit and assist in planning service provision. It would also then be possible to inform people having surgery of the chances of success and complications. The current evidence base is the National Survey of Trabeculectomy. However, this is now 10 years old and techniques have changed. The benchmarks created from the new survey would set a standard against which newer techniques could be evaluated. The study design would be similar to the audit of 10 years ago, to allow comparison of outcomes now in the light of changes in technique and the recommendations made by that audit.
What is the clinical effectiveness and cost effectiveness of initial argon, diode or selective laser trabeculoplasty compared with prostaglandin analogues alone or laser trabeculoplasty plus prostaglandin analogues in combination in people with COAG?
The answer to this question would provide data on the comparative clinical effectiveness and cost effectiveness of laser treatment versus modern ocular hypotensive agents, particularly prostaglandin analogues. Laser treatment may control IOP in some people for a time without the need for topical medications, and in others it may offer additional benefit to topical medications. In either case there may be cost savings and improved prevention of progression. Existing trials of laser trabeculoplasty compared with pharmacological treatment use outdated pharmacological agents. Because of the lack of evidence, the role of laser trabeculoplasty in COAG management cannot be clearly defined. An RCT should be used to answer this research question, and sham laser treatment would be needed to enable double masking or at least single masking.
In people identified on primary examination as exhibiting possible COAG, OHT or suspected COAG, what is the comparative effectiveness of diagnosis by different healthcare professions?
Why this is important
The answer to this question has the potential to improve access to care by increasing the number of available healthcare professionals and locations. The current available evidence is weak. There is one RCT, but it is of limited general use because of its design. There has not been any large-scale research on service provision in this area in the past 10 years. However, the Department of Health did pilot alternative COAG care pathways, which shows that central government is interested in this area. Primary research and several RCTs would be needed to answer the questions in this research recommendation.
What is the clinical effectiveness and cost effectiveness of providing people with COAG with a 'glaucoma card' or individual record of care compared with standard treatment?
The answer to this question would provide evidence of better care in terms of treatment outcome and the experience that people with COAG have. Involving them and helping them understand how to manage their COAG could reduce stress and uncertainty and potentially improve adherence to medical treatment, allowing them to remain sighted for longer. No RCTs or systematic reviews on the subject were identified. The study design for the proposed research should be an RCT. A qualitative research component would be needed to develop an appropriate intervention and patient-focused outcome measure to assess the experience of people with COAG. A standard visual function (field of vision) test would be appropriate for evaluating visual outcome. A large sample size and long study period – probably at least 5 years – would be needed to determine visual outcome, with the associated cost implications.