«Glaucoma Diagnosis and management of chronic open angle glaucoma and ocular hypertension METHODS, EVIDENCE & GUIDANCE APRIL 2009 Commissioned by the ...»
National Collaborating Centre
for Acute Care
Diagnosis and management of chronic open angle
glaucoma and ocular hypertension
METHODS, EVIDENCE & GUIDANCE
Commissioned by the National Institute
for Health and Clinical Excellence
Diagnosis and management of
chronic open angle glaucoma and ocular hypertension
METHODS, EVIDENCE & GUIDANCE
The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore for general use.
The rights of National Collaborating Centre for Acute Care to be identified as Author of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act, 1988.
ISBN 0-9549760-6-1 Front cover image: © Irina Tischenko. BigStockPhoto.com 3
FOREWARDForeword “O loss of sight, of thee I most complain!” John Milton (1608–1674) The World Health Organisation has estimated that globally there are 12.5 million people blind from glaucoma with the total number affected by this condition around 66 million.
Approximately 10% of UK blindness registrations are ascribed to glaucoma and around 2% of people older than 40 years have chronic open angle glaucoma, a figure which rises to almost 10% in people older than 75 years. With changes in population demographics the number of individuals affected by glaucoma is expected to rise. Based on these estimates there are around 480,000 people affected by chronic open angle glaucoma in England, who receive over a million glaucoma related outpatient visits in the hospital eye service annually.
Once diagnosed, affected individuals require lifelong monitoring for disease control and to detection of possible progression of visual damage. Once lost, vision cannot be restored, disease control with prevention, or at least minimisation of ongoing damage is therefore paramount to maintenance of a sighted lifetime.
Chronic open angle glaucoma, and its frequent precursor, ocular hypertension are the subject of this NICE guideline. Individuals with early to moderate chronic glaucoma are mostly asymptomatic and unaware of any damage to their field of vision. Once vision loss becomes apparent up to 90% of optic nerve fibres may have been irrecoverably damaged. Early detection and effective treatment by healthcare professionals are thus key elements in avoiding permanent blindness. Screening and case finding have been the subject of a published HTA assessment and lie outside the scope of this guidance, which focuses on prevention of vision loss through treatment.
Reports on treatments for chronic open angle glaucoma (COAG) have been systematically searched out and evaluated. The clinical effectiveness, cost effectiveness and patients’ views of a variety of treatments have been professionally assessed by the scientists and methodologists in the National Collaborating Centre for Acute Care (NCC-AC), with interpretation and setting in context by the clinicians and patient representatives comprising the Guideline Development Group (GDG). Long term lowering of intraocular pressure (IOP) remains the only strategy known to be effective against sight loss. As a long term progressive condition, COAG presents challenges to the researcher in terms of the extended time frames necessary to assess comparative outcomes of direct relevance to vision. Many shorter duration randomised treatment trials focus on IOP reduction and for this reason a link was sought between pressure reduction and protection against vision loss. Methodologically crucial, this link formalises the use of IOP reduction as a valid proxy or surrogate outcome and quantifies IOP reduction in terms of protection of vision. A further methodological achievement lay in establishing a quantitative relationship between visual loss and reduced quality of life, without which economic evaluation of the evidence would have been problematic.
4 GLAUCOMA Ocular hypertension (OHT) is elevated eye pressure in the absence of visual field loss or glaucomatous optic nerve damage. It is estimated that 3% to 5% of those over 40 years have OHT, around one million people in England. OHT represents a major risk for future development of COAG with visual damage. Lowering IOP has been shown to protect against conversion to COAG. A key question for the guideline therefore related to whether or not treatment for OHT would be cost effective in preventing vision loss in the long term. Once again, establishment of a quantitative link between IOP reduction and protection against development of COAG and the threat to a sighted lifetime was an essential step in the assessment of the cost effectiveness of treating OHT. Without a detailed knowledge of the cost effectiveness of treatment for various risk strata of OHT, recommendations for preventative treatment would not have been possible.
The main treatments covered in the guideline are pharmacological agents for topical use as eye drops, laser procedures and drainage surgery with or without pharmacological augmentation. Where multiple randomised controlled trials (RCT) of sufficient quality were found these were merged using meta-analytical techniques in order to obtain a single result from all available evidence. Reporting of adverse events and patients’ views from trials and other sources was considered and factored into the interpretation of evidence by the GDG.
Evaluation of the cost effectiveness of the various treatment options for both COAG and OHT required the development of original cost effectiveness analyses carried out by the NCC-AC staff. For the clinicians and patient representatives of the GDG this important aspect of the guideline was relatively unfamiliar territory at the outset. The professional staff of the centre however provided general and specific guidance which allowed the GDG to not only understand these complex analyses, but also to influence them with clinically relevant information. Thus drainage surgery may appear to be the most cost effective treatment when analysed, but this result needs to be interpreted in the context of relatively rare though serious complications, as well as patient preference, fear of surgery and personal risk aversiveness.
Despite meticulous methodology and attention to detail there will always remain areas of uncertainty. Trial evidence may be absent, and where this exists it cannot refer to those patients whose clinical features lie outside the inclusion criteria and extrapolations are required when stepping beyond the fringes. Even within the boundaries of the evidence there are uncertainties, hence the clinically familiar use of confidence intervals around effect sizes.
Dealing with uncertainty in the economic evaluation requires a different approach, a sensitivity analysis varies the model’s input parameters and examines the impact this has on the model outputs. Science and medicine aside, the circumstances and views of individual patients must be taken into account and ‘one size’ will never ‘fit all’. Thus there will always be clinical exceptions and the intention of the guideline is to provide recommendations which will apply to 80% of clinical situations on 80% of occasions.
Management of a largely asymptomatic though potentially irreversibly blinding long term condition such as COAG requires ongoing monitoring by healthcare professionals.
Measurement of intra ocular pressure is a convenient device for assessing level of disease control but the ultimate outcome is preservation of vision. Rates of progression vary widely between patients and timely detection of progression requires accurate and consistent measurement of visual fields with assessment of optic nerve head features over years.
Conscientious and regular monitoring according to the perceived threat to a patient’s sighted lifetime is crucial to success and the quality of any service has much to do with this aspect of patient care. Unusually in this NICE guideline we were asked to include recommendations on the most appropriate service models. To this end we considered options for management of different patient groups in terms of relevant healthcare professionals, their roles, their 5 FOREWARD training requirements, and the standards of performance which might be expected of them.
We also considered requirements for equipment and issues of continuity of care for patients.
There have been many challenges and methodological obstacles encountered in the development of this clinical guideline. Overcoming these stands is a testament to the effort, commitment and quality of the professionals in the collaborating centre, and the dedication and expert knowledge of the clinician members and patient representatives of the guideline development group. Our efforts will be amply rewarded if this guideline helps to preserve vision for those whose sighted lifetime is threatened by that ‘silent thief of sight’, chronic open angle glaucoma.
GUIDELINE DEVELOPMENT GROUP MEMBERSHIP AND ACKNOWLEDGMENTS
GLOSSARY OF TERMS
1.1 WHAT IS A GUIDELINE?
1.2 THE NEED FOR THIS GUIDELINE
1.3 THE NATIONAL COLLABORATING CENTRE FOR ACUTE CARE
1.5 WHAT THE GUIDELINE COVERS
1.6 WHAT THE GUIDELINE DOES NOT COVER
1.7 WHO DEVELOPED THIS GUIDELINE?
1.8 ASSUMPTIONS MADE
2.1 GUIDELINE METHODOLOGY
2.2 DEVELOPING THE CLINICAL QUESTIONS
2.4 LITERATURE SEARCH
2.5 HIERARCHY OF CLINICAL EVIDENCE
2.6 LITERATURE REVIEWING PROCESS
2.7 METHODS OF COMBINING STUDIES
2.8 DEVELOPMENT OF THE RECOMMENDATIONS
2.9 RESEARCH RECOMMENDATIONS
2.10 PRIORITISATION OF RECOMMENDATIONS FOR IMPLEMENTATION
2.11 VALIDATION OF THE GUIDELINE
2.12 RELATED NICE GUIDANCE
2.13 UPDATING THE GUIDELINE
3 SUMMARY OF RECOMMENDATIONS
3.1 KEY PRIORITIES FOR IMPLEMENTATIONS
3.2 COMPLETE LIST OF RECOMMENDATIONS
3.4 RESEARCH RECOMMENDATIONS
4.. DIAGNOSIS OF PATIENTS WITH OCULAR HYPERTENSION, CHRONIC OPEN ANGLE GLAUCOMA AND SUSPECTED CHRONIC OPEN ANGLEGLAUCOMA
5 MONITORING OF PATIENTS WITH OCULAR HYPERTENSION, CHRONIC OPEN ANGLE GLAUCOMA AND SUSPECTED CHRONIC OPENANGLE GLAUCOMA
5.2 INTRAOCULAR PRESSURE MEASUREMENT (IOP)
5.3 ANTERIOR CHAMBER ANGLE MEASUREMENT
5.4 VISUAL FIELD MEASUREMENT
5.5 OPTIC NERVE ASSESSMENT
5.6 MONITORING INTERVALS FOR PATIENTS WITH OHT AND COAG SUSPECTS
5.7 MONITORING INTERVALS FOR PATIENTS WITH COAG
5.8 SUMMARY OF RECOMMENDATIONS ON MONITORING OF PATIENTS WITH OHT, COAG OR SUSPECTED COAG106
5.9 RESEARCH RECOMMENDATION ON MONITORING PATIENTS WITH OHT, COAG AND SUSPECTED COAG...1096 OVERVIEW OF TREATMENT
6.2 ANY TREATMENT VS. NO TREATMENT
7 TREATMENT OF OCULAR HYPERTENSION AND SUSPECTED CHRONIC OPEN ANGLE GLAUCOMA
7.2 MATRIX OF TREATMENTS CONSIDERED IN OUR CLINICAL QUESTIONS
7.3 PHARMACOLOGICAL TREATMENT FOR OHT AND SUSPECTED COAG
7.4 ADVERSE EVENTS ASSOCIATED WITH PHARMACOLOGICAL TREATMENTS
7.5 THE RISK OF CONVERSION FROM OCULAR HYPERTENSION TO CHRONIC OPEN-ANGLE GLAUCOMA..............152 7.6 RECOMMENDATIONS AND LINK TO EVIDENCE
7.7 SUPPORTING RECOMMENDATIONS
7.8 SUMMARY OF ALL RECOMMENDATIONS ON TREATMENT FOR PATIENTS WITH OHT AND SUSPECTED COAG157 8 TREATMENT OF CHRONIC OPEN ANGLE GLAUCOMA
8.2 MATRIX OF TREATMENTS CONSIDERED IN OUR CLINICAL QUESTIONS
8.3 PHARMACOLOGICAL TREATMENT FOR COAG
8.4 ADVERSE EVENTS ASSOCIATED WITH PHARMACOLOGICAL TREATMENTS
8.5 LASER TREATMENT FOR COAG
8.6 SURGICAL TREATMENT FOR COAG
8.7 PATIENTS WITH COAG OR OHT ASSOCIATED WITH PSEUDOEXFOLIATION OR PIGMENT DISPERSION.........210 8.8 RECOMMENDATIONS AND LINK TO EVIDENCE
8.9 SUPPORTING RECOMMENDATIONS
8.10 SUMMARY OF ALL RECOMMENDATIONS ON TREATMENT FOR PATIENTS WITH COAG
8.11 RESEARCH RECOMMENDATIONS ON TREATMENT FOR PATIENTS WITH COAG
9 COMPLEMENTARY AND ALTERNATIVE INTERVENTIONS
9.2 COMPLEMENTARY AND ALTERNATIVE TREATMENTS
10 SERVICE PROVISION
10.2 MATRICES OF HEALTHCARE PROFESSIONALS CONSIDERED IN OUR CLINICAL QUESTIONS
10.3 EFFECTIVENESS OF DIAGNOSIS BY DIFFERENT HEALTHCARE PROFESSIONALS
10.4 EFFECTIVENESS OF MONITORING BY DIFFERENT HEALTHCARE PROFESSIONALS
10.5 EFFECTIVENESS OF TREATMENT BY DIFFERENT HEALTHCARE PROFESSIONALS
10.6 SUMMARY OF ALL RECOMMENDATIONS ON SERVICE PROVISION
10.7 RESEARCH RECOMMENDATION ON SERVICE PROVISION
11PROVISION OF INFORMATION FOR PATIENTS
11.2 SUMMARY OF RECOMMENDATIONS ON PROVISION OF INFORMATION FOR PATIENTS
11.3 RESEARCH RECOMMENDATION ON PROVISION OF INFORMATION FOR PATIENTS
8 GLAUCOMA BIBLIOGRAPHY