Systematic review and appraisal of quality, definitions and treatment recommendations of clinical guidelines for glaucoma suspects

To appraise the quality of clinical practice guidelines for glaucoma suspects, and to assess their consistency for how a ‘glaucoma suspect’ is defined and their recommendations for treatment initiation for such individuals.

Glaucoma is an optic neuropathy characterised by progressive degeneration of retinal ganglion cells (RGCs), characteristic changes in optic nerve and neuroretinal tissue structure, and associated visual sensitivity deficits.Despite progress in our understanding of its underlying pathophysiology and advances in diagnosis and treatment over the past three decades, glaucoma remains one of the leading causes of irreversible visual impairment and blindness globally. 1Early detection of glaucoma is therefore important, particularly for those at a higher lifetime risk of vision loss and blindness, so that such individuals can be appropriately managed to minimise the risk of developing such irreversible vision loss.
A definitive clinical diagnosis of glaucoma-especially in the early stages of the disease-remains challenging, and conventionally relies on clinical assessment of the optic nerve and visual field testing.However, there is often only moderate inter-observer agreement in the assessment of optic nerve for the presence of glaucoma, 2 and visual field tests often exhibit large degrees of measurement variability. 3][18] High-quality clinical practice guidelines that provide evidence-based guidance on the management of glaucoma suspects might therefore be expected to contribute to minimising the global impact of glaucoma.][21] The present study sought to systematically identify and critically appraise the quality of international clinical practice guidelines relating to the clinical care of glaucoma suspects.This study also sought to assess the relative consistency of guidance across these guidelines, including aspects such as how a 'glaucoma suspect' is defined, and what recommendation(s) are made for the initiation of treatment of such individuals.An understanding of these factors is essential to identify gaps in practice recommendations, including potential inconsistencies in approaches across geographic regions, and to identify areas where evidence-based clinical care of glaucoma suspects may be limited by insufficient high-quality evidence.

| METHODS
This study critically appraised the quality of clinical practice guidelines for glaucoma suspects, which was defined in this study as any document that self-identified as a 'guideline' and that provided recommendations for the clinical care of glaucoma suspects (including diagnosis and management).The clinical practice guidelines were identified through a systematic review, which has been reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. 22The protocol was prospectively published on PROSPERO (CRD42020206978). 23

| Search strategy
Comprehensive searches (with details provided in the Supplementary Materials) were performed in OVID Medline and EMBASE, based on the presence of the keywords 'glaucoma' and 'guideline' appearing in the abstract, title or keywords.Searches were also performed in Google Scholar based on the keywords of 'glaucoma' and 'guideline' or 'guidelines' in the title.Finally, searches were performed in Guideline Central Summaries (https://www.guidelinecentral.com/summaries/),Turning Research into Practice (TRIP) database (https://www.tripdatabase.com/), and the Canadian Agency for Drugs and Technologies in Health (https://www.cadth.ca)using the keyword 'glaucoma'.The searches were limited to a date range from 1 January 2010 and 25 May 2022 (the latter being the date that the searches were performed).

| Selection of clinical practice guidelines
Citations from the searches were imported into EndNote and duplicates were removed.The remaining references were uploaded into Covidence (Veritas Health Innovation Ltd; Melbourne, Australia; https://www.covidence.org) to undergo a two-stage process for selection of relevant clinical practice guidelines.In the first stage, two of the review authors (L.E.D. and Z.W.) independently screened titles and abstracts.Full text documents were obtained for any reference deemed to be at least potentially relevant by at least one of the review authors.The two review authors then independently examined each full text to determine its suitability for inclusion.This study only included documents that were written in English, and documents that self-identified as a 'guideline' and provided recommendations for any aspect of the clinical care of glaucoma suspects.Any discrepancies in assessment were resolved by discussion between the two review authors; reasons for exclusion at this stage were documented.

| Data extraction and presentation
For each included clinical practice guideline, two review authors (S.K. and Z.W.) independently extracted: (1) key general characteristics, including the organisation, year of publication, country, target audience, and funding source; (2) the definition of a 'glaucoma suspect', and whether the guideline specifically defined a 'primary open angle glaucoma (POAG) suspect' and/or a 'primary angle closure (PAC) suspect'; (3) recommendations for treatment initiation, and whether the recommendation was formal (i.e., from a clearly identifiable section or list with specific description[s] or statement [s] regarding what action is appropriate for a particular situation or population), whether the quality of the evidence for the recommended was assessed, and whether a statement about the strength of the recommendation is provided.Any discrepancies in the data extracted were resolved by discussion between the two review authors and the senior review author (L.E.D.).
A table was used to present the key characteristics of the guidelines, and another table was used to present whether an individual with a specific characteristic (e.g., having a family history of glaucoma, or suspicious visual field test results) would meet the definition of a glaucoma suspect based on the definition of each guideline, and the distinction between a glaucoma, POAG and/or PAC suspect.Two additional tables were used to summarise the recommendations for initiating treatments for POAG and PAC suspects separately, along with the characteristics of these recommendations.

| Quality appraisal of clinical practice guidelines
The quality of each clinical practice guideline was independently critically appraised by two review authors (S.K. and Z.W.) using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument (https://www.agreetrust.org/),which assesses methodological quality based on 23 items across the following six domains 24 : 1. Scope and purpose: 'is concerned with the overall aim of the guideline, the specific health questions, and the target population' (3 items) 2. Stakeholder involvement: 'focuses on the extent to which the guideline was developed by the appropriate stakeholders and represents the views of its intended users' (3 items) 3. Rigour of development: 'relates to the process used to gather and synthesise the evidence, the methods to formulate the recommendations, and to update them' (8 items) 4. Clarity of presentation: 'deals with the language, structure, and format of the guideline' (3 items) 5. Applicability: 'pertains to the likely barriers and facilitators to implementation, strategies to improve uptake, and resource implications of applying the guideline' (4 items) 6. Editorial independence: 'is concerned with the formulation of recommendations not being unduly biased with competing interests' (2 items) Each item was scored on a seven-point Likert rating scale based on the level of agreement with the statement for the item.For the AGREE II instrument, 24 a score of 1 corresponded to 'Strongly Disagree' and was given 'when there is no information that is relevant to the AGREE II item, if the concept is very poorly reported, or if the authors state explicitly that criteria were not met'.A score of 7 corresponded to 'Strongly Agree', which was given 'if the quality of reporting is exceptional and where the full criteria and considerations articulated in the User's Manual have been met'.Scores between 2 and 6 were 'assigned when the reporting of the AGREE II item does not meet the full criteria or considerations.A score is assigned depending on the completeness and quality of reporting.Scores increase as more criteria are met and considerations addressed'.The overall quality score for each domain was calculated by expressing the sum of the scores of all items in a domain as a percentage of its maximum possible score.As there is currently no well-established definition for what constitutes a domain with 'high' methodological quality, we used this term to describe domains with a score of >66% in this study.This value was chosen based on the following rationale: if a score of 1 ('Strongly Disagree') and 7 ('Strongly Agree') corresponds to a value of 0% and 100% respectively on a 7-point Likert scale, and a score of 4 represents the mid-point in the scale (and thus representing neither agreement nor disagreement with a statement, and would have a value of 50%), then a score of 5 would represent some degree of agreement with a statement and would have a value of 67%.Domains with an overall quality score of >66% would therefore reflect an average score of ≥5 on the 7-point Likert scale.

| Statistical analysis
The level of inter-rater agreement for the score of each item and domain from the AGREE II tool was evaluated using the intraclass correlation coefficient (ICC), by assessing the absolute agreement of individual ratings in a two-way random-effects model (as each clinical practice guideline was rated by the same set of two review authors, who are assumed to be randomly drawn from the population of raters).ICC values were interpreted as follows: <0.40 as 'poor', 0.40-0.59as 'fair', 0.60-0.74as 'good', and 0.75-1.00as 'excellent'. 25The level of agreement between features used to define a 'glaucoma suspect' or 'POAG suspect' for a subset of guidelines where a definition was provided was also determined using Cohen's kappa.These values were interpreted as follows: <0.00 as 'poor', 0.00-0.20 as 'slight', 0.21-0.40 as 'fair', 0.41-0.60 as 'moderate', 0.61-0.80 as 'substantial', and ≥0.81 as 'almost perfect'. 26Analyses were performed using Stata software (version 16, StataCorp; College Station, TX, USA).

| Search results
The database searches identified 1196 potentially relevant records and 2 records were manually included based on suggestions by experts in the field; 217 duplicates were removed and 889 were excluded following title and abstract screening.A further 72 records were excluded from the full-text review, resulting in 20 clinical practice guidelines in the final analysis.A PRISMA flowchart summarising the selection of eligible guidelines, and reasons that full-text records were excluded, is shown in Figure 1.

| General characteristics and quality of guidelines
Table 1 summarises the general characteristics of the 20 included clinical practice guidelines.The guidelines were derived from Argentina, 27 Australia, 28,29 Brazil, 30 Canada, 31,32 India, 33 Kenya, 34 Malaysia, 35 Scotland, 36 Spain, 37 Sweden, 38 United Kingdom [39][40][41] United States, [42][43][44] the Asia-Pacific region 45 and Europe, 46 and were published between 2010 and 2022.Four guidelines were funded by government organisations, 28,35,36,41 two by the authoring organisation, 42,43 one by industry, 45 and one by the European Glaucoma Society Foundation. 46[38][39][40]44 Eye and/or healthcare providers or clinicians (including ophthalmologists and optometrists) were explicitly stated as the target audience in all guidelines, except for one guideline where it was not clearly stated (but likely F I G U R E 1 Selection process for identifying clinical practice guidelines providing recommendations for clinical care of glaucoma suspects.Following the removal of duplicates, the remaining records underwent a two-stage selection process to identify relevant guidelines written in English.This was based on a review of the title and abstract of the records in the first stage, and a review of the full text documents in the second stage. relevant for eye care professionals, and especially optometrists). 31he methodological quality of each clinical practice guideline was assessed using the AGREE II appraisal tool.Overall, there was good inter-rater agreement across all guidelines for the individual appraisal items (intraclass correlation coefficient [ICC] = 0.67; 95% confidence interval [CI] = 0.62 to 0.72) and excellent inter-rater agreement for the domain scores (ICC = 0.88; 95% CI = 0.82 to 0.91).The average score from the two graders for each of the six domains for each guideline is presented in Table 2.The highest scoring domain across all guidelines was for 'Clarity of Presentation', with 14 guidelines achieving a score of >66%.The lowest scoring domains across all guidelines were for 'Applicability', 'Editorial Independence' and 'Stakeholder Involvement'; three or less guidelines achieved a score of >66% for each of these domains.Only the National Institute for Health  33,36,39,44 Five guidelines only provided a definition of a PAC suspect, with all specifically for PAC disease or glaucoma 30,37,40,43 except for one guideline. 32Among the other 11 guidelines, the most common clinical features considered to define either a 'glaucoma suspect' or a 'primary open angle glaucoma [POAG] suspect' (the latter being explicitly defined in five guidelines) 34,35,41,42,45,46 were the presence of a suspicious optic disc or nerve appearance (n = 11), elevated intraocular pressure (IOP; n = 8), or suspicious visual field results (n = 7).However, there was overall only fair agreement among these nine guidelines in the clinical features used to define a 'glaucoma suspect' or 'POAG suspect' (kappa = 0.31; 95% CI = À0.14 to 0.76).In contrast, all the guidelines that defined a 'primary angle closure [PAC] suspect' included iridotrabecular contact (ITC) as part of the definition (n = 11).

| Recommendations for treatment initiation
Table 4 summarises the recommendations for initiating treatment for 'glaucoma suspects' or 'POAG suspects' in each of the 16 guidelines, excluding the four specifically for PAC disease or established glaucoma. 30,37,40,43Three guidelines did not provide any such recommendations, 31,32,44 one guideline 36 indicated that this topic was covered by a 2009 NICE guideline, 47 and one guideline only provided recommendations for assessing such individuals during the COVID-19 pandemic. 33Of the remaining 11 guidelines, treatment recommendations were mostly formal (n = 6), and most assessed the quality of the evidence used to derive the recommendation (n = 6), but only a few stated the strength of the recommendation (n = 3).Three guidelines clearly stated that glaucoma suspects or POAG suspects meeting a specific set of criteria should be treated, 27,28,34 whilst three guidelines clearly specified that treatment should not be offered to this patient population (of which two related to POAG suspects that do not have elevated IOP, 35,41 and one stated that treatments should not be initiated by optometrists prior to a management plan being formulated by an ophthalmologist), 39 although one made an exception for individuals that 'are at risk of visual impairment within their lifetime'. 41The five remaining guidelines did not specifically state whether treatment(s) should be initiated, but instead suspect', or 'PAC suspect' respectively.[1] A glaucoma suspect also includes those with a disc haemorrhage or peripheral anterior synechiae; [2] A glaucoma suspect also includes those with asymmetric IOP, and are also classified separately as high-or low-risk glaucoma suspects; [3] Guideline provided conflicting definitions of a POAG suspect on Pages 2 and 33, and the definition on Page 2 was used; [4] A glaucoma suspect also includes those with 'biomicroscopic abnormalities'; [5] No definition provided for a glaucoma or POAG suspect; [6]   [4]  indicated that interventions may potentially be warranted or considered relative to the individual patient circumstances. 29,38,42,45,4638,41 In the nine relevant guidelines, treatment recommendations were predominantly formal (n = 6) and guided by an assessment of the quality of evidence (n = 6); less than half stated the strength of the recommendation (n = 4).
All guidelines either clearly stated that PAC suspects meeting a specific set of criteria should be treated (n = 5) or indicated that treatment could potentially be warranted or considered (n = 4).Factors that were indicated to be relevant to inform whether or not treatment should be initiated for PAC suspects included: level of access to regular ophthalmic care (n = 7), need for repeated dilated exams (n = 6), symptoms suggestive of prior acute angle closure (n = 4), a family history of glaucoma (n = 4), PAC in the fellow eye (n = 3), and the use of drugs that could provoke pupillary block (n = 3).

| DISCUSSION
In this systematic review, a total of 20 clinical practice guidelines that provided recommendations for the care of glaucoma suspects were identified and evaluated.Of these, 16 (80%) were deemed to have low to moderate methodological quality, indicating substantial room for improvement in the development and reporting of international practice guidance for glaucoma suspect care.There was poorer agreement in how a glaucoma or POAG suspect was defined, compared to a PAC suspect, and a greater level of variation in the recommendations for treatment initiation of POAG suspects than of PAC suspects.
0][21] Low scores in the areas of editorial independence and stakeholder involvement raise concerns about potential biases in the recommendations made in these guidelines, and an absence or under-representation of the patient voice in the formulation of the recommendations.Only the UK NICE guideline 41 was judged to be of high methodological quality in all six domains; this is unsurprising, as NICE guidelines are developed based on the criteria of quality as described in the AGREE II instrument.The present study identified considerable variability across the clinical guidelines for how a POAG suspect is defined.The two guidelines assessed to have the most domains with high methodological quality (i.e., the NICE 41 and MSO 35 ) were aligned in their definition of a POAG suspect, as an individual with optic nerve head or visual field changes suspicious or suggestive of glaucomatous damage.Both of these guidelines 35,41 specifically distinguished POAG suspects from individuals with ocular hypertension.42,45 With the exception of the Australian NHMRC guideline, published in 2010, 28 seven out of these eight guidelines were judged to have two or fewer domains with high methodological quality. 27,29,31,34,38,42,45Three out of these eight guidelines also considered individuals with a family history of glaucoma as a glaucoma or POAG suspect. 27,29,45The NICE 41 and MSO 35 guidelines were also consistent in their recommendation that POAG suspects should not be treated for gluacoma. 35,4145,46 All guidelines that provided a recommendation for the treatment of PAC suspects were also consistent in recommending that those meeting a specific criteria should either be treated, or that treatment should be considered. 28,30,34,35,37,40,43,45,46These criteria included factors such as poor access to ophthalmic care, need for repeated pupillary dilation, symptoms suggestive of prior acute angle closure, a family history of glaucoma, PAC in the fellow eye, and/or the use of drugs that could provoke pupillary block.
Greater heterogeneity in the definition and recommendation for treatment initiation of POAG suspects compared to PAC suspects potentially reflects the knowledge gaps that currently exist about the early detection of glaucoma, and prediction of its development.When considering how POAG suspects are defined across different guidelines, all of them fundamentally describe an individual who is at an increased risk of developing glaucoma, as definitively diagnosed clinically.][10][11][12][13] The robust characterisation of such risk is foundational to the criteria used to define a POAG suspect, and how they should be managed.However, the NICE guideline for glaucoma 41 concluded that there was insufficient rigorous evidence to recommend a prognostic tool to accurately identify individuals at an increased risk of developing glaucoma, based on a critical review of the quality of evidence.Robust primary research studies on the development and validation of new prognostic tools are thus needed.Such novel tools may include those that enable the earlier detection of glaucomatous damage, or tools that capture early RGC structural and/or functional changes, prior to irreversible cell death. 48imilar variability was observed in the treatment recommendations for POAG suspects, potentially reflecting differences in the methodological approaches, and rigour, across different guidelines.For example, the NICE guideline for glaucoma 41 undertook a comprehensive network meta-analysis to estimate the clinical effectiveness of treating individuals with either ocular hypertension and suspected POAG; this estimate was then used in a health economic model to determine the cost-effectiveness of treatments.Considering the totality of this evidence, the NICE guideline recommended that POAG suspects and those with ocular hypertension, who also have an IOP <24 mm Hg, should not be offered treatment, unless they are 'at risk of visual impairment within their lifetime'; this exception was provided 'to allow flexibility and leave the decision down to the diagnosing optometrist or ophthalmologist along with the individual, to determine whether the person being assessed is likely to experience visual loss within their lifetime'. 41An expert committee made this recommendation as they were 'not convinced that there is sufficient evidence to suggest that people with a baseline IOP of less than 24 mmHg… are at a significant risk of ever converting to [POAG] to justify treating' and 'did not want to make recommendations that have considerable cost impact based on insufficient evidence of risk and treatment benefit'. 41In contrast, the POAG Suspect guideline by the American Academy Ophthalmology (AAO), 42 for example, did not include a formal or clear recommendation for treatment initiation of POAG suspects, and instead stated that '[a] patient who demonstrates very high IOP in which optic nerve damage is likely to occur may require treatment'.The guideline also recommended that '[in] some cases, initiating IOP-lowering treatment to lower the risk of glaucomatous damage may be appropriate if the patient has additional risk factors for glaucoma', and that '[clinicians] may consider using a risk calculator to determine the risk of progressing from ocular hypertension to POAG'.The quality of the body of evidence used to guide these recommendations was not assessed.
Although two clinical guidelines recommended against routine treatment initiation for POAG suspects without elevated IOP, 35,41 with the NICE guideline clarifying that this was based on the absence of evidence to warrant recommendation of their treatment, 41 this should not be interpreted as 'evidence of absence'namely that there is evidence suggesting that treatment of these individuals is not warranted.Instead, this highlights the need for further high-quality primary research evidence to clarify which POAG suspects without elevated IOP warrant treatment, and to more clearly determine which individuals are 'at risk of visual impairment within their lifetime' 41 where such treatment is especially warranted.This is crucial as it has been reported that there is a similar prevalence of POAG suspects without elevated IOP and those with ocular hypertension under care. 17In addition, a similar proportion of eyes with suspected POAG have been found to develop visual field damage over time as eyes with ocular hypertension. 49ey strengths of the present study include the use of comprehensive searches and independent reviewers to identify the relevant clinical guidelines, the extraction of and critical appraisal of these guidelines by two independent reviewers, and the use of a robust and wellrecognised appraisal tool (AGREE II).Although we recognise a level of subjectivity to AGREE II assessments, there was excellent agreement in the domain scores between the raters.We also acknowledge that this study did not specifically exclude guidelines that only provided recommendations for care of glaucoma suspects during the COVID-19 pandemic, and the specific recommendations for treatment initiation during this period may be less relevant beyond the COVID-19 pandemic.However, these guidelines were not excluded as they can still potentially include information relevant to this review, such as how a 'glaucoma suspect' is defined, and it remains equally important to understand the quality of such guidelines.In this study, only one guideline 33 was identified as meeting this description, and it did not provide recommendations for treatment in glaucoma suspects.
In conclusion, the present study identified that the methodological quality of most current international clinical practice guidelines that provide recommendations for the care of glaucoma suspects is suboptimal.This finding should be considered when using these guidelines to inform the care of glaucoma suspects in clinical practice, especially decisions relating to which POAG suspects may warrant treatment initiation.There was substantial heterogeneity across the guidelines for how to define a POAG suspect, and the criteria for commencing glaucoma treatment in this population.Together, these findings highlight important gaps in the current evidence for how to accurately predict glaucoma development, and the effectiveness of treatments for individuals with optic nerve head and/or visual field changes suggestive of glaucomatous damage, but without elevated IOP.
Yes= presence of this characteristic would meet the definition of a glaucoma suspect by the guideline.Cells shaded blue, green, and yellow represent definitions specifically for a 'glaucoma suspect', 'POAG

Table 3
General characteristics of the clinical practice guidelines providing recommendations for clinical care of glaucoma suspects that were included.Quality of each clinical practice guidelines providing recommendations for clinical care of glaucoma suspects.presents a summary of how a 'glaucoma suspect' was defined in each guideline, based on whether particular clinical characteristics formed part of the definition.Four guidelines did not provide any definition for what constituted a glaucoma suspect.
36A B L E 1 and Care Excellence (NICE) guideline41had all six domain scores >66%.The Malaysian Society of Ophthalmology (MSO) guideline35had five domain scores >66%, and the National Health and Medical Research Council (NHMRC)28and Scottish Intercollegiate Guidelines Network (SIGN)36guidelines both had four domain scores >66%.The remaining 16 guidelines had only two or less domains with scores >66%.T A B L E 2 T A B L E 3 Clinical features used to define a 'glaucoma suspect' in each clinical practice guideline.
Guideline provided conflicting definitions of a POAG suspect on Pages 156 and 160, and the definition on Page 156 is presented herein, as the latter is ambiguous and defines a POAG suspect as one with 'clinical findings and/or a constellation of risk factors that indicate an increased likelihood of developing [POAG]'.Recommendations for treatment initiation of 'glaucoma suspects' or 'primary open angle glaucoma (POAG) suspects' in each clinical practice guideline.
Abbreviations: AAO, American Academy of Ophthalmology; EGS, European Glaucoma Society; IOP, intraocular pressure; ITC, iridotrabecular contact; NHMRC, National Health and Medical Research Council; NICE, National Institute for Health and Care Excellence; PAC, primary angle closure; PACG, PAC glaucoma; POAG, primary open angle glaucoma; PPG COVID-19 Pandemic, Preferred Practice Guideline During COVID-19 Pandemic; RANZCO, Royal Australian and New Zealand College of Ophthalmologists; RNFL, retinal nerve fibre layer; SIGN, Scottish Intercollegiate Guidelines Network.aSuch as pseudoexfoliation, pigment dispersion syndrome, and high myopia.WU ET AL.T A B L E 4 Note:[1]IOP >21 mm Hg, age >50 years, family history of glaucoma, or African descent;[2]Defined as those with a central corneal thickness (CCT) <555 μm, history of eye trauma, systemic illnesses (e.g., diabetes or autoimmune disease), or systemic medications at risk of provoking glaucoma;[3]Defined as 'fellow eye with established GON (excluding secondary unilateral glaucomas); [ocular hypertension] with multiple risk factors (thin CCT, high IOP, suspicious disc); GLC gene mutation associated with severe glaucoma; recurrent optic disc haemorrhages; PXF syndrome; younger age';[4]'Established risk factors for POAG, besides elevated IOP, include older age, family history of glaucoma, African-derived race or Latino/Hispanic ethnicity, thin central cornea, low ocular perfusion pressure, diabetes mellitus, myopia, low systolic and diastolic blood pressure, disc haemorrhage, large cup-to-disc ratio, high pattern standard deviation on threshold visual field testing, hypothyroidism, and male sex';[5]'[Treatment] is indicated for [glaucoma suspects] when the risks of progressive disease outweigh the risks and potential side effects of treatment' and that these individuals 'should be offered treatment based on estimated risk of conversion to POAG'.Abbreviations: AAO, American Academy of Ophthalmology; EGS, European Glaucoma Society; MoH Kenya, Ministry of Health, Republic of Kenya; NHMRC, National Health and Medical Research Council; NICE, National Institute for Health and Care Excellence; RANZCO GIG, Royal Australian and New Zealand College of Ophthalmologists Glaucoma Interest Group; SIGN, Scottish Intercollegiate Guidelines Network.Recommendations for treatment initiation of primary angle closure (PAC) suspects in each clinical practice guideline.: AAO, American Academy of Ophthalmology; EGS, European Glaucoma Society; NHMRC, National Health and Medical Research Council; RANZCO, Royal Australian and New Zealand College of Ophthalmologists; SIGN, Scottish Intercollegiate Guidelines Network.
a From a clearly identifiable section or list with specific description(s) or statement(s) regarding what action is appropriate for a particular situation or population.b Assessment of the quality of the evidence related to this recommendation.T A B L E 5 Abbreviationsa From a clearly identifiable section or list with specific description(s) or statement(s) regarding what action is appropriate for a particular situation or population.b Assessment of the quality of the evidence related to this recommendation.c Provision of a statement about the strength of the recommendation.