Identification and critical appraisal of evidence for interventions for refractive error to support the development of the WHO package of eye care interventions: a systematic review of clinical practice guidelines.

Authors: Evans JR, Lawrenson JG, Ramke J, Virgili G, Gordon I, Lingham G, Yasmin S, Keel S.

Geographical coverage: Canada, the United Kingdom and the USA

Sector: Treatment

Sub-sector: Guidelines, interventions

Equity focus: None specified

Study population: Global

Review type: Other review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background: The World Health Organization is developing a Package of Eye Care Interventions (PECI) to support the integration of eye health care into national health programmes. Interventions included in the PECI should be based on robust evidence where available. Refractive error is a leading cause of blindness and vision impairment and is a PECI priority condition.

Objectives: The aim of this study was to provide high-quality evidence to support the development of the PECI by identifying and critically appraising clinical practice guidelines (CPGs), and extracting recommendations for refractive error interventions.

Main findings:

The authors reviewed 12 guidelines from six organizations in three countries. These guidelines were divided into two categories: assessment (eight guidelines) and treatment (four guidelines). Assessment guidelines included vision screening (five guidelines) and comprehensive medical eye evaluations (three guidelines), targeting both children and adults. Treatment guidelines covered optical, pharmacological, laser, and surgical treatments for refractive error.

The guidelines were developed by organizations in Canada, the UK, and the USA. Guidelines recommend some form of eye examination for infants, pre-school children, school-aged children and adults. There were differences, however, in the specified type, targeted population and frequency of that examination.

In regards to vision screening, authors found the following recommendations: vision screening at least once in all children aged 3-5 years inclusive to detect amblyopia or its risk factors (high certainty), vision screening recommended before the age of 3 years is mixed (weak certainty) and recommendations on vision screening in people aged 65 years and above (low certainty).

In relation to interventions, authors found that specific recommendations on use of spectacles and contact lenses were rare but were implicit in all the guidelines. Authors noted LASEK, PRK and LASIK interventions to be equally effective in correcting myopia, however, authors note careful attention to adverse effects. Evidence for laser correction of surgically inducted refractive error following non-refractive ophthalmic surgery was found to be adequate, however, short-term safety was only available for refractive error induced after insertion of an intraocular lens. Authors noted that corneal inlay for correction of presbyopia was not recommended. Interventions to slow progression of myopia recommended include the use of antimuscarinic agents (atropine) and orthokeratology, and limiting the time spent outdoors.

Authors conclude there is consensus from high-quality clinical practice guidelines that children between the ages 3 and 5 years, inclusive, should have some form of eye evaluation. However, there were differences as to whether this should be vision screening to detect children at risk or a comprehensive eye examination. Recommendations for vision screening/examination at other ages varied. Furthermore, authors note the lack of guidelines focused on low and middle income countries.


Inclusion criteria of studies were as follows: 1) those that defined clinical guidelines using the institute of medicine definition; 2i) people with refractive error, including myopia, astigmatism, presbyopia and anisometropia; 3) all interventions for refractive error, including interventions related to the identification of refractive error, for example, vision screening; 4) published from 2010 onwards; 5) no commercial funding and no unmanaged conflicts of interest; affiliations of all authors available; 6) information available on the strength of the recommendations; and 7) with average quality score of 3 for items 4, 7, 12, 22 and the overall average score for each of nine items of 4, 7, 8, 10, 12, 13, 15, 22, 23 was 45 or more. There were no restrictions on the population considered: all ages and all locations. Searches were restricted to the last 10 years (published from 2010 onwards) and written in English.

Authors searched bibliographic databases, guideline databases and professional society websites for clinical practice guidelines (CPGs). The searches were conducted initially in March 2019 and repeated in March 2020. A top-up search of the guideline databases in October 2021 did not identify any further updated guidelines relevant to this topic.

Study screening for inclusion in the review was conducted by two reviewers independently and conflicts were resolved by discussion. Two authors assessed the quality of included studies using the Appraisal Guidelines for research and Evaluation II (AGREE II). Criteria developed by the WHO Package of Rehabilitation Interventions were used to assess whether the CPG was of sufficient quality. Authors used a pre-piloted standardised form for data extraction and collected standardised information on the guidelines.


Applicability/external validity:

The authors focused on guidelines from high-income countries. They defined ‘screening’ as identifying individuals at higher risk, not providing a definitive diagnosis. Eye examinations in healthy individuals could also be considered screening. There is a high consensus that children aged 3-5 should have an eye examination, but recommendations for other ages vary. The authors caution that these recommendations may not be generalizable as they are based on guidelines from high-income countries.

Geographic focus: The clinical guidelines identified recommendations were largely drawn from these settings, often where a large proportion of the population have access to good quality eye care services. Authors note the extent to which these recommendations apply to settings where high-quality eye health care is less accessible, and the prevalence of correctable vision impairment is higher, is unclear.

Summary of quality assessment:

This study used appropriate methods to analyse the recommendations of clinical practical guidelines, to appraise the quality of the guidelines. Furthermore, authors acknowledged limitations of this review and do not generalise guideline recommendations. Therefore, a medium confidence was attributed in the conclusions about the effects of this study.

Publication Source:

Evans JR, Lawrenson JG, Ramke J, Virgili G, Gordon I, Lingham G, Yasmin S, Keel S. Identification and critical appraisal of evidence for interventions for refractive error to support the development of the WHO package of eye care interventions: a systematic review of clinical practice guidelines. Ophthalmic Physiol Opt. 2022 May;42(3):526-533.