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NIHR Signal A patch or eye drops are similarly effective for the treatment of “lazy eye” in children

Published on 5 December 2019

doi: 10.3310/signal-000849

Both the use of a patch or atropine eye drops are equally suitable methods for improving clarity of vision (visual acuity) in children and young adults with amblyopia (a “lazy eye”).

Amblyopia is a cause of poor vision in childhood that usually affects only one eye, resulting in the individual relying more on the good eye. The standard methods of treatment involve training the weaker eye and promoting its use by covering the strong eye with a patch, or eye drops to blur the vision in the good eye.

This NIHR-funded systematic review evaluated seven trials comparing 1,177 children treated with one of the methods. The findings reinforce existing knowledge that both forms of treatment are similarly effective and that the choice of method is down to child and parental preferences.

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Why was this study needed?

Amblyopia is the commonest vision deficit in children, affecting about 2 in 100 children in the UK. It happens when the connection between the eye and the brain is impaired, but the eye itself is healthy.

Patching (occlusion), in which a patch is placed on the stronger eye for a number of hours, is the most common method of treatment. Another accepted method is the use of atropine eye drops (penalisation) which works by temporarily blurring eyesight in the better eye.

The researchers updated the previous version of this review, first published in 2009, using new evidence to compare the effectiveness and safety of patching compared with atropine drops for the treatment of a lazy eye.

What did this study do?

This systematic review included seven trials comparing patching with atropine drops in participants with a lazy eye, regardless of the severity of the condition. Only randomised controlled trials and quasi-randomised controlled trials were selected for inclusion.

The trials included 1,177 participants between 2 and 20 years of age. They were conducted in six countries, but no trials were from the UK. Four new trials were added to the original 2009 review. Treatment for at least two hours per day was given for 17 weeks to two years. 

Differences in starting vision between trials and varying treatments prevented meta-analysis and may affect the interpretation of the findings from this review, but the research was of adequate quality.

What did it find?

  • Evidence from six of the seven trials showed that both the patch and atropine drops produced an improvement in visual acuity in the weaker eye in the short-term (one to six months) and in the long-term (24 months). The magnitude of improvement varied between trials, and the results could not be pooled.

  • There was no meaningful difference between the two treatments in improving visual acuity or binocular function. 

  • Although use of the patch and the drops were generally well tolerated, the drops were associated with better adherence and quality of life.

  • Side effects included reduced visual acuity in the stronger eye, which was more common in those using atropine, but this did not require treatment in nearly all cases. Light sensitivity was also experienced after atropine drops. Eyelid irritation was more common when using a patch.

What does current guidance say on this issue?

The 2016 NICE Clinical Knowledge Summary on the topic of squints in children also covers the treatment of lazy eye.

It suggests that both occlusion and penalisation are options but also mentions switching to penalisation as an alternative to occlusion if wearing a patch is problematic.

What are the implications?

The findings from this review support both occlusion and atropine eyedrops as suitable methods for improving visual acuity and binocular function in those with a lazy eye.

However, using drops may result in better adherence and quality of life for the child. The choice of treatment and balance of risks should be discussed according to child and parental preferences.

Citation and Funding

Li T, Qureshi R and Taylor K. Conventional occlusion versus pharmacologic penalization for amblyopia. Cochrane Database Syst Rev. 2019;(8):CD006460. 

 

This study was funded by a number of sources including the National Institute for Health Research; National Eye Institute, National Institutes of Health, USA; and the John Hopkins Bloomberg School of Public Health, USA.

Bibliography

NHS website. Lazy eye. London: Department of Health; updated 2019.

NICE. Squint in children. Clinical Knowledge Summary. London: National Institute for Health and Care Excellence; 2016.

Why was this study needed?

Amblyopia is the commonest vision deficit in children, affecting about 2 in 100 children in the UK. It happens when the connection between the eye and the brain is impaired, but the eye itself is healthy.

Patching (occlusion), in which a patch is placed on the stronger eye for a number of hours, is the most common method of treatment. Another accepted method is the use of atropine eye drops (penalisation) which works by temporarily blurring eyesight in the better eye.

The researchers updated the previous version of this review, first published in 2009, using new evidence to compare the effectiveness and safety of patching compared with atropine drops for the treatment of a lazy eye.

What did this study do?

This systematic review included seven trials comparing patching with atropine drops in participants with a lazy eye, regardless of the severity of the condition. Only randomised controlled trials and quasi-randomised controlled trials were selected for inclusion.

The trials included 1,177 participants between 2 and 20 years of age. They were conducted in six countries, but no trials were from the UK. Four new trials were added to the original 2009 review. Treatment for at least two hours per day was given for 17 weeks to two years. 

Differences in starting vision between trials and varying treatments prevented meta-analysis and may affect the interpretation of the findings from this review, but the research was of adequate quality.

What did it find?

  • Evidence from six of the seven trials showed that both the patch and atropine drops produced an improvement in visual acuity in the weaker eye in the short-term (one to six months) and in the long-term (24 months). The magnitude of improvement varied between trials, and the results could not be pooled.

  • There was no meaningful difference between the two treatments in improving visual acuity or binocular function. 

  • Although use of the patch and the drops were generally well tolerated, the drops were associated with better adherence and quality of life.

  • Side effects included reduced visual acuity in the stronger eye, which was more common in those using atropine, but this did not require treatment in nearly all cases. Light sensitivity was also experienced after atropine drops. Eyelid irritation was more common when using a patch.

What does current guidance say on this issue?

The 2016 NICE Clinical Knowledge Summary on the topic of squints in children also covers the treatment of lazy eye.

It suggests that both occlusion and penalisation are options but also mentions switching to penalisation as an alternative to occlusion if wearing a patch is problematic.

What are the implications?

The findings from this review support both occlusion and atropine eyedrops as suitable methods for improving visual acuity and binocular function in those with a lazy eye.

However, using drops may result in better adherence and quality of life for the child. The choice of treatment and balance of risks should be discussed according to child and parental preferences.

Citation and Funding

Li T, Qureshi R and Taylor K. Conventional occlusion versus pharmacologic penalization for amblyopia. Cochrane Database Syst Rev. 2019;(8):CD006460. 

 

This study was funded by a number of sources including the National Institute for Health Research; National Eye Institute, National Institutes of Health, USA; and the John Hopkins Bloomberg School of Public Health, USA.

Bibliography

NHS website. Lazy eye. London: Department of Health; updated 2019.

NICE. Squint in children. Clinical Knowledge Summary. London: National Institute for Health and Care Excellence; 2016.

Conventional occlusion versus pharmacologic penalization for amblyopia

Published on 29 August 2019

Li, T.,Qureshi, R.,Taylor, K.

Cochrane Database Syst Rev Volume 8 , 2019

BACKGROUND: Amblyopia is defined as impaired visual acuity in one or both eyes without demonstrable abnormality of the visual pathway, and is not immediately resolved by wearing glasses. OBJECTIVES: In performing this systematic review, we aimed to synthesize the best available evidence regarding the effectiveness and safety of conventional occlusion therapy compared to atropine penalization in treating amblyopia. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 8); Ovid MEDLINE; Ovid Embase; LILACS BIREME; ClinicalTrials.gov; ISRCTN; and the WHO ICTRP on 7 September 2018. SELECTION CRITERIA: We included randomized/quasi-randomized controlled trials comparing conventional occlusion to atropine penalization for amblyopia. DATA COLLECTION AND ANALYSIS: Two review authors independently screened abstracts and full-text articles, abstracted data, and assessed risk of bias. MAIN RESULTS: We included seven trials (five randomized controlled trials and two quasi-randomized controlled trials) conducted in six countries (China, India, Iran, Ireland, Spain, and the United States) with a total of 1177 amblyopic eyes. Three of these seven trials were from the original 2009 version of the review. We assessed two trials as having a low risk of bias across all domains, and the remaining five trials as having unclear or high risk of bias for some domains.As different occlusion modalities, atropine penalization regimens, and populations were used across the included trials, we did not conduct any meta-analysis due to clinical and statistical heterogeneity. Evidence from six trials (two at low risk of bias) suggests that atropine penalization is as effective as conventional occlusion in improving visual acuity. Similar improvement in visual acuity was reported at all time points at which it was assessed, ranging from five weeks (improvement of 1 line) to 10 years (improvement of greater than 3 lines). At six months, although most participants (363/522) come from a trial rated as at low risk of bias with a precise estimate (mean difference (MD) 0.03, 95% confidence interval (CI) 0.00 to 0.06), two other trials rated as at high risk of bias produced inconsistent estimates and wide confidence intervals (MD -0.02, 95% CI -0.11 to 0.07 and MD -0.14, 95% CI -0.23 to -0.05; moderate-certainty evidence). At 24 months, additional improvement was found in both groups, but there continued to be no meaningful difference between those receiving occlusion and those receiving atropine therapies (moderate-certainty evidence).We did not find any difference in ocular alignment, stereo acuity, or sound eye visual acuity between occlusion and atropine penalization groups (moderate-certainty evidence). Both treatments were well tolerated. Atropine was associated with better adherence (moderate-certainty evidence) and quality of life (moderate-certainty evidence), but also a higher reported risk of adverse events in terms of mild reduction in the visual acuity of the sound eye not requiring treatment and light sensitivity (high-certainty evidence). Skin, lid, or conjunctival irritation were more common among participants receiving patching than those receiving atropine (high-certainty evidence). Atropine penalization costs less than conventional occlusion. AUTHORS' CONCLUSIONS: Both conventional occlusion and atropine penalization produce visual acuity improvement in the amblyopic eye. Atropine penalization appears to be as effective as conventional occlusion, although the magnitude of improvement differed among the trials we analyzed.

Expert commentary

This review delivers important findings: atropine blurring is as effective as patching in improving vision in the amblyopic eye and has a lasting effect. This means that practitioners can confidently offer parents the choice of either modality as first-line treatment after glasses. 

Importantly, the review also highlights the risk of reducing vision in the better-seeing eye, reminding practitioners that close monitoring is required for children receiving atropine treatment. Lastly, it is a welcome finding that atropine treatment improves children’s quality of life.

For researchers, the review is a reminder to either use outcomes which enable meta-analysis across trials or to share primary data.

Annegret Dahlmann-Noor, Honorary Clinical Associate Professor; Consultant in Paediatric Ophthalmology and Strabismus; Clinical Trials Lead in Paediatric Ophthalmology, NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology.

The commentator declares no conflicting interests