Key messages

• In general, none of the interventions reliably improved adherence to amblyopia treatment (specifically patching) in children. The interventions investigated also showed no evidence of improvement in vision or depth perception (judging how far away things are or '3-D vision').

• Barriers to accessing treatments or appointments can impact how well children and their caregivers can carry out amblyopia treatment.

• More structured ways to track adherence are needed, as well as making reporting results about following treatment plans, vision, and depth perception more consistent.

What is amblyopia?

Amblyopia is a technical term for reduced vision caused by abnormal visual development early in life. This results in not seeing as well with one or, less often, both eyes, even with optimal prescription eyeglasses or contact lenses. This is sometimes referred to as 'lazy eye' by parents and caregivers.

What did we want to find out?

Adherence means how closely the amount of treatment completed matches the amount the healthcare provider prescribed. Adherence can be measured subjectively (e.g. by diary) or objectively (e.g. by sensing temperature contact with the skin). Examples of barriers to adherence include understanding the treatment, time, transportation, and availability or cost of the treatment or medical visits. We wanted to find out if any methods used to increase adherence to amblyopia treatment were successful and if any caused harm. In cases of amblyopia in one eye, treatment often consists of patching (covering or blocking) the better-seeing eye. This can be hard for children and their caregivers. Methods or interventions that we explored were behavioral, digital (i.e. technological or electronic, like playing a video game or watching a show), and different approaches to patching.

What did we do?

We searched for studies that investigated: 1) a single or a combination of behavioral interventions, like educational cartoons and text message reminders; 2) digital stimulus interventions, like videos or video games; or 3) using different types of patches, like shutter glasses or different materials of patches, compared with the standard of care or no intervention (i.e. no method used to improve adherence).

What did we find?

We found that most of the ways researchers tried to increase adherence were no different from each other. The evidence was uncertain, and so we were unable to draw conclusions that any one approach was better than any other.

What are the limitations of the evidence?

Few studies used objective tools to measure adherence. There was wide variation in the reporting of several characteristics and outcomes, including amblyopia severity, method of adherence monitoring, and follow-up duration, which had an impact on how confident we were in the evidence. Several outcomes related to adherence were not reported in each study and the clinical importance of the relative changes for these outcomes may vary by patient. Few studies assessed or reported on harms and factors related to fairness and inclusivity, such as socioeconomic status or caregiver education, with no standardization in reporting format.

How up-to-date is this evidence?

The evidence is up-to-date to the search date of 24 May 2024.