Child friendly tests can help monitor vision at home 

Since the COVID-19 pandemic, the interest in home vision testing increased. 

Remote consultations are seen as more convenient and cut travel and waiting time often experienced in hospital eye appointments. 

Remote assessment of vision can be particularly helpful for children and young people. It can reduce time away from school and parental time away from work or caring responsibilities. 

This is especially relevant for children undergoing amblyopia treatment (also known as lazy eye), who may have to have their vision checked every 8 – 12 weeks. 

Visual acuity, which is how clearly we can see and distinguish small details with precision at a distance, is the main clinical assessment of vision. 

Home monitoring of visual acuity in children has been successfully tested using printed tests, phone apps and web-based systems. 

For children with amblyopia and other vision impairments, assessment of contrast sensitivity function (CSF) is a more relevant and informing test.

CSF is the ability to perceive sharp and clear outlines of very small objects, and identify minute differences in the shadings and patterns. It allows us to distinguish objects without a clear outline from their background. 

CSF is important in performing everyday tasks as diverse as reading, writing, recognising faces, telling the time on a clock, walking, balancing, pouring liquids and using kitchen utensils. 

In children with amblyopia CSF is reduced, even after treatment has restored visual acuity to normal levels.

In those with vision impairment, CSF has been shown to better predict visual function and disease progression.

Despite its relevance in the detection and monitoring of amblyopia, home testing of contrast sensitivity in children has not been previously assessed.

In this study funded through our springboard award, Dr Jones and team have shown that children are able to measure their CSF using tablet-or paper-based tests.

Forty children, aged 5–15 years, with amblyopia (10 children), other vision impairment (10 children) or good vision (20 children) measured their own vision using three distinct CSF tests: Manifolds optotype test, PopCSF gamified test, and Spotchecks paper based test.

Children performed the tests in a laboratory with minimal supervision. Children with good vision or amblyopia did all three tests with one eye at a time, with the fellow eye patched. 

Completion rate, test repeatability, duration and participants’ preferences were recorded for each test. Test times were 2–4 min per eye.

Measuring visual acuity provides a quick and informative test of visual function in the clinic. 

For home use, where test duration is not limited by clinician time, the findings of this study suggest using the more detailed assessment of visual function offered by contrast sensitivity testing. 

This is particularly relevant in children receiving treatment for amblyopia and those with other vision impairments.

Young children with and without eye disease were able to test their CSF with minimal supervision and repeatable results, which provides proof of concept for performing these tests at home. 

The next phase of this study is to try out these tests in a home setting, which will enable the researchers to compare CSF measurements from the laboratory to those obtained at home.

Our springboard awards are designed to help researchers develop new ideas and take the next step in their academic careers.

This springboard award and nation- and worldwide collaborations were instrumental in Dr Pete Jones obtaining a permanent lectureship at City, University of London, where he currently teaches biology of the eye to around 250 new and aspiring optometrists and nurses every year.

This appointment is Dr Jones’s first permanent faculty position and made him eligible to supervise PhD students and apply for external grant funding. 

Since 2021 he has supervised 3 PhD students, and successfully raised £500,000 in grant funding towards the continuing development and validation of new, portable, child-friendly vision tests for use in and outside of conventional eye care facilities.

The novel vision-testing technologies developed during this springboard grant are now vital tools, trialled worldwide as a way of providing ongoing vision monitoring in a number of settings.

The convenience of these self-administered tests means that they can also be deployed in clinics, as means of better using patients’ time and improving patients’ experience.