Two studies conducted in collaboration with Orbis International explore how providing free glasses to children improves their ability to learn in school and that addressing visual impairment in children can alleviate depression and anxiety.
Vision impairment and blindness affect 2.2 billion people worldwide, including 19 million children. For these children, vision impairment can considerably impact their life, including their educational attainment and mental health.
Two studies conducted in collaboration with eye care non-profit Orbis International conclude that 1) providing free glasses to children improves their ability to learn in school and that 2) addressing visual impairment in children can alleviate depression and anxiety.
Both of these studies fill important research gaps and also provide essential guidance for future interventions and research.
Glasses and education for children
The first study, published in The BMJ, was conducted in rural western China, where only 15% of children needing glasses have them. The study was a cluster randomized controlled trial (RCT), double-masked, and cross-arm contamination was minimized by selecting one school per township. Primary schools in two neighboring provinces, Gansu and Shaanxi, were considered for eligibility. Sampled areas included low- and middle-income townships in each province. In total, 252 schools were selected – one per township, and one fourth and fifth grade class from each school was selected. Children in these selected classes were eligible to participate in the study if their uncorrected visual acuity was £6/12 in either eye and could be improved to ³6/12 in both eyes by wearing glasses.
The researchers began by providing questionnaires to children, parents, and mathematics teachers. The questionnaires for the children asked about their vision and personal information. The questionnaires for parents and teachers asked about wealth and blackboard use, respectively. Visual acuity for each child was assessed at the beginning of the study.
Then, automated refraction with subjective refinement was performed on the children with uncorrected visual acuity £6/12. Mathematics scores were assessed at the beginning and the end of the study using separate timed and proctored exams appropriate for each grade. Glasses wear was assessed at the end of the study through direct examination and self-report measures.
The schools were randomized to receive one of three interventions: free glasses, vouchers for free glasses, or a prescription (the control group). Children in the voucher and control groups received free glasses at the conclusion of the study if needed, but were not initially informed of this.
The schools were further randomized into two groups: those that received education encouraging glasses wear (such as watching a video, receiving a brochure, or a classroom discussion) or that received no education. All information was created to express that myopia is common in China, glasses are the safest and most effective treatment, and wearing glasses does not harm children’s eyes. Ultimately, 3,177 children in 251 schools were eligible to participate in the study. Only 15% of eligible children already wore glasses. At the end of the study, 41% of children in the free glasses group were observed wearing glasses, while 68% self-reported wear. Comparatively, 26% were observed and 37% self-reported wear in the control group.
Providing free glasses to children improved math test scores equivalent to half a semester of extra teaching. Improvement was especially pronounced when half or more of teaching utilized blackboards (a plausible result, as these children were mostly myopic and thus at a special disadvantage when reading from a distant blackboard, as opposed to a textbook on their desk). Provision of free glasses impacted test scores more than parental education and family wealth. This effect was seen even with imperfect compliance (about 40% in this case), but further encouragement of glasses wearing can be expected to further increase impact.
This study provides a rationale for cost-effective government programs to provide free glasses to school children. The low cost of bulk-bought glasses increases affordability for government programs; pilot programs providing free glasses to children have started in Gansu and Shaanxi provinces as a result of this study. The study also helped to catalyze a 2018 Chinese national myopia control program announced by none other than Xi Jinping.
The link between vision impairment and mental health
The second study, published in Ophthalmology, demonstrated that children with visual impairment have higher rates of depression and anxiety than their peers without visual impairment. Myopic children specifically have higher depression and anxiety scores, and those with other causes of vision impairment have higher anxiety scores. Additionally, it was shown that children who receive corrective strabismus surgery have improved depression and anxiety symptoms. This study provides clear evidence that can guide governments to take action on children’s vision, especially related to providing glasses and insurance coverage for corrective strabismus surgery when the cost is otherwise prohibitive.
Depression and anxiety pose a greater risk to children when not identified and corrected promptly. The lifetime burden in terms of years affected by these conditions is also much higher in children. Orbis’s study posits that the mental health of children with vision impairment may be adversely affected because they tend to participate in fewer physical activities, have lower academic achievement, and are more socially isolated. In addition, negative attitudes toward strabismus seem to emerge as early as six years of age, and early detection and treatment may impact children’s mental health profoundly.
This study reported on a systematic review and meta-analysis to investigate whether vision impairment, ocular morbidity, and their treatments are associated with mental health problems in children, specifically depression and anxiety. The study analyzed 36 articles from nine different databases. These articles analyzed studies involving children and young adults who underwent ophthalmic interventions and provided a narrative summary of mental health findings in adults with vision impairment (visual acuity <6/12) or ocular morbidity as children.
The study evaluated 23 observational studies related to depression and anxiety, eight observational studies related to strabismus, and seven interventional studies. In all, nearly 700,000 participants were enrolled in these studies. Of the 36 studies, 22 were from low- to middle- income countries, and nine of these focused on myopia in China.
While there is an existing large body of work focused on the impact of vision impairment on depression and anxiety in adults, studies investigating mental health in children with vision impairment are few and have not previously been reviewed in this comprehensive way. This research has profound implications for health care planners when allocating resources and designing interventions to curb vision impairment.
For example, in some countries, strabismus surgery is seen as a cosmetic procedure and excluded from insurance coverage, forcing families to pay out-of-pocket. These barriers could deter patients of low socioeconomic status from seeking treatment and keep the mental health benefits of corrective surgery out of reach. More accessible eye care treatments will improve children's mental health and overall well-being.
These studies provide important information on the effect of avoidable vision impairment and blindness on children’s educational outcomes and mental health. Uncorrected refractive error continues to be the leading cause of vision loss in the world. The inability to see clearly and the proven impact of poor vision on educational performance may be a source of anxiety and depression, especially in highly pressurized educational environments like China, where more than half of children aged 6 to 18 have myopia.
Ultimately, the results of both studies provide policymakers and healthcare planners with important information for intervention design and resource allocation as they highlight the negative impacts of visual impairment and the positive impacts of treatment.