Preplanned Studies: A Multi-Center Cross-Sectional Study on Visual Impairment and Depression Among Students — Jiangsu Province, China, 2017–2022

Vision impairment is a significant global issue, affecting 2.2 billion individuals worldwide, including an estimated 19 million children aged 0–14 years. Of this group, approximately 1.4 million children suffer from irreversible blindness (1). In China, over half of children aged 6–18 years are affected by myopia, which can be attributed to the high-pressure educational environment they face (2). This vision impairment can have detrimental effects on their education and may contribute to the development of depressive symptoms (2). As vision is crucial for perceiving and comprehending the environment, impairments in this modality can negatively impact mental health, leading to anxiety, depression, or self-esteem issues. Particularly in the eastern China, where myopia prevalence is highest among children and adolescents, the link between visual health and psychological well-being is a significant public health concern that requires further investigation and ongoing attention.

The study was conducted from 2017 to 2022, with participation from 11 project sites. Random sampling of districts or counties was used to select these sites in Jiangsu Province, which consists of 98 districts or counties. During the research period, a total of 8,997 middle and high school students across 6 grade levels participated in the survey. For more detailed information on the survey process (Figure 1).

Figure 1. 

The flowchart illustrates the research procedure involving middle and high school students from 2017 to 2022.

Abbreviation: CES-D=Center for Epidemiologic Studies Depression Scale; BMI=body mass index.

The survey comprised several components. First, ophthalmic examinations were conducted by trained program members, nurses, and doctors. The myopia screening institution needed to have a valid medical institution license. Visual impairment, referred to as low vision, was assessed using the “Standard Logarithmic Visual Acuity Chart” (GB 11533–2011) (3). Visual acuity of 5.0 or more indicated health vision in children and adolescents aged 6 and above. Visual acuity ranging from 4.6 to 4.9 was considered as mild to moderate visual impairment, while visual acuity equal to or less than 4.5 was classified as severe visual impairment. The severe visual impairment group was further categorized into severe vision impairment group 1 (visual acuity ≤4.0) and severe vision impairment group 2 (visual acuity ranging from 4.1 to 4.5). Second, height and weight measurements were taken. Students removed their shoes and clothes before their weight and height were measured. The measurements were taken according to the standardized equipment and procedures outlined in the health check list for primary and junior school students (GB 16134–2011) (4). Overweight, obesity, and body mass index (BMI) screening followed the unified classification criteria based on the screening for overweight and obesity among school-age children and adolescents (WST 586–2018) issued by the National Health Commission of the People’s Republic of China. BMI was calculated as weight in kilograms divided by height in meters squared. Third, the prevalence of depressive symptoms was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D) (5). The CES-D scale, which has been widely used and validated for reliability in Chinese cohorts, was utilized. The Chinese version of the CES-D scale employs a four-point Likert scale, with higher scores indicating more severe depressive symptoms. A CES-D score of 20 or higher was used as the threshold to identify the presence of depressive symptoms (6). Finally, a comprehensive questionnaire was administered to collect baseline data, including information on date of birth, family structure, outdoor activity levels, exposure to passive smoking, and other relevant factors.

The characteristics of the participating students were described as follows: 1) Continuous variables such as age, BMI, and sleep duration, which followed a normal distribution, were presented as mean±standard deviation. 2) Categorical variables, including resident students, single-parent household, and passive smoking, were analyzed using chi-square tests and presented as percentages. 3) Multilevel logistic models were used to investigate the association between visual impairment and symptoms of depression. The analysis included the following covariates: age, gender, region, resident students, family type (single-parent household), BMI, passive smoking, sleep duration, physical activity (more than 2 hours of daily outdoor activity), child growth development, and year. Odds ratios (ORs) along with their corresponding 95% confidence intervals (CIs) were calculated. Data analysis was performed using IBM SPSS (version 20.0; IBM Corp., Armonk, NY, US). Statistically significant results were defined as P-value <0.05.

This study included 8,997 participants between 2017 and 2022. The average age of the participants was 14.4±1.7 years. Of the total participants, 4,745 (52.7%) were male students and 4,619 (51.3%) were urban children and adolescents. Comparing the group with low depression scores (CES-D<20) to the high depression score group (CES-D≥20), several significant distinguishing characteristics were found. Table 1 provides a detailed overview of these differences.

We conducted a pooled analysis to examine the association between visual impairment and depressive symptoms. Three models were used: Model 1 with no covariates, Model 2 with covariates such as age, gender, region, and year, and Model 3 with a comprehensive set of covariates including age, gender, region, resident students, family type, BMI, passive smoking, sleep duration, physical activity, and child growth development, along with year. In Model 3, compared to the healthy vision group (visual acuity ≥5.0), the ORs for the severe vision impairment group 1 (≤4.0), severe vision impairment group 2 (visual acuity between 4.1 and 4.5), and mild and moderate visual impairment group (visual acuity between 4.6 and 4.9) were 1.90 (95% CI: 1.53–2.37), 1.53 (95% CI: 1.24–1.88), and 1.46 (95% CI: 1.16–1.84), respectively. These findings indicate a significant population-level association between vision impairment and depressive symptoms among Chinese students (Figure 2).

Figure 2. 

Forest plot depicting the association between visual impairment and depressive symptoms. (A) Relationship between visual impairment and depressive symptoms with Model 1; (B) relationship between visual impairment and depressive symptoms with Model 2; (C) relationship between visual impairment and depressive symptoms with Model 3; (D) relationship between visual impairment (4.6–4.9) and depressive symptoms with Model 3 sorted by regions; (E) relationship between visual impairment (4.1–4.5) and depressive symptoms with Model3 sorted by regions; (F) relationship between visual impairment (≤4.0) and depressive symptoms with Model 3 sorted by regions.

Abbreviation: OR=odds ratio; CI=confidence interval; BMI=body mass index.