Association between myopia and anxiety: a cross-sectional study based on Chinese university freshmen
Highlight box
Key findings
• There was no significant correlation between myopia and anxiety in college student.
What is known and what is new?
• Previous studies have demonstrated that vision impairment has a negative impact on the mental health of adults.
• We studied the relationship between these two factors among young college students, and found that myopia seemed to have little effect on mental health.
What is the implication, and what should change now?
• Considering the observational design of our study, the results should be validated in further studies with a larger sample size.
Introduction
At least 1 billion people are affected by blindness or vision impairment worldwide, and in China, the proportion of myopia among college students is even higher (1). Myopia may have a negative impact on students’ mental health because physical activity is more difficult, academic performance is affected, and they may be more socially isolated (2). Vision impairment has been associated with the incidence of anxiety (3-6), but studies have mostly focused on older people (>60 years) and data specific to college students are limited.
Although compared with older people, the risk of anxiety among college students is much lower, the increased academic pressure during these years of study can become a psychological burden. The mental health of college students is affected by many factors, such as employment, economic, and emotional pressure. In addition, bad campus culture and inappropriate education methods may also have negative effects on students’ mental health. Possibly due to these reasons, depression, anxiety and self-harm are becoming more and more common among college students (7-10), which indicates the importance of paying attention to their mental health. Few studies have focused solely on myopia rather than impaired vision; other research has revealed the impact of common chronic ocular morbidities, such as strabismus, on mental health in adults. However, college freshmen are a special group of young adults who have experienced the great challenges of college entrance examination, entering a new environment, and facing social development transformation. And unfortunately, few studies have focused on the effects of myopia on college freshmen’s mental health, possibly due to that myopia has become commonplace in today’s society, and college freshmen are generally considered as the most energetic group of people, who are considered to be not so likely to suffer from mental problems. Here, we hypothesized that myopia in college students might have an impact on their mental health. Although myopia is not as serious as vision impairment, its impact should not be underestimated, considering its high incidence rate. Exploring the relationship between myopia and anxiety will help us better understand the mental health of college students, and help the public pay more attention to the prevention of myopia and mental diseases. We present the following article in accordance with the STROBE reporting checklist (available at https://atm.amegroups.com/article/view/10.21037/atm-23-743/rc).
Methods
Study design
We conducted a large cross-sectional study focused on freshmen enrolled in September 2021 in a Chinese university. We focused on college freshman but not all college students since freshman are a special group of young adults who have experienced the great challenges of college entrance examination, entering a new environment, and facing social development transformation. A total of 5,519 college freshman would be assessed for the eligibility of the present study. The major method of the study and data collection was by questionnaires, which comprised the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25), the Self Esteem Scale (SES), the Self Rating Anxiety Scale (SAS), the Self Rating Depression Scale (SDS), and the Social Avoidance and Distress Scale (SAD). In addition, a socio-demographic questionnaire was designed and utilized to collect corresponding information. All enrollees were required to complete all the above questionnaires. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). Informed consent was taken from all the participants.
Participant selection
The inclusion criteria of this study were: (I) first-year college student; (II) diagnosed as myopia and emmetropia through vision test; (III) gave informed consent. The exclusion criteria were: (I) previous eye disease history, with definite diagnosis of acute and chronic conditions affecting vision other than myopia (hereditary retinoschisis, etc.); (II) history of eye surgery, ophthalmic drugs in the last one year or psychiatric trauma.
Study protocol
All ocular examinations were performed and recorded by an ophthalmologist. Participants underwent a routine ocular examination, including naked eyesight, corrected eyesight, eye location, foregoing proportion and bottom inspections. Next, the students were examined with mydriasis and optometry (two drops of compound tropicamide eye drops in both eyes every 5 min; after 20 min, if there was still pupillary light reflection, another drop was instilled then). The light catoptric and pupillary inflation were inspected after an interval of 15 min. The inflation and light reflection were registered 40–60 min after the first drops. If the pupil enlarged by ≥6 mm and there was no light reflection, mydriasis was successful. A Topcon KR-8900 Automatic Refractive Keratometer (optometer) was used to perform computer optometry for all students. The spherical equivalent (SE) mirror degree was calculated as the algebraic sum of 0.5 × SE and the cylindrical mirror degree (i.e., equivalent SE = 0.5 × SE + cylindrical mirror degree). In line with the lens equivalent SE value of the subject and the national standard for refractive status, emmetropia means normal vision, defined as binocular naked eye vision ≥5.0. In line with the equivalent SE value of the subject, myopia was defined as the naked eye vision <5.0 in either eye, and the equivalent SE of computer optometry under non-ciliary muscle paralysis <50 D. If one eye was myopic and the other was hyperopic, vision was still defined as myopia. Myopic students were divided into four groups: mild myopia group (MG, SE <300 D), secondary MG (SE 300–<600 D), severe MG (SE 600–900 D) and ultra-high myopia (SE >900 D) (Table 1).
Table 1
| Content | Mild MG | Secondary MG | Severe MG | Ultra-high MG |
|---|---|---|---|---|
| SE scale (D) | <300 | 300–<600 | 600–900 | >900 |
MG, myopia group; SE, spherical equivalent; D, degree.
For the data processing we used the double entry mode, and a third person would enter the final data. If any suspicious answers were found, the original questionnaire was checked and verified again. Each questionnaire had a unique number, which would be randomly selected for review.
Questionnaire content
NEI-VFQ-25
The NEI-VFQ-25 is a self-reported vision-related quality of life assessment (11). The missing rate of the driving dimension is high in Asian countries, so it was deleted in the present survey.
SES
SES is a 10-item self-reported measure of self-worth or self-acceptance. The items are answered on a 4-point scale ranging from strongly approve to strongly disapprove (12).
SAS
The Zung SAS measures somatic symptoms associated with anxiety. The scale is centered on 4 common disorders: anxiety and panic; vestibular manifestations; somatic control; and gastrointestinal/muscular sensations (13).
SDS
SDS is a 20-item measure, with each item bears a 4-point scale, which demands around 5–10 mins to accomplish. Gentle to secondary depression, secondary to severe depression, and senior depression ranged from 50–59, 60–69, and above 70, respectively (14).
SAD
SAD is a 28-item true/false scale that measures solitude. Wanting to escape or avoid being around, talking to, or interacting with other people for any reason is called social avoidance (15).
Statistical analysis
The Shapiro-Wilk test was first fulfilled to conclude if the data were evenly distributed. Outliers were detected using boxplots and removed from subsequent analysis to reduce the bias. The correlation between the anxiety-associated factors and myopia-associated factors was determined using Pearson correlation analysis if both factors were normally distributed; otherwise, Spearman correlation analysis was performed. All statistical analyses were performed using R software (Version 4.2.0). A P value <0.05 was considered statistically significant. All the P values in the present study are two-sided.
Results
Baseline characteristics
A total of 5,519 college students were registered, and 4,984 students were finally enrolled, as shown in Figure 1. The general baseline information of these participants, such as female/male ratio, age, myopia degree, course of myopia, course of wearing glasses, daily sleep duration, daily outdoor activity duration, and daily duration of using of electronic products, are summarized in Table 2. All continuous variables were normally distributed, so Pearson correlation analysis was performed to test the correlation.
Table 2
| Characteristics | n | % |
|---|---|---|
| Total | 5,519 | 100 |
| Sex | ||
| Male | 3,335 | 60.43 |
| Female | 2,184 | 39.57 |
| Age, years | 19.8 | – |
| Myopia degree of right eye | ||
| Not nearsighted | 977 | 17.70 |
| <300° | 1,607 | 29.12 |
| 300–<600° | 2,430 | 44.03 |
| 600–900° | 484 | 8.77 |
| >900° | 21 | 0.38 |
| Myopia degree of left eye | ||
| Not nearsighted | 1,111 | 20.13 |
| <300° | 1,611 | 29.19 |
| 300–<600° | 2,324 | 42.11 |
| 600–900° | 450 | 8.15 |
| >900° | 23 | 0.42 |
| Course of myopia, years | ||
| Not nearsighted | 835 | 15.13 |
| <1 | 184 | 3.33 |
| 1–<3 | 805 | 14.59 |
| 3–<5 | 1,560 | 28.27 |
| 5–10 | 1,769 | 32.05 |
| >10 | 366 | 6.63 |
| Course of wearing glasses, years | ||
| <1 | 1,291 | 23.39 |
| 1–<3 | 897 | 16.25 |
| 3–<5 | 1,505 | 27.27 |
| 5–10 | 1,560 | 28.27 |
| >10 | 266 | 4.82 |
| Daily sleep duration, h | ||
| <7 | 1,885 | 34.15 |
| 7–9 | 3,511 | 63.62 |
| >9 | 123 | 2.23 |
| Daily outdoor activity, h | ||
| <1 | 2,107 | 38.18 |
| 1–2 | 2,832 | 51.31 |
| >2 | 580 | 10.51 |
| Daily use of electronic devices, h | ||
| <2 | 322 | 5.83 |
| 2–<4 | 1,646 | 29.82 |
| 4–<6 | 1,761 | 31.91 |
| 6–8 | 1,064 | 19.28 |
| >8 | 726 | 13.15 |
| Monthly household income, ¥ | ||
| <1,000 | 339 | 6.14 |
| 1,000–<3,000 | 1,252 | 22.69 |
| 3,000–<5,000 | 1,865 | 33.79 |
| 5,000–9,000 | 1,431 | 25.93 |
| >9,000 | 632 | 11.45 |
Association between myopia and questionnaire scores
NEI-VFQ-25 score
As showed in Figure 2, both right and left vision had a statistically significant association with NEI-VFQ-25 score (P=0.006 and P=0.021, respectively; Pearson correlation analysis). However, both correlation coefficients were less than 0.1 (r=0.070 and r=0.060, respectively; Pearson correlation analysis).
SES score
As shown in Figure 3, no remarkable association was found between SES score and eye vision, no matter if the right eye (RE, P=0.877) or left eye (LE, P=0.719).
SAS score
As shown in Figure 4, both right and left vision had a statistically significant correlation with SAS score (P=0.003 and P=0.004, respectively). However, both correlation coefficients were less than 0.1 (r=0.075 and r=0.075, respectively).
SDS score
As shown in Figure 5, no remarkable association was found between SDS score and eye vision, whether the RE (P=0.226) or LE (P=0.402).
SAD score
As shown in Figure 6, no remarkable association was established between SAD score and eye vision, whether the RE (P=0.758) or LE (P=0.562).
Discussion
We found a significant association between vision and the NEI-VFQ-25 and SAS scores, but the correlation coefficients were very low, which indicated that although myopia had an impact on the students’ mental health, the impact was not great. Additionally, no remarkable association was established between myopia and other anxiety-associated scales such as SES, SDS, and SAD.
Previous studies have demonstrated a link between vision impairment and anxiety in adults (3-6). In a recent systematic review, higher scores of depression and anxiety were associated with children’s vision impairment (16). However, the association between vision impairment and depression/anxiety has not been reported in young adults, such as college students. On entry to higher education, all college students experience a period of rapid psychological and physiological change, which may develop into an emotional disorder.
Thus, we hypothesized that myopia, although less severe than vision impairment, might affect the mental health of college students. However, our primary results indicated that the impact of myopia on mental health was very slight, even negligible, which negated our hypothesis. Although there was a significant correlation between vision and the NEI-VFQ-25 and SAS scores, the P value is greatly affected by the sample size. Therefore, based on the correlation coefficients, we concluded that there was no correlation between vision and the scores of the two scales. It was previously reported that the greater the degree of myopia, the higher the anxiety score. However, myopia was not found to be associated with depression. The inconsistency between our findings might be due to Bias caused by differences in sample size and geographical differences. In addition, that study was conducted during the COVID-19 pandemic, which might also have some impact on the final conclusions. Collectively, myopia seemed to have little effect on mental health, but considering that this was a cross-sectional study, its results only reflect the students’ status at a certain time point and there was not enough follow-up, so caution should be taken with accepting the conclusion.
We speculated that emotional anxiety may cause tension in the extraocular muscles. Prolonged tension in the extraocular muscles can easily lead to visual fatigue and insufficient eye regulation, which can lead to an increase in myopia when overused. Myopia may also cause anxiety through indirect effects. For example, nearsightedness may increase students’ academic pressure, and wearing glasses may increase appearance anxiety.
Considering the correlation between myopia and anxiety, we recommend that clinical physicians should pay attention to the psychological status of myopia patients and the visual health of anxiety patients, in order to prevent the mutual promotion of myopia and anxiety.
The strength of this study lies in the large sample size. The limitation lies in its study design. Cross-sectional studies are susceptible to interference from various confounding factors, and the causal relationship between variables cannot be inferred. Taken together, although our data suggested no significant correlation between myopia and anxiety, our results should be validated in further studies.
Conclusions
Our data suggested that there is no significant week correlation between myopia and anxiety. However, since this is a single-center study, the observed weak correlation may be caused by selection bias. Therefore, our results still need to be validated in further studies with a larger sample size.
Acknowledgments
Funding: None.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://atm.amegroups.com/article/view/10.21037/atm-23-743/rc
Data Sharing Statement: Available at https://atm.amegroups.com/article/view/10.21037/atm-23-743/dss
Peer Review File: Available at https://atm.amegroups.com/article/view/10.21037/atm-23-743/prf
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-23-743/coif). The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). Informed consent was taken from all the participants.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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(English Language Editor: K. Brown)
