Is Dietary Vitamin A Associated with Myopia from Adolescence to Young Adulthood?

Reduced retinol (vitamin A) and α-tocopherol (vitamin E) blood levels and increased myeloperoxidase (MPO) activity in children with high myopia

The study assessed selected parameters of redox status in the plasma of patients suffering from high myopia (HM). Thirty-five children with mean age 13.7 ± 2.7 years with HM and 40 healthy children were included. Plasma redox status parameters were determined using colorimetric kits. The levels of retinol, α-tocopherol and coenzyme Q10 were determined with a high-performance liquid chromatograph. Negative correlations were observed between the concentrations of retinol and the axial length of the eye (r = - 0.514 p < 0.001). Increased myeloperoxidase (MPO) activity (p < 0.018), and decreased concentrations of retinol (p < 0.001) and α-tocopherol (p < 0.023) in patients with HM and the axial length of the eye > 26 mm compared to controls were established. Significantly lower retinol and α-tocopherol concentrations were found in patients with the axial length of the eye > 26 mm compared to those with the axial length of the eye ≤ 26 mm (p < 0.001, p < 0.021, respectively). Increased MPO activity in advanced stages of HM may confirm an inflammatory process in HM patients. Reduced retinol and α-tocopherol concentrations and their link to disease progression indicate a need for monitoring their levels and supplementation in children with HM.

Correlation analysis of myopia and dietary factors among primary and secondary school students in Shenyang, China

Currently, the global prevalence of myopia is high and on the rise, seriously affecting the health of students. Studies have suggested that dietary factors may be associated with the occurrence and development of myopia, but the results are inconsistent. This survey aims to analyze the correlation between dietary factors and myopia while controlling for more confounding factors. A multi-stage stratified cluster sampling method was performed to select 10,619 primary and secondary school students in Shenyang for visual examination, and questionnaires were administered to 6974 of them. Logistic regression was performed with myopia as the dependent variable and the variables with p < 0.1 in the univariate analysis as independent variables. Sensitivity analysis was conducted using propensity score matching. The results showed that the overall prevalence of myopia among primary and secondary school students in Shenyang was 59.1%, with mild myopia predominating. Students who ate fresh fruits two or more times a day had a 0.69 times lower risk of myopia compared to those who did not eat fruits (95% CI 0.50-0.97). However, subgroup analysis demonstrated that this protective effect was only significant for male students, with an OR of 0.59 (95% CI 0.38-0.91). Moreover, female students who consumed sugary beverages once or more a day had a 1.8 times higher risk of myopia compared to those who did not consume sugary beverages (95% CI 1.03-3.15). Vegetable consumption, intake of fried foods, and breakfast habits were not significantly associated with myopia. In summary, excessive consumption of sugary beverages could increase the risk of myopia, especially in female students, whereas fruit intake contributed to reducing the risk of myopia, particularly in male students.

No Evidence of an Association between Genetic Factors Affecting Response to Vitamin A Supplementation and Myopia: A Mendelian Randomization Study and Meta-Analysis

The relationship between vitamin A supplementation and myopia has been a topic of debate, with conflicting and inconclusive findings. We aimed to determine whether there is a causal relationship between vitamin A supplementation and the risk of myopia using Mendelian randomization (MR) and meta-analytical methods. Genetic variants from the UK Biobank and FinnGen studies associated with the response to vitamin A supplementation were employed as instrumental variables to evaluate the causal relationship between vitamin A supplementation and myopia. Fixed-effects meta-analysis was then used to combine MR estimates from multiple sources for each outcome. The meta-analysis of MR results found no convincing evidence to support a direct causal relationship between vitamin A supplementation and myopia risk (odds ratio (OR) = 0.99, 95% confidence interval (CI) = 0.82-1.20, I2 = 0%, p = 0.40). The analysis of three out of the four sets of MR analyses indicated no direction of causal effect, whereas the other set of results suggested that higher vitamin A supplementation was associated with a lower risk of myopia (OR = 0.002, 95% CI 1.17 × 10-6-3.099, p = 0.096). This comprehensive MR study and meta-analysis did not find valid evidence of a direct association between vitamin A supplementation and myopia. Vitamin A supplementation may not have an independent effect on myopia, but intraocular processes associated with vitamin A may indirectly contribute to its development.

Association Between Serum Vitamin D Levels and Myopia in the National Health and Nutrition Examination Survey (2001-2006)

PURPOSE

To assess the relationship between serum vitamin D levels and myopia in people aged 12-50 years using the National Health and Nutrition Examination Survey (NHANES) database.

METHODS

Demographics, vision, and serum vitamin D levels from NHANES (2001-2006) were analyzed. Multivariate analyses were performed to examine the relationship between serum vitamin D levels and myopia while controlling for sex, age, ethnicity, education level, serum vitamin A, and poverty status. The main outcome was presence or absence of myopia, defined as a spherical equivalent of -1 diopters or more.

RESULTS

Of the 11669 participants, 5,310 (45.5%) had myopia. The average serum vitamin D concentration was 61.6 ± 0.9 nmol/L for the myopic group and 63.1 ± 0.8 nmol/L for the non-myopic group (p = .01). After adjusting for all covariates, having higher serum vitamin D was associated with lower odds of having myopia (odds ratio 0.82 [0.74-0.92], p = .0007). In linear regression modeling that excluded hyperopes (spherical equivalent > +1 diopters), there was a positive relationship between spherical equivalent and serum vitamin D levels. Specifically, as serum vitamin D doubled, spherical equivalent increased by 0.17 (p = .02) indicating a positive dose-response relationship between vitamin D and myopia.

CONCLUSIONS

Participants with myopia, on average, had lower serum concentrations of vitamin D compared to those without myopia. While further studies are needed to determine the mechanism, this study suggests that higher vitamin D levels are associated with lower incidence of myopia.

The influence of the environment and lifestyle on myopia

BACKGROUND

Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia.

MAIN BODY

Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development.

CONCLUSION

The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.

Association between dietary nutrient intake and prevalence of myopia in Korean adolescents: evidence from the 7th Korea National Health and Nutrition Examination Survey

Background

The rise in myopia prevalence, particularly among adolescents in East Asia, is a cause for concern. While a combination of environmental and genetic factors is understood to contribute to this trend, the role of dietary nutrients is not yet fully clarified.

Objective

To assess the potential association between the intake of specific nutrients and the prevalence of myopia in a large, population-based sample of Korean adolescents.

Methods

Data from 18,077 adolescents (average age: 15.05 ± 1.67 years; 51.7% male, 48.3% female) who participated in the 7th Korea National Health and Nutrition Examination Survey (KNHANES VII, 2016) were analyzed. Refractive error was measured using an auto-refractor-keratometer (KR-8800) without cycloplegia. Dietary intake of 14 nutrients was assessed through a 24-h personalized dietary recall method.

Results

The study revealed a myopia prevalence of 87.6% among the adolescents. Multivariable models adjusted for age, gender, BMI, and other confounding factors indicated that higher intakes of carbohydrates, proteins, cholesterol, sodium, and vitamin B2 were associated with an increased risk of myopia. Conversely, higher intake of vitamin C was found to be associated with a decreased risk.

Conclusion

The findings suggested a potential association between dietary nutrient intake and myopia prevalence in Korean adolescents. While the study did not establish a causal link, the differences in nutrient intake between the myopic and non-myopic groups could indicate that diet plays a role in the development or progression of myopia. Further research is warranted to corroborate these findings and explore the underlying mechanisms.

Contribution of Different Food Types to Vitamin A Intake in the Chinese Diet

Vitamin A is a fat-soluble micronutrient that is essential for human health. In this study, the daily vitamin A intake of Chinese residents was evaluated by investigating the vitamin A content of various foods. The results show that the dietary intake of vitamin A in common foods was 460.56 ugRAE/day, which is significantly lower than the recommended dietary reference intake of vitamin A (800 ugRAE/day for adult men and 700 ugRAE/day for adult women). Vegetables contributed the most to daily vitamin A dietary intake, accounting for 54.94% of vitamin A intake (253.03 ugRAE/day), followed by eggs, milk, aquatic products, meat, fruit, legumes, coarse cereals, and potatoes. Therefore, an increase in the vitamin A content of vegetables and the fortification of vegetable oils with vitamin A are effective ways to increase vitamin A intake to meet the recommended dietary guidelines in China. The assessment results support the design of fortified foods.

Benchmarking large language models' performances for myopia care: a comparative analysis of ChatGPT-3.5, ChatGPT-4.0, and Google Bard

BACKGROUND

Large language models (LLMs) are garnering wide interest due to their human-like and contextually relevant responses. However, LLMs' accuracy across specific medical domains has yet been thoroughly evaluated. Myopia is a frequent topic which patients and parents commonly seek information online. Our study evaluated the performance of three LLMs namely ChatGPT-3.5, ChatGPT-4.0, and Google Bard, in delivering accurate responses to common myopia-related queries.

METHODS

We curated thirty-one commonly asked myopia care-related questions, which were categorised into six domains-pathogenesis, risk factors, clinical presentation, diagnosis, treatment and prevention, and prognosis. Each question was posed to the LLMs, and their responses were independently graded by three consultant-level paediatric ophthalmologists on a three-point accuracy scale (poor, borderline, good). A majority consensus approach was used to determine the final rating for each response. 'Good' rated responses were further evaluated for comprehensiveness on a five-point scale. Conversely, 'poor' rated responses were further prompted for self-correction and then re-evaluated for accuracy.

FINDINGS

ChatGPT-4.0 demonstrated superior accuracy, with 80.6% of responses rated as 'good', compared to 61.3% in ChatGPT-3.5 and 54.8% in Google Bard (Pearson's chi-squared test, all p ≤ 0.009). All three LLM-Chatbots showed high mean comprehensiveness scores (Google Bard: 4.35; ChatGPT-4.0: 4.23; ChatGPT-3.5: 4.11, out of a maximum score of 5). All LLM-Chatbots also demonstrated substantial self-correction capabilities: 66.7% (2 in 3) of ChatGPT-4.0's, 40% (2 in 5) of ChatGPT-3.5's, and 60% (3 in 5) of Google Bard's responses improved after self-correction. The LLM-Chatbots performed consistently across domains, except for 'treatment and prevention'. However, ChatGPT-4.0 still performed superiorly in this domain, receiving 70% 'good' ratings, compared to 40% in ChatGPT-3.5 and 45% in Google Bard (Pearson's chi-squared test, all p ≤ 0.001).

INTERPRETATION

Our findings underscore the potential of LLMs, particularly ChatGPT-4.0, for delivering accurate and comprehensive responses to myopia-related queries. Continuous strategies and evaluations to improve LLMs' accuracy remain crucial.

FUNDING

Dr Yih-Chung Tham was supported by the National Medical Research Council of Singapore (NMRC/MOH/HCSAINV21nov-0001).

Myopia Progression in Adults: A Retrospective Analysis

SIGNIFICANCE

Studies on adult myopia progression are limited. This retrospective analysis of a large data set of young adult myopes characterizes myopia progression during adulthood.

PURPOSE

This study aimed to determine the mean annual progression of myopia and to estimate the proportion of progressors in adult myopes.

METHODS

Longitudinal, noncycloplegic subjective refraction data for young adult myopes (spherical equivalent refractive error, -0.5 D or more), age ranging from 18 to 30 years, were retrospectively analyzed. The mean annual progression, as well as the proportion of progressors (at least -0.50 D shift between visits and annualized progression of -0.25 D or more), was estimated.

RESULTS

A total of 354 myopes (230 females [64.7%]), with a mean (standard deviation) age of 22.2 (3.8) years, were considered. The mean (standard deviation) annualized progression was -0.10 (0.21), -0.08 (0.2), and -0.04 (0.21) D in the 18- to 21-year, 22- to 26-year, and 27- to 30-year age groups, respectively ( P = .003). The difference between 18- to 21- and 27- to 30-year age groups was significant ( P = .05), whereas all other pairwise comparisons were not significant. The proportion (95% confidence interval) of progressors in the 18- to 21-, >21- to 26-, and >26- to 30-year age groups was 18.3% (14.9 to 21.7%), 10.9% (7.1 to 14.7%), and 8.8% (4.4 to 13.1%), respectively. The proportion of progressors working or studying in a higher learning/academic environment was 16.2% with an odds ratio (95% confidence interval) for progression of 2.07 (1.15 to 3.74) compared with those in nonacademic environments ( P = .02), with no significant effect of sex or ethnicity.

CONCLUSIONS

This study is consistent with other studies on myopia in young adults, which show that myopia does not progress by substantial amounts throughout the adult years, particularly after the age of 21 years. Although future studies may be challenged by the small rates of change and the small proportion of progressors, further research is needed to understand the implications of adult myopia progression on clinical management.

Interventions recommended for myopia prevention and control among children and adolescents in China: a systematic review

In 2018, a consortium of government bodies in China led by the Ministry of Education released the Comprehensive Plan to Prevent Nearsightedness among Children and Teenagers (CPPNCT), aiming to reduce the incidence of myopia and control myopic progression in China. Recommendations span from home-based to school-based interventions, including time outdoors, physical activity, light exposure, near-work activity, screen time, Chinese eye exercises, diet and sleep. To date, the levels of evidence for this suite of interventions have not been thoroughly investigated. This review has summarised the evidence of the interventions recommended by the CPPNCT in myopia prevention and control. Thus, the following statements are supposed by the evidence: (1) Increasing time outdoors and reducing near-work time are effective in lowering incident myopia in school-aged children. (2) All interventions have a limited effect on myopia progression. Ongoing research may lead to a better understanding of the underlying mechanisms of myopia development, the interaction of different interventions and recommendations, confounding variables and their true effect on myopia prevention, and the identification of those most likely to respond to specific interventions. This field may also benefit from longer-term studies of the various interventions or strategies covered within this review article, to better understand the persistence of treatment effects over time and explore more novel approaches to myopia control.

Prevalence and Risk Factors of Myopia in Young Adults: Review of Findings From the Raine Study

Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15-16 years old. Thus, most studies on myopia have centered on children. Data on the refractive error profile in young adulthood - a time in life when myopia is thought to have stabilized and refractive error is unaffected by age-related pathology such as cataract - are limited. The Raine Study has been following a community-based cohort of young adults representative of the general Western Australia population since their prenatal periods in 1989-1991, with eye examinations performed when participants were 20 and 28 years old. At 20 years old, prevalence of myopia in the cohort was 25.8%. Using long-term trajectory of serum vitamin D levels and conjunctival ultraviolet autofluorescence (CUVAF) area to objectively quantify sun exposure, the Raine Study confirmed a negative relationship between time spent outdoors and myopia prevalence. However, prospective studies are required to determine the amount of CUVAF area or serum vitamin D levels associated with time duration. Combining data from the Raine Study and several other cohorts, Mendelian randomization studies have confirmed a link between myopia and a genetic predisposition toward higher education. Several novel potential associations of myopia or ocular biometry were investigated, including fetal growth trajectory, which was found to be significantly associated with corneal curvature at 20 years. By age 28, myopia prevalence had increased to 33.2%. Between 20 and 28 years old, myopia progressed and axial length elongated, on average, by -0.041D/year and 0.02 mm/year, respectively. Smaller CUVAF area at follow-up, female sex, and parental myopia were significant risk factors for myopia incidence and progression between 20 and 28 years. Given the limited research in young adults, further investigations are warranted to confirm the Raine Study findings, as well as identify novel genetic or environmental factors of myopia incidence and progression in this age group.

Dietary intake and associations with myopia in Singapore children

PURPOSE

To evaluate associations of dietary factors with myopia, spherical equivalent refractive error (SE) and axial length (AL) in children at age 9 from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort.

METHODS

We included 467 multi-ethnic children (933 eyes) who participated in the GUSTO prospective birth cohort and were delivered in two major hospitals in Singapore (2009-2010). At the 9-year visit, we assessed the 6-year incidence of myopia (between ages 3 to 9), cycloplegic SE and AL in children without myopia (SE ≤ -0.5 D in either eye) at the 3-year visit. Using a validated 112-item food frequency questionnaire, parents reported each child's average daily intake of dietary factors (nutrients and food groups) in the past month. Paired eyes were analysed using Generalised Estimating Equations with multivariable logistic or linear regression. Bonferroni corrections were applied, correcting for multiple comparisons between the 13 nutrients (p < 0.004) or 8 food groups (p < 0.006) and each outcome.

RESULTS

In children aged 9 years (51.0% boys; 56.3% Chinese), the 6-year incidence of myopia was 35.5%. Overall, the mean (SD) SE and AL were -0.3 (1.7) D and 23.4 (1.0) mm, respectively. In multivariable regression, macronutrients or micronutrients were not associated with incident myopia (p ≥ 0.004 for all), adjusting for total energy, gender, ethnicity, time outdoors, near-work and the number of myopic parents (additionally child's height for outcome AL). Similarly, all food groups (including refined grains, sugar-sweetened beverages, protein foods, fruits and vegetables) were not associated with incident myopia (p ≥ 0.006 for all). Additionally, none of the nutrients (p ≥ 0.004 for all) or food groups (p ≥ 0.006 for all) were associated with SE or AL.

CONCLUSIONS

Our study findings of no significant association between specific nutrients or food groups and incident myopia or SE or AL suggest that diet may not be associated with myopia in children aged 9 years. Well-conducted prospective studies in other populations may clarify the association.

Influence of the interaction between parental myopia and poor eye habits when reading and writing and poor reading posture on prevalence of myopia in school students in Urumqi, China

Background

To evaluate the prevalence of myopia in school students in Urumqi, China, and explore the influence of the interaction between parental myopia and poor reading and writing habits on myopia to identify the at-risk population and provide evidence to help school students avoid developing myopia.

Methods

A cross-sectional survey was conducted with 6,883 school students aged 7–20 years in Urumqi in December 2019. The Standard Eye Chart and mydriatic optometry were used to determine whether students had myopia. Falconer’s method was used to calculate the heritability of parental myopia. Multivariate unconditional logistic regression models were used to analyze the risk factors for myopia and the additive and multiplicative interaction of parental myopia and poor reading and writing habits.

Results

After standardizing the age of the 6,883 students, the overall prevalence rate of myopia was 47.50 %. The heritability of parental myopia was 66.57 % for boys, 67.82 % for girls, 65.02 % for the Han group, and 52.71 % for other ethnicities. There were additive interactions between parental myopia and poor reading and writing habits; among them, parental myopia and poor eye habits when reading and writing (the distance between the eyes and book is less than 30 cm when reading and writing, fingers block the sight of one eye while holding the pen, and leaning one’s body when reading and writing; habit 1) increased the risk of myopia by 10.99 times (odds ratio [OR] = 10.99, 95 % confidence interval [CI] = 8.33–14.68), parental myopia and poor reading posture (reading while lying down, walking, or in the car; habit 2) increased the risk of myopia by 5.92 times (OR = 5.92, 95 % CI = 4.84–7.27). There was no multiplicative interaction between parental myopia and habit 1 or habit 2 (OR = 0.69, 95 % CI = 0.44–1.08; OR = 0.89, 95 % CI = 0.66–1.21, respectively).

Conclusion

The prevalence of myopia among students in Urumqi, Xinjiang is relatively high. The risk of developing myopia is affected by parental myopia and poor reading and writing habits. In addition, parental myopia amplifies the harm caused by poor reading and writing habits, thereby increasing the risk of myopia. Students with parents who have myopia should be targeted during myopia prevention efforts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02058-3.