Refractive Error and the Risk of Age-Related Macular Degeneration in the South Korean Population

Application of mendelian randomization in ocular diseases: a review

Ocular disorders can significantly lower patients' quality of life and impose an economic burden on families and society. However, for the majority of these diseases, their prevalence and mechanisms are yet unknown, making prevention, management, and therapy challenging. Although connections between exposure factors and diseases can be drawn through observational research, it is challenging to rule out the interference of confounding variables and reverse causation. Mendelian Randomization (MR), a method of research that combines genetics and epidemiology, has its advantage to solve this problem and thus has been extensively utilized in the etiological study of ophthalmic diseases. This paper reviews the implementation of MR in the research of ocular diseases and provides approaches for the investigation of related mechanisms as well as the intervention strategies.

Causal associations of refractive error and early age-related macular degeneration: A Mendelian randomization study

This study aims to determine the risk associated with early age-related macular degeneration (AMD) due to refractive errors (RE) using an analysis of genome-wide association study (GWAS) data through the two-sample Mendelian randomization approach. Single-nucleotide polymorphisms (SNPs) linked to refractive errors (RE) were obtained from numerous GWAS studies involving individuals of European descent. The data for early AMD was obtained from a diverse, multiethnic GWAS meta-analysis that included 105,248 participants (14,034 cases and 91,214 controls). The primary outcome measure focused on the rise in early AMD risk corresponding to a 1-diopter alteration in spherical power and cylindrical power. In the main Mendelian randomization analysis, inverse-variance weighting (IVW) methods were applied for the evaluation. Mendelian Randomization (MR) study revealed a substantial impact of refractive error (RE) on early AMD risk, with a 1-diopter increase in hypermetropia being related to a 1.16 odds ratio (OR) for a greater risk of early AMD (95% CI, 1.10-1.23; P < 0.01). This conclusion was further supported by four supplementary approaches, namely, Weighted mode, Weighted-median, Simple mode, and MR-Egger. The results suggest a heightened risk of early AMD correlated with hyperopia, necessitating further research to thoroughly elucidate this potential causal relationship.

Myopia intervention and ultraviolet radiation related eye diseases: A narrative literature review

There has been an increased understanding of the protective effect of two or more hours in high lux light on the development and progression of myopia. The aim of myopia management is to reduce the incidence of high myopia and sight-threatening myopic complications. Equally important are the sight-threatening complications of ultraviolet radiation (UVR) on the eye and adnexal structures. This review will analyze the literature for both these epidemics to help guide public health policy. Whilst increasing childhood high lux light exposure is important, consideration of a holistic eye health policy should ensure that UV eye diseases are also prevented. The advent of ultraviolet (UV) fluorescence photography has increased our understanding that significant UV eye damage occurs in childhood, with 81% of children aged 12-15 years having signs of UV eye damage. Hence, the need to reduce myopia and protect from UV-related eye diseases needs simultaneous consideration. Advocating for eye protection is important, particularly as the natural squint reflex is disabled with dark sunglasses lenses. The pathways UV reaches the eye need to be considered and addressed to ensure that sunglasses offer optimum UV eye protection. The design of protective sunglasses that simultaneously allow high lux light exposure and protect from UVR is critical in combating both these epidemics.

Interaction between parental myopia and children lifestyle on the incidence of myopia among children aged 6-18 years: a cross-sectional study in Tianjin, China

OBJECTIVES

This study aimed to explore the influence of the interaction between parental myopia and lifestyle on myopia among school-age children.

DESIGN

Cross-sectional study.

SETTING

This study used data from the Tianjin Child and Adolescent Research of Eye between August and October 2022.

PARTICIPANTS

A total of 49 035 participants between 6 and 18 years of age were eligible for this study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the interaction between eye-healthy lifestyle and parental myopia on myopia. Parental myopia and eye-healthy lifestyle were ascertained by a Child and Adolescent Behavior Questionnaire. The lifestyle risk score (LRS) of eye health was calculated based on beta-coefficient in the backward regression model. The interaction between LRS and parental myopia was analysed by multivariate logistic regression. The predictive value of different predicted models was estimated using receiver operating characteristic curves. Multiple linear regression was used to evaluate the associations of lifestyle risk factors and parental myopia with spherical equivalent refraction, which were defined as the secondary outcomes.

RESULTS

A total of 31 839 participants aged 6-18 years were included, and the myopia prevalence was 55.46%. Eye-healthy lifestyle and parental myopia were significantly associated with myopia, as was interaction. The predictive value for LRS & parental myopia was 0.714 (95% CI: 0.709 to 0.720), which was higher than LRS (0.693, 95% CI: 0.687 to 0.699) and parental myopia (0.710, 95% CI: 0.704 to 0.716) separately.

CONCLUSIONS

High-risk lifestyles of myopia and parental myopia were significantly associated with a higher risk of myopia, and the combination had the strongest effect. For children, lifestyle adjustment should be prioritised in preventing myopia, especially for those with parental myopia.

Analysis of the reports of low-concentration atropine in controlling myopia in children

PURPOSE

To evaluate the efficacy of 0.01% atropine to slow the progression of myopia in children.

METHODS

We searched PubMed, Embase, ClinicalTrials.gov, CNKI, Cqvip and Wan fang databases from inception to January 2022, including RCTs (randomized controlled trials) and non-RCTs (non-randomized controlled trials). The search strategy was 'myopia' OR 'refractive error' and 'atropine.' Two researchers independently reviewed the articles, and stata12.0 was used for meta-analysis. The Jadad score was used to assess the quality of RCT, and the Newcastle-Ottawa scale was used for non-RCTs.

RESULTS

Five RCTs and two non-RCTs (1 prospective non-randomized controlled study, 1 retrospective cohort study) were identified (including 1000 eyes). Results of the meta-analysis showed statistical heterogeneity among the 7 included studies (P=0. 026, I2 =47.1%). According to different durations of atropine use - 4 months, 6 months and greater than 8 months, subgroup analysis results showed that the axial elongation of all experimental groups relative to control groups were respectively -0.03mm (95% [CI], (confidence interval), -0.07 to 0.01), -0.07mm (95% [CI], -0.10 to -0.05), -0.09mm (95% [CI], -0.12 to -0.06). Each P was greater than 0.05, which indicated that there is little heterogeneity among the subgroups.

CONCLUSIONS

In this meta-analysis of the short-term efficacy of atropine in myopia patients, it was found that there was little heterogeneity when grouped by usage time. It is suggested that the use of atropine in the treatment of myopia is not only related to its concentration but also related to the duration of use.

Obesity and high myopia in children and adolescents: Korea National Health and Nutrition Examination Survey

Purpose

The prevalence of both obesity and myopia are increasing in Korean children and adolescents. The purpose of this study is to examine the impact of obesity on the prevalence of myopia in Korean children and adolescents.

Methods

This study used the data of a nationally representative cross-sectional survey, the Korea National Health and Nutrition Examination Survey (KNHANES) VII conducted from 2016 to 2018. Of the 1237 children and adolescents aged 5–18 years who participated in the KNHANES VII and underwent ophthalmologic examinations for the survey, 1114 were selected for review, excluding those whose data on refractive error, family history of myopia, or waist circumference were missing. Body mass index (BMI) was classified into four groups: underweight (< 5th percentile), normal weight (≥ 5th percentile, < 85th percentile), overweight (≥ 85th percentile, < 95th percentile), and obese (≥ 95th percentile). Myopia was defined by the level of refractive error ≤ -0.5 diopters (D) and classified as mild (≤ -0.5 D, > -3.0 D), moderate (≤ -3.0 D, > -6.0 D), or high (≤ -6.0 D) myopia. The relationship between BMI and myopia was analyzed using complex sample logistic regression. Age and family history were corrected followed by an analysis of the odds ratios.

Results

Compared to those with normal weights (controls), being underweight, overweight, or obese showed no significant odds of developing mild and moderate myopia. Conversely, when compared with that of controls, the odds ratio of developing high myopia in the underweight, overweight, and obese groups was 0.77 (95% CI, 0.22–2.65), 1.37 (95% CI, 0.51–3.66), and 3.77 (95% CI, 1.98–7.16), respectively. Furthermore, in a separate analysis by sex and BMI, the odds ratio of developing high myopia was 2.84 (95% CI, 1.10–7.35) in boys with obesity and 4.23 (95% CI,1.19–15.09) and 5.04 (95% CI,1.77–14.34) in overweight and obese girls, respectively.

Conclusions

An association exists between obesity in childhood and adolescence and high myopia. Being overweight in girls was also found to be associated with high myopia. Thus, efforts to maintain a healthy weight during childhood and adolescence are of great importance.

Recent Epidemiology Study Data of Myopia

Myopia, a pandemic refractive error, is affecting more and more people. The progression of myopia could cause numerously serious complications, even leading to blindness. This review summarizes the epidemiological studies on myopia after 2018 and analyzes the risk factors associated with myopia. The prevalence of myopia varies in different regions, age, and observation time. East Asia has been gripped by an unprecedented rise in myopia, and other parts of the world have also seen an increase. The prevalence of myopia in children continues to rise and aggravates with age. The prevalence of high myopia has also increased along with myopia. Racial dependence and family aggregation can be seen frequently in myopia patients. Increased outdoor activities are proven to be protective factors for myopia, as near-distance work and higher education levels affect in the opposite. The impact of gender or urbanization on myopia is controversial. The relationship between nutrition, digital screens, Kawasaki disease, pregnant women smoking during pregnancy, and myopia is still not clear for lack of sufficient evidence. Understanding the various factors that affect myopia helps to clarify the mechanism of myopia formation and also to formulate reasonable prevention and control measures of myopia to protect people's health, especially for adolescents.

Age- and sex-based evaluation of the association between refractive error and age-related macular degeneration in the Korean population

PURPOSE

The aim of this study was to investigate the association between refractive error and prevalence of age-related macular degeneration (AMD) in Korean adults, based on the sex and age group.

METHODS

This was a nationwide population-based cross-sectional study that included 17,676 subjects aged over 40 years who participated in the 2008-2012 Korean National Health and Nutrition Examination Survey. Digital fundus images (45°) were obtained for both eyes under physiologic mydriasis and were graded using the international classification and grading system for age-related macular degeneration. The spherical equivalents of refractive errors were calculated in diopters using auto-refraction data.

RESULTS

After adjustment for potential confounders, myopia was associated with lower risk of any age-related macular degeneration [odds ratio (OR), 0.74; 95% Confidence Interval (CI), 0.61-0.91]. In particular, myopia was significantly associated with lower odds of age-related macular degeneration in female participants (any AMD: OR, 0.71; 95% CI, 0.54-0.93; early AMD: OR, 0.70; 95% CI, 0.53-0.93) and in participants younger than 50 years (any AMD: OR, 0.46; 95% CI, 0.24-0.90; early AMD: OR, 0.47; 95% CI, 0.24-0.93). There was no significant association between myopia and age-related macular degeneration in male participants and in participants older than 50 years.

CONCLUSIONS

In the Korean adult population, myopia was associated with significantly lower odds of any type of early age-related macular degeneration, particularly in females and in younger age groups.

Genetic pleiotropy between age-related macular degeneration and 16 complex diseases and traits

BACKGROUND

Age-related macular degeneration (AMD) is a common condition of vision loss with disease development strongly influenced by environmental and genetic factors. Recently, 34 loci were associated with AMD at genome-wide significance. So far, little is known about a genetic overlap between AMD and other complex diseases or disease-relevant traits.

METHODS

For each of 60 complex diseases/traits with publicly available genome-wide significant association data, the lead genetic variant per independent locus was extracted and a genetic score was calculated for each disease/trait as the weighted sum of risk alleles. The association with AMD was estimated based on 16,144 AMD cases and 17,832 controls using logistic regression.

RESULTS

Of the respective disease/trait variance, the 60 genetic scores explained on average 4.8% (0.27-20.69%) and 16 of them were found to be significantly associated with AMD (Q-values < 0.01, p values from < 1.0 × 10^-16 to 1.9 × 10^-3). Notably, an increased risk for AMD was associated with reduced risk for cardiovascular diseases, increased risk for autoimmune diseases, higher HDL and lower LDL levels in serum, lower bone-mineral density as well as an increased risk for skin cancer. By restricting the analysis to 1824 variants initially used to compute the 60 genetic scores, we identified 28 novel AMD risk variants (Q-values < 0.01, p values from 1.1 × 10^-7 to 3.0 × 10^-4), known to be involved in cardiovascular disorders, lipid metabolism, autoimmune diseases, anthropomorphic traits, ocular disorders, and neurological diseases. The latter variants represent 20 novel AMD-associated, pleiotropic loci. Genes in the novel loci reinforce previous findings strongly implicating the complement system in AMD pathogenesis.

CONCLUSIONS

We demonstrate a substantial overlap of the genetics of several complex diseases/traits with AMD and provide statistically significant evidence for an additional 20 loci associated with AMD. This highlights the possibility that so far unrelated pathologies may have disease pathways in common.

Accuracy of Intraocular Lens Power Calculation Formulas for Highly Myopic Eyes

Purpose. To evaluate and compare the accuracy of different intraocular lens (IOL) power calculation formulas for eyes with an axial length (AL) greater than 26.00 mm. Methods. This study reviewed 407 eyes of 219 patients with AL longer than 26.0 mm. The refractive prediction errors of IOL power calculation formulas (SRK/T, Haigis, Holladay, Hoffer Q, and Barrett Universal II) using User Group for Laser Interference Biometry (ULIB) constants were evaluated and compared. Results. One hundred seventy-one eyes were enrolled. The Barrett Universal II formula had the lowest mean absolute error (MAE) and SRK/T and Haigis had similar MAE, and the statistical highest MAE were seen with the Holladay and Hoffer Q formulas. The interquartile range of the Barrett Universal II formula was also the lowest among all the formulas. The Barrett Universal II formulas yielded the highest percentage of eyes within ±1.0 D and ±0.5 D of the target refraction in this study (97.24% and 79.56%, resp.). Conclusions. Barrett Universal II formula produced the lowest predictive error and the least variable predictive error compared with the SRK/T, Haigis, Holladay, and Hoffer Q formulas. For high myopic eyes, the Barrett Universal II formula may be a more suitable choice.