Relation between near work and myopia progression in student population

Myopia and Near Work: A Systematic Review and Meta-Analysis

BACKGROUND

Myopia is a global public health problem affecting quality of life and work productivity. Data is scarce regarding the effects of near work on myopia. Providing a larger meta-analysis with life-long perspective, including adults and occupational exposure seemed needed.

METHODS

We searched PubMed, Cochrane Library, Embase and Science Direct for studies reporting myopia prevalence in near work. Myopia was defined as a mean spherical equivalent ≤ -0.50 diopter. We performed a meta-analysis using random-effects model on myopia prevalence, myopia progression per year, and odds ratio (OR) of myopia in near work, completed by subgroup analyses and meta-regressions on patients' characteristics, type of work in adults, geographic zones, time and characteristics of near work.

RESULTS

We included 78 studies, representing a total of 254,037 participants, aged from 6 to 39 years. The global prevalence of myopia in near work was 35% (95% CI: 30 to 41%), with a prevalence of 31% (95% CI: 26 to 37%) in children and 46% (95% CI: 30 to 62%) in adults. Myopia progression was -0.39 diopters per year (-0.53 to -0.24 D/year), ranging from -0.44 (-0.57 to -0.31) in children to -0.25 D/year (-0.56 to 0.06) in adults. The odds of myopia in workers exposed vs. non-exposed to near work were increased by 26% (18 to 34%), by 31% (21 to 42%) in children and 21% (6 to 35%) in adults. Prevalence of myopia was higher in adults compared to children (Coefficient 0.15, 95% CI: 0.03 to 0.27).

CONCLUSIONS

Near work conditions, including occupational exposure in adults, could be associated with myopia. Targeted prevention should be implemented in the workplace.

Online survey to assess computer vision syndrome in children due to excessive screen exposure during the COVID 19 pandemic lockdown

Background

During the COVID-19 pandemic lockdown, the normal daily routine activities of children were restricted as a result of the need to stay indoors. Consequently, children were forced to attend online classes provided by their educational institutions at their homes. Due to the subsequent increased screen exposure, children have started complaining of blurred vision, headache, and symptoms related to computer vision syndrome (CVS), predisposing them to myopia.

Objective

To determine the prevalence of CVS symptoms, such as blurring of vision, headache, and watery eyes in children, due to increased screen time during the lockdown period of the COVID-19 pandemic.

Methods

This was a non-randomized, questionnaire-based study conducted at the ophthalmology department of a tertiary care pediatric hospital. The participants were parents of children aged between 6 and 16 years attending regular school. Enrolled parents were interviewed through a Google Form after completing the online consent in English. Eligible participants were recruited by a circulation of this form through multiple groups on social media, namely, WhatsApp and email.

Results

A total of 145 parents participated in the study. The children were classified according to the duration of exposure to digital devices ranging from less than 2 h to less than 6 h daily. There was a significant association between the increase in the number of activities and the development of CVS symptoms in children (r = 0.15; P = 0.036).

Conclusion

COVID-19 lockdown has largely affected the lifestyle of school-going children by significantly decreasing their outdoor activities and increased online exposure to screen, thus predisposing them to myopia, ocular ill health, and increased dry eye symptoms. Increased exposure to online screen was detected during this lockdown period of the COVID-19 pandemic; this strongly supports the recommendation to decrease the number of hours of online screen exposure and encourages students to regularly get engaged in outdoor activities.

The G allele of the IGF1 rs2162679 SNP is a potential protective factor for any myopia: Updated systematic review and meta-analysis

Background

The insulin-like growth factor 1 (IGF1) gene is located within the myopia-associated MYP3 interval, which suggests it may play an important role in the progression of myopia. However, the association between IGF1 SNPs and any myopia is rarely reported.

Methods

A comprehensive literature search was conducted on studies published up to July 22, 2021 in PubMed, EMBASE, CBM, COCHRANE, CNKI, WANFANG and VIP databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for single-nucleotide polymorphisms (SNPs) that have been evaluated in at least three studies.

Results

Nine studies involving 4596 subjects with any myopia and 4950 controls examined 25 SNPs in IGF1 gene, among which seven SNPs were included in this meta-analysis. Significant associations were not found in any genetic models between rs6214, rs12423791, rs5742632, rs10860862, rs5742629 and any myopia. Rs2162679 was suggestively associated with any myopia in the codominant model (GA vs. AA: OR = 0.87, 95% CI: 0.76–1.00) and the dominant model (GG+GA vs. AA: OR = 0.88, 95% CI = 0.78–1.00).

Conclusion

Meta-analysis of updated data reveals that the G allele of the IGF1 rs2162679 SNP is a potential protective factor for any myopia, which is worth further researches.

A systematic review of near work and myopia: measurement, relationships, mechanisms and clinical corollaries

After decades of investigation, the role of near work in myopia remains unresolved, with some studies reporting no relationship and others finding the opposite. This systematic review is intended to summarize classic and recent literature investigating near work and the onset and progression of myopia, potential mechanisms and pertinent clinical recommendations. The impact of electronic device use is considered. PubMed and Medline were used to find peer-reviewed cross-sectional and longitudinal studies related to near work and myopia from 1980 to July 2020 using the PRISMA checklist. Studies were chosen using the Joanna Briggs Institute checklist, with a focus on studies with a sample size greater than 50. Studies were independently evaluated; conclusions were drawn per these evaluations. Numerous cross-sectional studies found increased odds ratio of myopia with increased near work. While early longitudinal studies failed to find this relationship, more recent longitudinal studies have found a relationship between myopia and near work. Rather than daily duration of near work, interest has increased regarding absolute working distance and duration of continuous near viewing. Several reports have found that shorter working distances (<30 cm) and continuous near-work activity (>30 min) are risk factors for myopia onset and progression. Novel objective continuously measuring rangefinding devices have been developed to better address these questions. The literature is conflicting, likely due to the subjective and variable nature in which near work has been quantified and a paucity of longitudinal studies. We conclude that more precise objective measures of near viewing behaviour are necessary to make definitive conclusions regarding the relationship between myopia and near work. Focus should shift to utilizing objective and continuously measuring instruments to quantify near-work behaviours in children, followed longitudinally, to understand the complex factors related to near work. A better understanding of the roles of absolute working distance, temporal properties, viewing breaks and electronic device use on myopia development and progression will aid in the development of evidence-based clinical recommendations for behavioural modifications to prevent and slow myopia.

Peripheral refraction of myopic eyes with spectacle lenses correction and lens free emmetropes during accommodation

PURPOSE

To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m (0.50 D) to 0.20 m (5.00 D) in terms of sphere, astigmatism, and spherical equivalent refraction.

METHODS

Refraction was measured at the center, 20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field, binocular, infrared autorefractor (Grand Seiko WAM-5500, Hiroshima, Japan). Fixation target was a Maltese cross set at 2.00, 0.50, 0.33 and 0.20 m from the corneal plane. Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.

RESULTS

Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance. Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group. This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.

CONCLUSION

Accommodation to very near targets (up to 0.20 m) makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes. A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.

Lifestyle modification in school-going children before and after COVID-19 lockdown

Purpose

To evaluate the impact of COVID-19 lockdown restrictions on lifestyle of school-going children.

Methods

This was a questionnaire-based prospective study of 1237 school children aged 9-14 years enrolled from various private and government schools across Delhi in October-December 2020. These children were being followed-up over the previous 2 years (before pandemic) with details of their lifestyle like near/outdoor/reading activities using a questionnaire as a part of another study. The data during the COVID-19 lockdown was collected by telephonic interview. This was compared to similar information collected from this cohort in the pre-Covid period in 2019 when the students had a regular physical school curriculum.

Results

A significant decline was noted in time spent on outdoor activity (from 8.5 hours/week in pre-COVID-19 time to 1.6 hours/week during COVID-19 lockdown; P < 0.001) and doing homework offline (from 15.3 hour/week to 14 hours/week; P < 0.001). A significant increase was noted in screen time spent on digital devices (from 6.2 hours/week to 19.8 hours/week; P<0.001), and watching television (from 12.2 hours/week to 13.4 hours/week; P < 0.001). The rise in the digital on-screen time was significantly more in boys (P < 0.001) and in students from private schools (P < 0.001). The rise in the duration of watching television was significantly more in girls than boys (P < 0.05).

Conclusion

COVID-19 lockdown has markedly impacted the lifestyle of school children by significantly decreasing the outdoor activity and increasing the screen time, thereby pre-disposing them to ocular ill-health and myopia. This necessitates the adoption of guidelines for promoting healthy digital habits in children.

The Relationship Between Screen and Outdoor Time With Rates of Myopia in Spanish Children

Background: Nowadays, digital devices have become usual in children's lives around the world. Five percent of the children between 5 and 7 years old have their own smartphone and forty-two percent of them have their own tablet. This fact has produced a change in their lifestyle that can imply some risks, threats and/or opportunities. The light emitted by digital devices' screens could involve, among others, possible risks to children's vision. Methods: This study shows a detailed analysis of the vision of 7,497 children between 5 and 7 years old carried out in the "Annual school campaign for children's visual health" in Spain during the years 2016, 2017, and 2019. The study connects the results in the visual screening with children's lifestyle, taking into account both, the number of hours per day that they use all digital devices and the daily time of outdoor exposure. Results: The study shows that children with myopia have more screen time use and shorter outdoor activity time when compared to those without myopia (p < 0.01). Conclusions: Myopia in children is a public health problem and requires healthy lifestyle interventions at individual as well as at community level.

An effectiveness study of a wearable device (Clouclip) intervention in unhealthy visual behaviors among school-age children: A pilot study

INTRODUCTION

The study aimed to determine the effectiveness of an intervention for unhealthy visual behaviors of school-age children using a wearable device (Clouclip).

METHOD

The design was a self-controlled prospective study. Clouclip, with the vibration alert disabled, was first applied to measure baseline near-work behaviors in the first week. The vibration alert was then enabled to signal unhealthy visual behaviors (near-work distance < 30 cm and >5 seconds, or near-work distance <60 cm for >45 minutes) for 3 weeks. Near-work behaviors were measured again at the first week and the first month after intervention, respectively. The changes in behaviors between the baseline and the first week and the first month after intervention were analyzed.

RESULTS

Sixty-seven subjects were eligible for this experiment (the mean age 10.45 ± 0.50 years, 34 boys). Children who logged sufficient wearing time (12.30 ± 0.18 hours on weekdays and 12.16 ± 0.23 hours on weekends) were included for analysis. The average daily near-work distance was significantly increased after the vibration intervention. The time ratio of near-work activity <30 cm to the total <60 cm and the frequency of continuous near-work (distance <60 cm and continuous time >30 minutes) were significantly decreased after the intervention. Although some of the effects were reversed with time following the intervention, some were observed to be maintained until the end of the observation period, and the improvement of the behaviors was more prominent in children who had a shorter near-work distance (<30 cm) at baseline.

CONCLUSIONS

In conclusion, Clouclip can significantly modify near-work behaviors in school-age children and it can last a certain period of time. If these behaviors are causes of myopia development and progression, Clouclip might provide a strategy for managing myopia.

Objective User Visual Experience Evaluation When Working with Virtual Pixel-Based 3D System and Real Voxel-Based 3D System

Volumetric display shows promising implications for healthcare related applications as an innovative technology that creates real three-dimensional (3D) image by illuminating points in three-dimensional space to generate volumetric images without image separation. We used eccentric photorefractometry to objectively study ocular performance in a practical environment by evaluating near work-induced refraction shift, accommodative microfluctuations, and pupil size for 38 young adults after viewing anaglyph, and volumetric 3D content for prolonged time. The results of our study demonstrate that participants who performed relative depth estimation task on volumetric 3D content were less likely to experience task-induced myopic refraction shift. For both 3D content types, we observed pupil constriction, that is possibly related to visual fatigue. For anaglyph 3D pupil constriction, onset was observed significantly sooner, compared to volumetric 3D. Overall, sustained work with 3D content, and small disparities or the fully eliminated possibility of accommodation-vergence conflict, not only minimizes near work-induced myopic shift, but also provide beneficial accommodation relaxation that was demonstrated in this study as hypermetropic shift for nearly half of participants.

Ethnic disparity in prevalence and associated risk factors of myopia in adolescents

BACKGROUND/PURPOSE

To examine ethnic disparity in prevalence and associated factors of myopia in adolescents using the Unites States National Health and Nutrition Examination Survey (NHANES) dataset.

METHODS

Participants who were aged 12-19 years were included from NHANES (1999-2008). Logistic regression analyses were applied to identify risk factors associated with myopia after stratification by race.

RESULTS

A total of 9,960 participants were included in the prevalence analysis, and 6,571 in the risk factor analysis. Other race (excluded Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black) participants had the highest frequency of myopia (42.77%). Multivariate analyses of the whole population suggested that the odds of myopia were significantly lower in participants with household smokers (odds ratio [OR] = 0.79, 95% confidence interval [CI]: 0.66-0.97), and significantly greater in Mexican American race (OR = 1.28, 95% CI: 1.01-1.62), other Hispanic (OR = 1.79, 95% CI: 1.10-2.92) and in participants with senior high school graduate education (OR = 1.79, 95% CI: 1.01-3.18), watched 2 hours of television daily (OR = 1.27, 95% CI: 1.02-1.59), used the computer for 1 hour daily (OR = 1.276, 95% CI: 1.02-1.57). When examined by race/ethnicity, 1 hour of computer use increased the odds of myopia in the non-Hispanic White group, in Mexican Americans a higher family poverty income ratio and 2 hours of television time was associated with myopia, and in the Other Hispanic group, a higher family poverty income ratio was associated with myopia, while males and those with a higher sugar had a lower risk of myopia.

CONCLUSION

Risk factors for myopia vary with race/ethnicity.

Ocular surface health in Shanghai University students: a cross-sectional study

BACKGROUND

Our study aimed to investigate the ocular surface health of Shanghai University students.

METHODS

This is a cross-sectional study carried out among freshmen and sophomores on the main campus of Shanghai University. Questionnaires including the widely-used ocular surface disease index (OSDI) and the Zung Self-rating Anxiety Scale (SAS) were completed first, and then ocular examinations were conducted regarding height & weight, blood pressure and heart rate, optometry, intraocular pressure exam, vision and subjective refraction, Aladdin, Macular pigment density measurement, tear test, anterior segment examination, fundus photography, ophthalmologist check, TOPCON OCT check, and Collin's fundus blood test.

RESULTS

Totally 901 students were involved in our five-day study. The prevalence of myopia was 92% (the spherical equivalent refraction (SER) < - 0.50 D), and that of high myopia was 23% (SER < - 6.0D). The prevalence of dry eye disease (DED) was 10%. The corneal epithelial loss rate (corneal fluorescein staining > 1) was 10%, and corneal sensation decline rate (≤ 30 mm) was 12%. 4.5% of subjects (n = 40) had moderate or severe anxiety, 78% were mild and a small portion (17.5%) didn't have anxiety at all. No statistical significant association was found between anxiety with DED, fluorescein staining or with corneal sensation (all p > 0.05). However, subjects with DED had more symptoms of anxiety. Results also showed that students who kept eye strain for a long time were more inclined to have DED (12.5%: 6.9%, p = 0.0407, 95% CI); those who watched mobile phones and/or computers for over eight hours daily were more vulnerable to DED and fluorescein staining than others (14.1%: 8.6%, p = 0.0129; 13.0%: 8.3%, p = 0.0233, 95% CI).

CONCLUSIONS

Keeping eye strain or near work for a long time is associated with DED, while students with DED tend to encounter anxiety symptoms. The prevalence of myopia in Chinese university students is still high. We consider it necessary to provide education to university students about the good eye-using habits, and to diagnose anxiety for student patients with DED.

Myopia Progression Risk: Seasonal and Lifestyle Variations in Axial Length Growth in Czech Children

The growth in the prevalence of myopia leads to the growth of socioeconomic stress in society. It is important to detect any potential risk factors leading to myopia onset and progression. Among the potential risk factors, the lack of natural daylight exposure and the lack of the physical activity together with excess of near-work activities in children are the most prevalent. In the study, the axial length growth depending on the season and the type of behaviour was measured. The assessment was performed in 12-year-old children, 398 eyes of whom were included and measured during the winter and summer period. The children were categorized by the amount of time spent on near-work, physical, and outdoor activity. Results. Statistically significantly higher (p < 0.0001) axial length growth was observed during the winter period. Statistically significantly (p < 0.0001) more frequently, the eyeball growth has been proved during the winter season. According to the way of spending leisure time, no statistically significant difference was reported within the individual subgroups in the development of the eyeball length during the observed period. However, statistically significant differences were ascertained in the eyeball initial length within various groups. Conclusion. The lack of daylight exposure may lead to myopia progression.

Real-Time Non-Intrusive Assessment of Viewing Distance during Computer Use

PURPOSE

To develop and test the sensitivity of an ultrasound-based sensor to assess the viewing distance of visual display terminals operators in real-time conditions.

METHODS

A modified ultrasound sensor was attached to a computer display to assess viewing distance in real time. Sensor functionality was tested on a sample of 20 healthy participants while they conducted four 10-minute randomly presented typical computer tasks (a match-three puzzle game, a video documentary, a task requiring participants to complete a series of sentences, and a predefined internet search).

RESULTS

The ultrasound sensor offered good measurement repeatability. Game, text completion, and web search tasks were conducted at shorter viewing distances (54.4 cm [95% CI 51.3-57.5 cm], 54.5 cm [95% CI 51.1-58.0 cm], and 54.5 cm [95% CI 51.4-57.7 cm], respectively) than the video task (62.3 cm [95% CI 58.9-65.7 cm]). Statistically significant differences were found between the video task and the other three tasks (all p < 0.05). Range of viewing distances (from 22 to 27 cm) was similar for all tasks (F = 0.996; p = 0.413).

CONCLUSIONS

Real-time assessment of the viewing distance of computer users with a non-intrusive ultrasonic device disclosed a task-dependent pattern.