Intraocular Pressure and Myopia Progression, Axial Length Elongation in Rural Chinese Children.

SIGNIFICANCE: This study reported the relationship between intraocular pressure (IOP) and myopia progression, which helps to understand more comprehensively whether IOP can be an important reference factor to intervene in the progression of myopia. PURPOSE: This study aimed to investigate the association between IOP and myopia progression as well as axial length elongation in rural Chinese children. METHODS: A total of 598 (598 of 878 [68.1%]) children (6 to 17 years) from the baseline Handan Offspring Myopia Study who completed a 3.5-year follow-up vision examination were included. Ocular examinations at both visits included cycloplegic autorefraction, IOP, and axial length measurements. RESULTS: Children with myopia had the highest baseline IOP of the three refractive groups (14.13 ± 1.31, 13.78 ± 1.71, and 13.59 ± 1.64 mmHg in myopes, emmetropes, and hyperopes, respectively, P = .002). However, IOPs showed no significant difference between eyes with or without newly developed myopia (13.63 ± 1.68 vs. 13.89 ± 1.68, P = .16), with or without faster myopia progression (13.75 ± 1.61 vs. 13.86 ± 1.63, P = .46), or with axial length elongation (13.80 ± 1.61 vs. 13.76 ± 1.64, P = .80). The multivariate regression analysis demonstrated that neither baseline refractive error ( ß = -0.082, P = .13) nor baseline axial length ( ß = -0.156, P = .08) was associated with baseline IOP. CONCLUSIONS: Myopic eyes have slightly higher IOP compared with emmetropic and hyperopic eyes, although it was not clinically significant. However, IOP was not found to be associated with either myopia progression or axial length elongation in this cohort sample of rural Chinese children.

A comparative study of the prevalence of myopia and behavioral changes in primary school students.

OBJECTIVE: To analyze the changes in the prevalence of myopia and its relation to ocular biological parameters, and behaviors among primary school students in China, and understand the prevention and control of myopia. METHODS: Cross-sectional surveys were performed on 7-9-year-old children in the yrs. 2012 and 2019. In addition, spherical equivalent refraction (SER), axial length (AL), and AL/corneal radius ratio (AL/CR ratio) were collected without cycloplegia. Participants completed detailed questionnaires on behavior related to myopia. RESULTS: Data was collected on 623 children (8.02 ± 0.57 years old) in 2012 and 536 students in 2019 (8.09 ± 0.65 years old). The prevalence of myopia was 37.7% in 2012 and 39.9% in 2019. The SER was -0.25 (0.92) D in 2012 and -0.25 (1.25) in 2019. There was no statistical difference in the prevalence of myopia and SER over the 7 years (all P > 0.05). In 2019, the prevalence of myopia among girls demonstrated an increasing trend (33.8% vs. 37.8%), but there was no statistical difference (P > 0.05). The mean AL and AL/CR ratio of boys were decreasing (all P < 0.05). The proportion of children reading more than 2 h and using digital devices for more than 2 h per day after their classes in the 2019 group both decreased (all P < 0.05). However, the proportion of activities performed outdoors for more than 2 h./day decreased significantly (P = 0.001). CONCLUSION: Compared with 2012, the prevalence of myopia in primary school students in 2019 was under control, which may be related to the improvement of children's near-work behavior, but there was the problem of insufficient outdoor activity time. In terms of ocular biological parameters, the risk of myopia for boys in 2019 was lower.

Elementary school comprehensive intervention and myopia development: the Wenzhou Epidemiology of Refraction Error Study.

AIM: To investigate the effects of school-based comprehensive intervention on myopia development in elementary school children. METHODS: As a part of the Wenzhou Epidemiology of Refraction Error Study, there were 1524 participating elementary students (730 girls, 47.9%) in grades 1 to 3 from three campuses of one school, aged 7.3±0.9y, who were examined twice every year for a 2.5y follow up period. Comprehensive intervention and other reminders were given at school every semester for the intervention group. The control group did not receive comprehensive intervention and did not have reminders of it. RESULTS: There were 651 students in the intervention group [mean age 7.3±0.9y; 294 (45.2%) girls] and 737 students in the control group [mean age 7.2±0.9y; 346 (46.9%) girls]. Overall mean myopia progression during the 2.5y follow-up was -0.49±1.04 diopters (D) in the intervention group and -0.65±1.08 D in the control group (P=0.004). The majority that not get myopia at baseline spherical equivalent (SE≤-1.0 D). Their mean myopia progression during the 2.5y follow-up was -0.37±0.89 D in the intervention group and -0.51±0.93 D in the control group (27.5% reduction, P=0.009); Overall, mean axial length elongation was less in the intervention group (0.56±0.32 mm) than in the control group (0.61±0.38 mm, 10.5% reduction, P=0.009). The percentage of close reading distance (<30 cm) in the intervention group was less than in the control group (73.4% vs 76.2%, P<0.001), the percentage of everyday perform eye exercises in the intervention group was more than in the control group (27.8% vs 20.7%, P<0.001) 30mo later. CONCLUSION: The comprehensive intervention program at elementary school has a significant alleviating effect on myopia progression for children during the 2.5y follow-up, especially for those non-myopia at baseline.

Analysis of the Reliability and Repeatability of Distance Visual Acuity Measurement with EyeSpy 20/20.

Background: Visual acuity is a critical component of visual function assessment for all ages. Standardized vision testing protocols may help prevent testing inconsistencies resulting from variations in test administration and interpretation of different examiners. However, most vision assessments outside of research settings, including in doctor's offices, rarely employ standardized protocols. Validated protocols such as the Early Treatment for Diabetic Retinopathy Study (ETDRS) are frequently employed by vision researchers to ensure accurate and repeatable visual acuity measurements. Methods: This study evaluates a desktop-based standardized vision testing algorithm (EyeSpy 20/20) specifically designed for use on mobile electronic platforms. Subjects were tested on a desktop version of the EyeSpy software for both the accuracy and duration of measurement of visual acuity and compared to a e-ETDRS chart in a randomized sequence. Children were recruited for this study and tested between two different visual acuity measurement systems. Bland-Altman analysis and correlation tests were done. Results: Hundred and ten children were recruited for the study. The EyeSpy 20/20 visual acuity testing algorithm as tested with the desktop version was non-inferior to the gold standard e-ETDRS testing algorithm on a desktop platform, but statistically faster to implement when administered on the same electronic testing platform. Conclusion: EyeSpy 20/20 is a promising tool for vision screening and visual acuity evaluation in children.

Refractive change and incidence of myopia among rural Chinese children: the Handan Offspring Myopia Study.

PURPOSE: To assess the refractive change and incidence of myopia, as well as their risk factors, among Chinese rural children aged 6-17 years. METHODS: Children who completed the baseline vision examination of the Handan Offspring Myopia Study were re-examined, including both cycloplegic and non-cyloplegic autorefraction, with a mean follow-up time of 42.4±1.47 months. RESULTS: A total of 601 children (68.5%) who completed both baseline and the follow-up examinations were enrolled. The cumulative refractive change and axial length change were -0.53±1.03 diopter and 0.39±0.46 mm (-0.15 diopter/year and 0.11 mm/year), respectively. A hundred and five out of the 469 non-myopic children at baseline become myopic at the follow-up, yielding a cumulative myopia incidence of 22.4% (95% CI: 18.6% to 26.2%), or annual myopia incidence of 6.3%. After adjustment, younger age (ß=0.08, p<0.001), more myopic baseline refraction (ß=0.31, p<0.001), larger difference between cycloplegic and non-cycloplegic refraction (ß=-0.20, p=0.007) and more myopic paternal refraction (ß=0.09, p=0.007) were found to be associated with more rapid myopic refractive change. More myopic baseline refraction (relative risk (RR), 95% CI: 0.19, 0.13-0.28, p<0.001) and more myopic paternal refraction (RR, 95% CI: 0.92, 0.84-1.00, p=0.039) were also associated with myopia incidence. CONCLUSION: Relatively low myopic refractive change and myopia incidence were found in this study cohort. Children's refraction and paternal refraction were associated with both myopic refractive change and myopia incidence. Such information will be helpful for further comparisons in other rural versus urban areas of China, and other countries.

Reading Eye Movements Performance on iPad vs Print Using a Visagraph.

This study investigated reading comprehension, reading speed, and the quality of eye movements while reading on an iPad, as compared to printed text. 31 visually-normal subjects were enrolled. Two of the passages were read from the Visagraph standardized text on iPad and Print. Eye movement characteristics and comprehension were evaluated. Mean (SD) fixation duration was significantly longer with the iPad at 270 ms (40) compared to the printed text (p=0.04) at 260 ms (40). Subjects' mean reading rates were significantly lower on the iPad at 294 words per minute (wpm) than the printed text at 318 wpm (p=0.03). The mean (SD) overall reading duration was significantly (p=0.02) slower on the iPad that took 31 s (9.3) than the printed text at 28 s (8.0). Overall reading performance is lower with an iPad than printed text in normal individuals. These findings might be more consequential in children and adult slower readers when they read using iPads.

Cone parameters in different vision levels from the adaptive optics imaging.

ABSTRACT: To investigate the relationship between visual resolution and cone parameters in eyes with different levels of best corrected visual acuity (BCVA).Seventeen eyes of 10 volunteers with BCVA of 20/12.5 or better (group 1) and 16 eyes of 10 volunteers with BCVA of 20/16 (group 2) were investigated in the study. Images of the cone photoreceptors at 1.5° from the fovea were obtained using an adaptive optics (AO) retinal camera. The BCVA was obtained following a subjective refraction using a standardized logMAR visual acuity chart.The mean cone density (29,570.96 ±â€Š2489.94 cells/mm2) at 1.5° from the fovea in group 1 (BCVA ≥ 20/12.5, n = 17) was significantly greater (P < .001) than that (22,963.59 ±â€Š2987.92 cells/mm2) in group 2 (BCVA = 20/16, n = 16). The cone spacing at 1.5° from the fovea in group 1 was 6.45 ±â€Š0.28 µm (mean ±â€ŠSD), which was significantly smaller (P < .001) than 7.36 ±â€Š0.50 µm (mean ±â€ŠSD) in group 2. In the stepwise regression analysis, greater angular cone density (odds ratio [OR], 4.48; P = .005) and smaller angular cone spacing (OR, 0.60; P = .007) at 1.5° from the fovea were significantly associated with the better BCVA.The greater cone density and smaller cone spacing at the parafovea were found in eyes with BCVA of 20/12.5 or better, as compared to that in eyes with BCVA of 20/16. Knowledge of cone distribution for different BCVA levels may be beneficial for different clinical conditions.

The association between nearwork-induced transient myopia and progression of refractive error: A 3-year cohort report from Beijing Myopia Progression Study

PURPOSE: To investigate the natural change of nearwork-induced transient myopia (NITM), and its association with the progression of refractive error. METHODS: Students of the Beijing Myopia Progression Study were examined at baseline and follow-up examinations, which included cycloplegic autorefraction. Initial NITM and its decay were assessed objectively immediately after binocularly-viewing and performing a sustained 5-minute near task (20 cm). RESULTS: There were 223 students with both NITM and cycloplegic refractive data enrolled. There were 142 myopic (63.7%), 32 emmetropic (14.4%), and 49 hyperopic (22.0%) students according to their baseline cycloplegic refraction. The annual refractive change was -0.45 (-0.73, -0.21) D. From the baseline to the one-year and two-year follow-up periods, the initial NITM (median) increased significantly in the myopic students (0.16, 0.21, and 0.20D, p = 0.01, respectively). The overall proportion of NITM decay types shifted significantly from none being induced at baseline (non-induced: 17.0%, complete decay 57.4%, incomplete decay 25.6%) to incomplete decay at the 2-year follow-up (non-induced: 6.7%, complete decay 65.0%, incomplete decay 28.3%, p = 0.01). For the hyperopic students, after adjusting for risk factors, for every 1 diopter increase in the initial NITM at baseline, there was approximately a -1.48 diopter more relative myopic refractive progression (p = 0.01). No significant association was found between refractive change and the NITM parameters for either the myopic or emmetropic students after adjusting for the same confounders. However, this relation was significant in the hyperopes (p = 0.01). CONCLUSION: NITM was only found to be significantly associated with the progression of a myopic refractive shift among the hyperopes

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The association between nearwork-induced transient myopia and progression of refractive error: A 3-year cohort report from Beijing Myopia Progression Study.

PURPOSE: To investigate the natural change of nearwork-induced transient myopia (NITM), and its association with the progression of refractive error. METHODS: Students of the Beijing Myopia Progression Study were examined at baseline and follow-up examinations, which included cycloplegic autorefraction. Initial NITM and its decay were assessed objectively immediately after binocularly-viewing and performing a sustained 5-minute near task (20 cm). RESULTS: There were 223 students with both NITM and cycloplegic refractive data enrolled. There were 142 myopic (63.7%), 32 emmetropic (14.4%), and 49 hyperopic (22.0%) students according to their baseline cycloplegic refraction. The annual refractive change was -0.45 (-0.73, -0.21) D. From the baseline to the one-year and two-year follow-up periods, the initial NITM (median) increased significantly in the myopic students (0.16, 0.21, and 0.20D, p = 0.01, respectively). The overall proportion of NITM decay types shifted significantly from none being induced at baseline (non-induced: 17.0%, complete decay 57.4%, incomplete decay 25.6%) to incomplete decay at the 2-year follow-up (non-induced: 6.7%, complete decay 65.0%, incomplete decay 28.3%, p = 0.01). For the hyperopic students, after adjusting for risk factors, for every 1 diopter increase in the initial NITM at baseline, there was approximately a -1.48 diopter more relative myopic refractive progression (p = 0.01). No significant association was found between refractive change and the NITM parameters for either the myopic or emmetropic students after adjusting for the same confounders. However, this relation was significant in the hyperopes (p = 0.01). CONCLUSION: NITM was only found to be significantly associated with the progression of a myopic refractive shift among the hyperopes.

The Effect of Eye Exercises of Acupoints on Myopia Progression: A 3-Year Cohort Report from the Beijing Myopia Progression Study.

PURPOSE: To investigate the impact of eye exercises of acupoints on myopic progression among Chinese urban students. METHODS: The Beijing Myopia Progression Study (BMPS) was a three-year cohort study, with 386 students (aged 6-17 years) enrolled at baseline. These students were invited to be reexamined in the years 2011, 2012, and 2013. The student's cycloplegic refraction at each visit and the parental non-cycloplegic refraction at baseline were performed. Students were also required to complete the eye exercise of acupoints questionnaire and the convergence insufficiency symptom survey (CISS). RESULTS: At the final follow-up, 226 students (57.2%) with complete refraction and eye exercises questionnaire data were enrolled in the present study. In the multivariate analysis, only students who performed the eye exercises twice or more per day had less myopic refractive change (ß=0.32, p=0.04), as compared to those who performed the eye exercises less than twice per day. No significant association was found between the CISS score and the refractive change for items in the eye exercises questionnaire. CONCLUSION: In this study cohort, the Chinese eye exercises of acupoints had a modest effect on reducing myopic progression among Chinese urban students aged 6 to 17 years. The precise mechanism remains unclear, especially in the absence of a control group.

Effect of Intraocular Pressure on Aerosol Density Generated by Noncontact Tonometer Measurement.

PRECIS: Aerosols generated by a noncontact tonometer (NCT) were quantified. There was a positive correlation between aerosols and intraocular pressure (IOP), and the concentration of aerosols beside the air jet port was the highest. PURPOSE: To investigate the effects of IOP on the aerosol density generated during the use of an NCT and provide references and suggestions for daily protection of ophthalmic medical staff during the coronavirus disease-19 (COVID-19) outbreak. OBJECTIVE AND METHODS: This cross-sectional clinical trial included 214 eyes of 140 patients from a hospital in Wenzhou city, Zhejiang Province. All subjects' IOPs were measured by an NCT (39 eyes with low IOP, 90 eyes with normal IOP, 37 eyes with moderately high IOP, and 48 eyes with very high IOP) between March 7 and June 17, 2020. The density of particulate matter (PM) 2.5 and PM10 generated during the process of IOP measurement with an NCT was analyzed. IOP values were recorded simultaneously. The aerosols generated during different IOP measurements were plotted in scatter plots. RESULTS: PM2.5 was generated more at the air jet port of the tonometer during the process of IOP measurement (H=2.731, P=0.019). Larger quantities of PM2.5 and PM10 were generated when the IOP was higher, and these differences were statistically significant (PM2.5: H=119.476, P<0.001; PM10: H=160.801, P<0.001). Linear correlation analysis with one variable demonstrated that IOP had significantly positive correlations with PM2.5 (r=0.756, P<0.001) and PM10 (r=0.864, P<0.001). CONCLUSIONS: Aerosols can be generated while using an NCT to measure IOP, and aerosols and IOP are positively correlated. Patients with moderately high IOP or very high IOP tend to generate more aerosols during the IOP measurement. The concentration of aerosols beside the air jet port was the highest.

Genome-Wide Association of Genetic Variants With Refraction, Axial Length, and Corneal Curvature: A Longitudinal Study of Chinese Schoolchildren.

BACKGROUND: Myopia is a common eye disorder that is approaching epidemic proportions worldwide. A genome-wide association study identified AREG (rs12511037), GABRR1 (rs13215566), and PDE10A (rs12206610) as being associated with refractive error in Asian populations. The present study investigated the associations between these three genetic variants and the occurrence and development of myopia, spherical equivalent refraction (SER), axial length (AL), and corneal curvature (CC) in a cohort of southeastern Chinese schoolchildren. METHODS: We examined and followed 550 children in grade 1 enrolled in the Wenzhou Epidemiology of Refractive Error (WERE) project. During the 4-year follow-up, non-cycloplegic refraction was evaluated twice each year, and the AL and CC were measured once every year. Age, sex, and the amounts of time spent on near work and outdoors were documented with a questionnaire. Sanger DNA sequencing was used to genotype single nucleotide polymorphisms (SNPs). SNPtest software was used to identify potential genetic variants associated with myopia, SER, AL, and CC. Ten thousand permutations were used to correct for multiple testing. RESULTS: In total, 469 children, including 249 (53.1%) boys and 220 (46.9%) girls, were included in analyses. The mean age of all the children was 6.33 ± 0.48 years. After adjusting for age, sex, time spent on near work and time spent outdoors, neither the genotypes nor the allele frequencies of the three SNPs were significantly associated with myopic shift, incident myopia or the change in SER. After adjusting for age, sex, near-work time and outdoor time with 10,000 permutations, the genotype AREG (rs12511037) was associated with an increase in AL (P'-values for the dominant, recessive, additive and general models were 0.0032, 0.0275, 0.0045, and 0.0099, respectively); the genotype PDE10A (rs12206610) was associated with a change in CC in the additive (P' = 0.0096), dominant (P' = 0.0096), and heterozygous models (P' = 0.0096). CONCLUSION: These findings preliminarily indicate that AREG SNP rs12511037 and PDE10A SNP rs12206610 are etiologically relevant for ocular traits, providing a basis for further exploration of the development of myopia and its molecular mechanism. However, elucidating the role of AREG and PDE10A in the pathogenesis of myopia requires further animal model and human genetic epidemiology studies. This trial is registered as ChiCTR1900020584 at www.Chictr.org.cn.

Generational Difference of Axial Length and Its Risk Factors in Urban and Rural China.

PURPOSE: To compare the axial length difference (ALD) and the estimated generational axial length shift (ALS) from parents to their children and its risk factors in urban and rural China. METHODS: Participants were enrolled from two longitudinal cohort studies, the Beijing Myopia Progression Study (BMPS) and the Handan Offspring Myopia Study (HOMS). Ocular biometry was performed in both parents and their children. ALD was defined as the difference between the children's axial length and the corresponding parental axial length. Generational ALS was estimated according to a binominal prediction model at 18 years of age. RESULTS: 237 and 380 urban and rural Chinese children (6-17 years) and their parents from the BMPS and HOMS, respectively, were enrolled. Children's axial length was estimated to be closest to the parental axial length at 11 and 9 years of age in the urban and rural areas, respectively; the estimated generational ALS would be 1.53 and 0.57 mm, respectively. Multivariable regression analysis revealed that older children (urban ß = 0.26, p < 0.001; rural ß = 0.11, p < 0.001) and males had larger ALD (urban ß = 0.55, p < 0.001; rural ß = 0.52, p < 0.001) in both areas. Furthermore, urban children with more educated parents (fathers: ß = -0.30, p=0.002; mothers: ß = -0.29, p=0.004) and more outdoor activity (ß = -0.23, p=0.006) had a less ALD. CONCLUSIONS: The urban generational axial length shift was estimated to be approximately 1 mm longer than that of the rural area. These results suggest different environmental effects on the ocular development in these two populations of Chinese children.

Simultaneous Changes in Astigmatism with Noncycloplegia Refraction and Ocular Biometry in Chinese Primary Schoolchildren.

PURPOSE: To assess the changing profile of astigmatism in Chinese schoolchildren and the association between astigmatism changes and ocular biometry. METHODS: We examined and followed up 1,463 children aged 6-9 years from Wenzhou, China. We measured noncycloplegic refraction twice each year and tested axial length (AL) and corneal radius of curvature (CRC) annually for two years. We defined clinically significant astigmatism (CSA) as ≤-0.75 diopter (D) and non-CSA astigmatism as ≤0 to >-0.75 D. RESULTS: Prevalence of CSA at baseline was 22.4% (n = 327) and decreased to 20.3% (n = 297) at the two-year follow-up (P = 0.046). Ninety-two (8.1%) non-CSA children developed CSA. In multiple regression, after adjusting for age, gender, baseline cylinder refraction, and axis, children who had longer baseline ALs (>23.58 mm; odds ratio (OR) = 5.19, 95% confidence interval (CI): 2.72-9.90) and longer baseline AL/CRC ratio (>2.99, OR = 4.99, 95% CI: 2.37-10.51) were more likely to develop CSA after two years. Four-hundred and two (27.5%) children had increased astigmatism, 783 (53.5%) had decreased, and 278 (19.0%) had no change during the two-year follow-up. Children with increased astigmatism had longer baseline ALs (23.33 mm, P < 0.001), higher AL/CRC ratios (2.99 mm, P < 0.001), and more negative spherical equivalent refraction (SER) (-0.63 D, P < 0.001) compared with the decreased and no astigmatism change subgroups. Also, children in the increased astigmatism subgroup had more AL growth (0.68 mm, P < 0.001), higher increases in AL/CRC ratio (0.08, P < 0.001), and more negative SER change (-0.86 D, P < 0.001) compared with the decreased and no astigmatism change subgroups. CONCLUSIONS: The prevalence of astigmatism decreased slightly over the two-year study period. Longer ALs and higher AL/CRC ratios were independent risk factors for developing CSA. Increased astigmatism was associated with AL growth, AL/CRC ratio increases, and the development of myopia. This trial is registered with ChiCTR1800019915.

Comparing habitual and i. Scription refractions.

BACKGROUND: Many patients voice concerns regarding poor night vision, even when they see 20/20 or better in the exam room. During mesopic and scotopic conditions the pupil size increases, increasing the effects on visual performance of uncorrected (residual) refractive errors. The i.Scription refraction method claims to optimize traditional refractions for mesopic and scotopic conditions, by using the information that the Zeiss i.Profilerplus gathers of ocular aberrations (low and high order). The aim of this study was to investigate any differences between habitual and i.Scription refractions and their relationship to night vision complaints. METHODS: Habitual, subjective, and i.Scription refractions were obtained from both eyes of eighteen subjects. Low and high order aberrations of the subjects were recorded with the Zeiss i.Profilerplus. The root mean square (RMS) metric was calculated for small (3 mm) and maximum pupil sizes. Subjects rated their difficulty with driving at night on a scale of 1-10. RESULTS: There was a statistically significant difference between the habitual and i.Scription refractions on both the sphere and cylinder values [(t = 3.12, p < 0.01), (t = 5.39, p < 0.01)]. The same was found when comparing the subjective and i.Scription refractions [(t = 2.31, p = 0.03), (t = 2.54, p = 0.02)]. There were no significant differences found when comparing the sphere and cylinder values between the habitual and subjective refractions or on any combination of spherical equivalent refraction. The maximum pupil size of the subject population on this study, measured with the i.Profilerplus, was 4.8 ± 1.04 mm. Ten out of the eighteen subjects had discomfort at night with an average magnitude of 4 ± 2.7. Ratings of difficulty with night vision correlated with the change in spherical equivalent correction between the habitual and i.Scription refractions (p = 0.01). A sub-analysis of myopic subjects (n = 15) showed an increase in the significance of this relationship (p = 0.002). CONCLUSIONS: The i.Scription method improves night vision by correcting the sphere and cylinder more precisely. There was a correlation between the amount of change in the cylinder value between habitual and i.Scription prescriptions and the magnitude of the reported visual discomfort at night.

Near work, outdoor activity, and myopia in children in rural China: the Handan offspring myopia study.

BACKGROUND: The near work and outdoor activity are the most important environmental risk factors for myopia. However, data from Chinese rural children are relatively rare and remain controversial. Therefore, the purpose of this study was to evaluate the relationship of both near work and outdoor activities with refractive error in rural children in China. METHODS: In this cross-sectional study, 572 (65.1%) of 878 children (6-18 years of age) were included from the Handan Offspring Myopia Study (HOMS). Information from the parents on these children, as well as the parent's non-cycloplegic refraction, were obtained from the database of the Handan Eye Study conducted in the years 2006-2007. A comprehensive vision examination, including cycloplegic refraction, and a related questionnaire, were assessed on all children. RESULTS: The overall time spent on near work and outdoor activity in the children was 4.8 ± 1.6 and 2.9 ± 1.4 h per day, respectively. Myopic children spent more time on near work (5.0 ± 1.7 h vs.4.7 ± 1.6 h, p = 0.049), while no significant difference was found in outdoor activity hours (2.8 ± 1.3 h vs. 3.0 ± 1.4 h, p = 0.38), as compared to non-myopic children. In the multiple logistic analysis, in general, no association between near work and myopia was found after adjusting for the children's age, gender, parental refractive error, parental educational level, and daily outdoor activity hours [odds ratio (OR), 95% confidence interval (CI): 1.10, 0.94-1.27]. However, a weak protective effect of the outdoor activity on myopia was found (OR, 95% CI: 0.82, 0.70-0.96), after adjusting for similar confounders. CONCLUSIONS: In general, no association between near work and myopia was found, except for the high near work subgroup with moderate outdoor activity levels. A weak protective effect of outdoor activity on myopia in Chinese rural children was observed.

The difference between cycloplegic and non-cycloplegic autorefraction and its association with progression of refractive error in Beijing urban children.

PURPOSE: To investigate the difference between cycloplegic and non-cycloplegic autorefraction and its association with the progression of refractive error in Beijing urban children. METHODS: A total of 386 children aged 6-17 years were enrolled in the baseline investigation of the Beijing Myopia Progression Study in 2010. They were invited for follow-up vision examinations in the years 2011, 2012, and 2013, including cycloplegic (cyclopentolate 1%, three times) autorefraction. We investigated the difference between the cycloplegic spherical equivalent (SE) and the non-cycloplegic SE (DSE) provided by autorefraction and its association with refractive error progression. The progression of refractive error was defined as the difference between the cycloplegic SE at follow-up and at baseline. RESULTS: Two hundred and nineteen children (57%) with completed refractive data (mean ± standard deviation: -1.36 ± 2.44 D at baseline) were ultimately enrolled. The DSE reduced from 0.51 ± 0.72 D at baseline to 0.19 ± 0.43 D in the third year of follow-up (p = 0.01). The baseline DSE was positively associated with the children's baseline cycloplegic refraction (ß = 0.193 dioptre dioptre-1 , p < 0.001). After further divided by refractive status, the DSE was consistently higher in the hyperopic group than in either the emmetropic or myopic groups at each follow-up (all p < 0.001). In the multivariate regression analysis, the myopic children with larger baseline DSE (ß = -0.404 dioptre dioptre-1 , p = 0.01) exhibited more myopic refractive change. However, baseline DSE was not found to be a significant risk factor (relative risk, 95% confidence interval: 1.06, 0.79-1.41) for those with newly developed myopia. CONCLUSION: In this sample, the children's DSE was found to be increased as the hyperopic refraction increased. Furthermore, greater the DSE was associated with the progression of refractive error among the myopic children, but not with the onset of myopia.

Myopigenic Activity Change and Its Risk Factors in Urban Students in Beijing: Three-Year Report of Beijing Myopia Progression Study.

PURPOSE: To investigate the myopigenic activity change and its risk factors in urban students in Beijing. METHODS: A total of 241 primary or secondary students aged 6-17 years from the Beijing Myopia Progression Study (BMPS) were re-examined 3 years after their baseline enrollment. A detailed questionnaire was administered to assess myopigenic activities at both baseline and at the 3-year follow-up. Altogether, 217 students (90.0%) with completed data were included in the analysis. RESULTS: Compared to baseline, primary students (n = 123) had significant increases in outdoor sports time (mean ± standard deviation: 3.5 ± 4.3 vs. 2.4 ± 3.0 hours/week, p = 0.02), near work time (32.1 ± 13.4 vs. 24.8 ± 9.2 hours/week, p < 0.001), diopter hours (128.8 ± 53.3 vs. 97.5 ± 35.9 diopter hours/week, p < 0.001), and indoor time (53.8 ± 22.8 vs. 41.4 ± 16.9 hours/week, p < 0.001) at the 3-year follow-up. At both baseline and follow-up, females spent less time than males on outdoor sports (baseline: 2.4 ± 2.8 vs. 4.0 ± 5.2 hours/week, p = 0.006; follow-up: 2.3 ± 3.1 vs. 5.1 ± 5.0 hours/week, p < 0.001), and total outdoors (baseline: 11.9 ± 7.9 vs. 14.4 ± 9.5 hours/week, p = 0.03; follow-up: 10.5 ± 8.2 vs. 13.9 ± 9.6 hours/week, p = 0.005). In the multivariate regression analysis after adjustment by student's gender, younger students had more increase in both near work time (slope = -0.99 hours/week for age, p = 0.009) and indoor time (slope = -2.04 hours/week for age, p = 0.001). CONCLUSIONS: During the 3-year follow-up, primary students had more myopigenic activities. Female students had more myopigenic activities than males at both baseline and follow-up. Children's age was a significant risk factor for this myopigenic activity change.

Eye exercises of acupoints: their impact on myopia and visual symptoms in Chinese rural children.

BACKGROUND: Chinese traditional "eye exercises of acupoints" have been advocated as a compulsory measure to reduce visual symptoms, as well as to retard the development of refractive error, among Chinese students for decades. The exercises are comprised of a 5-min, bilateral eye acupoint self-massage. This study evaluated the possible effect of these eye exercises among Chinese rural students. METHODS: Eight hundred thirty-six students (437 males, 52.3 %), aged 10.6 ± 2.5 (range 6-17) years from the Handan Offspring Myopia Study (HOMS) who completed the eye exercises and vision questionnaire, the convergence insufficiency symptom survey (CISS) questionnaire, and had a cycloplegic refraction were included in this study. RESULTS: 121 (14.5 %) students (64 males, 52.9 %) performed the eye exercises of acupoints in school. The multiple odds ratio (OR) and 95 % confidence interval (CI) for those having a "serious attitude" towards performing the eye exercises (0.12, 0.03-0.49) demonstrated a protective effect for myopia, after adjusting for the children's age, gender, average parental refractive error, and the time spent on near work and outdoor activity. The more frequently, and the more seriously, the students performed the eye exercises each week, the less likely was their chance of being myopic (OR, 95 % CI: 0.17, 0.03-0.99), after adjusting for the same confounders. However, neither the "seriousness of attitude" of performing the eye exercises (multiple ß coefficients: -1.58, p = 0.23), nor other related aspects of these eye exercises, were found to be associated with the CISS score in this sample. CONCLUSIONS: The traditional eye exercises of acupoints appeared to have a modest protective effect on myopia among these Chinese rural students aged 6-17 years. However, no association between the eye exercises and near vision symptoms was found.

Effect of defocus on response time in different age groups: A pilot study / Efecto del desenfoque en el tiempo de respuesta en diferentes grupos de edad: estudio piloto

Purpose: To assess the response time associated with visual performance (VP) tasks in the presence of defocus in different presbyopic populations. Methods: 58 eyes between the ages of 35 and 50 years were studied. Subjects were categorized as pre-presbyopic (35-39 years), early-presbyopic (40-45 years), and mid-presbyopic (46-50 years). VP measurements obtained monocularly included distance and near high contrast (HC) and low contrast (LC) optotype recognition, and contrast threshold at 12cpd for different defocus magnitudes between 0D and 3D in 1D steps. Response time defined as the time taken to recognize and verbalize an optotype, was compared among different presbyopic age groups. Results: From 58 eyes, mean (SD) response time for high contrast distance visual acuity for 0D through 3D ranged between 1.48 (0.23) and 1.87 (0.31)s, whereas low contrast distance visual acuity ranged between 1.5 (0.22) and 2.09 (0.49)s. Mean response time for high contrast near visual acuity for 0D through 3D ranged between 1.56 (0.19) and 2.23 (0.45)s. However, for low contrast near visual acuity it ranged between 1.75 (0.32) and 2.71 (0.94)s. Mean (SD) response time for 12cpd ranged between 2.11 (0.50) and 5.72 (1.09)s. ANOVA revealed a significant difference in response time for distance, near visual acuity and contrast sensitivity as a function of defocus for different age groups. Conclusions: Response time is increased in the presence of increasing defocus for both distance and near visual acuity and could impact on performance for critical tasks. Full correction of visual acuity at distance and near in presbyopes is warranted always (AU)

Objetivo: Evaluar el tiempo de respuesta asociado a las tareas del desempeño visual (DV) en presencia de desenfoque, en diferentes poblaciones présbitas. Métodos: Se estudiaron 58 ojos de personas en edades comprendidas entre 35 y 50 años. Se clasificó a los sujetos conforme a las siguientes categorías: pre-presbicia (35-39 años), presbicia temprana (40-45 años), y presbicia media (46-50 años). Las mediciones del desempeño visual obtenidas de forma monocular incluyeron el reconocimiento de optotipos cercanos y lejanos de alto y bajo contraste y el umbral de contraste a 12cpd para las diferentes magnitudes de desenfoque, entre 0D y 3D, a intervalos de 1D. El tiempo de respuesta es el tiempo empleado en reconocer y verbalizar un optotipo, y se comparó entre los diferentes grupos de edad de los individuos présbitas. Resultados: De los 58 ojos, el tiempo de respuesta media (DE) para la agudeza visual de la distancia a alto contraste, entre 0D y 3D, osciló entre 1,48 (0,23) y 1,87 (0,31) segundos, mientras que la agudeza visual de la distancia a bajo contraste osciló entre 1,5 (0,22) y 2,09 (0,49) segundos. El tiempo de respuesta media para la agudeza visual cercana de alto contraste entre 0D y 3D osciló entre 1,56 (0,19) y 2,23 (0,45) segundos. Sin embargo para la agudeza visual cercana de bajo contraste osciló entre 1,75 (0,32) y 2,71 (0,94) segundos. El tiempo de respuesta media (DE) para 12cpd osciló entre 2,11 (0,50) y 5,72 (1,09) segundos. ANOVA reveló una diferencia significativa en cuanto al tiempo de respuesta para la distancia, agudeza visual cercana y sensibilidad de contraste como función del desenfoque para los diferentes grupos de edad. Conclusiones: El tiempo de respuesta se eleva al incrementarse el desenfoque en la agudeza visual lejana y cercana, pudiendo repercutir sobre el desempeño de ciertas tareas esenciales. La corrección plena de la agudeza visual cercana y lejana en individuos présbitas debe de ser siempre garantizada (AU)