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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 (β=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.

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.

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

PurposeTo assess the refractive change and incidence of myopia, as well as their risk factors, among Chinese rural children aged 6–17 years.MethodsChildren 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.ResultsA 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 (β=0.08, pConclusionRelatively 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.

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 ± 2489.94 cells/mm2) at 1.5° from the fovea in group 1 (BCVA ≥ 20/12.5, n = 17) was significantly greater (P

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

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 β = 0.26, p<0.001; rural β = 0.11, p<0.001) and males had larger ALD (urban β = 0.55, p<0.001; rural β = 0.52, p<0.001) in both areas. Furthermore, urban children with more educated parents (fathers: β = −0.30, p=0.002; mothers: β = −0.29, p=0.004) and more outdoor activity (β = −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.

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.

To investigate the influence of daily activities on myopic refractive change and myopic onset in Chinese urban students. The Beijing Myopia Progression Study was a 3-year cohort study. Cycloplegic refraction and a daily activity questionnaire were assessed at baseline and at follow-up examinations. Refractive change was defined as the difference in cycloplegic spherical equivalent (SE) between the final follow-up and baseline. 386 students were initially enrolled in the baseline study. At the final follow-up, 222 students (57.5 %) with completed refractive error and daily activity data were analyzed. These students spent 0.32 ± 2.33 h/day more on near work (p = 0.04), and 0.21 ± 1.31 h/day less on outdoor leisure (p = 0.02), than they did at baseline. In the multivariate analysis, the younger among the secondary students (β = 0.06, p

The aim was to assess non-cycloplegic objective refraction in darkness using an open-field auto-refractor, and furthermore to compare it with distance cycloplegic subjective refraction and distance cycloplegic retinoscopy in the light, in children and young adults.Twenty-three, visually-normal, young-adults (46 eyes) ages 23 to 31 years, and five children (10 eyes) ages five to 12 years, participated in the study. The spherical component of their refraction ranged from -2.25 D to +3.75 D with a mean of +1.80 D, and a mean cylinder of -0.70 D. Three techniques were used to assess refractive error. An objective measure of the non-cycloplegic refractive state was obtained using an open-field autorefractor (WAM-5500) after five minutes in the dark to allow for dissipation of accommodative transients and relaxation of accommodation. In addition, both distance retinoscopy and subjective distance refraction were performed following cycloplegia (Cyclopentolate, 1%) using conventional clinical procedures. All measurements were obtained on the same day within a single session. The spherical component of the refraction was compared among the three techniques in both the children and adults.There was no significant difference in spherical refraction among the three techniques: non-cycloplegic objective refraction in the dark, distance cycloplegic retinoscopy and distance cycloplegic subjective refraction, in either the adults [F(2, 137) = 0.79, p = 0.45] or the children [F(2, 27) = 0.47, p = 0.62]. Mean difference in the spherical component between refraction in the dark and the cycloplegic distance retinoscopy was -0.34 D (r = 0.89) in the adults and +0.14 D (r = 0.96) in the children. The mean difference in spherical component between refraction in the dark and the cycloplegic distance subjective refraction was -0.25 D (r = 0.92) in the adults and -0.05 D (r = 0.95) in the children.Comparison of the spherical refractive component between the three techniques was not significantly different and furthermore, they were highly correlated in both the children and adults in this pilot study. Non-cycloplegic refraction in the dark may provide a reliable adjunct or alternative to conventional cycloplegic refraction in both children and young adults.

The aim was to determine the characteristics of near work-induced transient myopia (NITM) in asymptomatic Indian subjects and the influence of target size and contrast.Two studies were conducted: First, 24 myopes and 24 emmetropes viewed four targets (N8 and N12 with 50 and 90 per cent contrasts) placed at 0.2 m for five minutes. The refractive status was assessed objectively, before and after carrying out the near task, with the Grand Seiko WAM-5500 open-field autorefractor under monocular viewing conditions. Second, a different group of 24 myopes and 24 emmetropes viewed a N12 target with 90 per cent contrast for 60 minutes with pre- and post-refractive state measurements repeated as above. NITM was defined as the difference between pre-task and post-task distance refraction.In the first study, myopes demonstrated an initial post-task myopic shift of 0.21 D, whereas emmetropes demonstrated a small hyperopic shift of 0.07 D (p 0.001). The myopes demonstrated a decay time constant of 6.07 seconds. There was no effect of target size or contrast on the magnitude of the NITM or the decay time constant (p 0.05). In the second study, myopes showed a NITM of 0.31 D, which was significantly greater than emmetropes (p 0.001). The myopes demonstrated a decay time constant of 8.16 seconds.The magnitude of the NITM was higher in myopes compared to emmetropes for both five minute and 60 minute viewing time. The NITM decayed slightly faster than that found in previous literature for some other ethnic groups. Potential reasons for these findings are discussed.

The aim of the study was to evaluate the objective and subjective visual performance of custom toric contact lenses (TL) and their spherical off-the-shelf counterparts (SL) in subjects with low amounts of astigmatism.Twenty-three habitual soft lens wearers (40 eyes, 25-35 years) manifesting 0.50-1.00DC and ≤±3.00DS were recruited. Air Optix Aqua (Lotrafilcon B) was fit using the spherical equivalent of the manifest refraction. Intelliwave toric in Efrofilcon A (Definitive) was fit using the manifest refraction and keratometric data. Comprehensive visual performance tests were done through manifest refraction in a trial frame; in SL; and in TL. A subjective evaluation of quality of vision was also obtained.ANOVA revealed that, at the morning visit (AM), high contrast logMAR distance visual acuity (HCDVA) was significantly better (p0.01) in spectacles as compared to SL. A similar trend was noted at the afternoon visit (PM). In addition, at the PM visit, HCDVA was significantly better (p0.01) for TL as compared to their SL. ANOVA revealed that, at the PM visit, low contrast distance visual acuity (LCDVA) was significantly better (p=0.05) in spectacles as compared to SL. None of these differences were clinically significant. In addition, no statistically significant difference (p0.05) in subjective vision rating scores was noted between SL and TL.The present investigation found no clinically significant difference in visual performance between spherical and toric soft contact lenses in low astigmats.

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. Electronic supplementary material The online version of this article (10.1186/s12886-017-0598-9) contains supplementary material, which is available to authorized users.

Purpose: To investigate retrospectively, based on routine clinical records in an optometric office, the effect of refractive under-correction of the myopic spectacle prescription on myopic progression in children and young adults. Methods: Patient records of children and young-adult myopes in a private optometric practice in Glendale, Arizona, USA, were initially reviewed to identify those that met the criteria. Information collected from the patient records included: age, gender, the dates and number of their visits (more than one visit was required for use of the data), final prescription, and non-cycloplegic subjective refraction. For each patient visit, the difference in spherical equivalent (SE) between the subjective refraction for maximum visual acuity and the final prescription was calculated for both the left and right eyes. Myopia progression was defined as the difference in SE between the final subjective refraction of the previous visit and that of the subsequent visit. Based on the study criteria, a total of 275 patient visits were obtained from the data collected in 76 patients. Results: A significant positive correlation was found between the magnitude of under-correction of the refractive error and myopic progression (r = 0.301, p

Purpose The aim of the present study was to compare the objective and subjective visual performance of three different soft multifocal contact lenses. Methods 10 subjects (habitual soft contact lens wearers) between the ages of 40 and 45 years participated in the study. Three different multifocal silicone hydrogel contact lenses (Acuvue Oasys, Air Optix and Biofinity) were fit within the same visit. All the lenses were fit according to the manufacturers’ recommendation using the respective fitting guide. Visual performance tests included low and high contrast distance and near visual acuity, contrast sensitivity, range of clear vision and through-focus curve. Objective visual performance tests included measurement of open field accommodative response at different defocus levels and optical aberrations at different viewing distances. Results Accommodative response was not significantly different between the three types of multifocal contact lenses at each of the accommodative stimulus levels (p > 0.05). Accommodative lag increased for higher stimulus levels for all 3 types of contact lenses. Ocular aberrations were not significantly different between these 3 contact lens designs at each of the different viewing distances (p > 0.05). In addition, optical aberrations did not significantly differ between different viewing distances for any of these lenses (p > 0.05). ANOVA revealed no significant difference in high and low contrast distance visual acuity as well as near visual acuity and contrast sensitivity function between the 3 multifocal contact lenses and spectacles (p > 0.05). Conclusions There was no statistically significant difference in accommodative response, optical aberrations or visual performance between the 3 multifocal contact lenses in early presbyopes.

Objective: To assess the magnitude of nearwork-induced transient myopia (NITM) under binocular viewing conditions separately in each eye of individuals with mild to moderate anisometropia to determine the relationship between NITM and their interocular refractive error. Methods: Forty-three children and young adults with anisometropia [cycloplegic spherical equivalent (SE) difference >1.00 D] were tested (ages 9-28 years). NITM was measured with binocular viewing separately in each eye after binocularly performing a sustained near task (5 D) for 5 min incorporating a cognitive demand using an open-field, infrared autorefractor (Grand-Seiko, WAM-5500). Data were averaged over 10 s bins for 3 min in each eye. Initial NITM, its decay time (DT), and its decay area (DA) were determined. A-scan ultrasound ocular biometry was also performed to determine the axial length of each eye. Results: The more myopic eye exhibited increased initial NITM, DT, and DA as compared to the less myopic eye (0.21 ± 0.16 D vs 0.15 ± 0.13 D, p = 0.026; 108.4 ± 64.3 secs vs 87.0 ± 65.2 secs, p = 0.04; and 17.6 ± 18.7 D*secs vs 12.3 ± 15.7 D*secs, p = 0.064), respectively. The difference in DA and the difference in SE between the more versus less myopic eye were significantly correlated (r = 0.31, p = 0.044). Furthermore, 63% (27/43), 56% (24/43), and 70% (30/43) of the more myopic eyes exhibited increased initial NITM, longer DT, and larger DA, respectively, than found in the less myopic eye. Conclusions: In approximately two-thirds of the anisometropic individuals, the initial NITM and its decay area were significantly increased in the more myopic eye as compared to the less myopic eye. NITM may play an important role in the development of interocular differences in myopia, although a causal relationship is yet to be established. Furthermore, the findings have potentially important implications regarding accommodative control and interocular accommodative responsitivity in anisometropia, in particular for anisomyopia.

Purpose. To investigate the relationship between parental refractive error and the nearwork-induced transient myopia (NITM) characteristics of their children. Methods. Three hundred sixty children (173 boys and 187 girls) aged 6 to 17 years were tested. Initial NITM and its decay time (DT) were assessed objectively (WAM-5500, Grand-Seiko) immediately after binocularly viewing and performing a sustained near task (5 diopters [D]) for 5 minutes, incorporating a cognitive demand with full distance refractive correction in place. The NITM was classified into three categories: low (G0.15 D), moderate (0.15 to 0.30 D), or high (Q0.30 D), whereas its decay was classified into two categories, namely, complete or incomplete. In addition, the children were divided into three groups based on the number of myopic parents (none, one, or two) and into four groups based on the level of parental myopia (no, low, moderate, or high). Results. Neither paternal nor maternal refractive error was associated with either their children’s initial NITM magnitude or its DT in the myopic, emmetropic, or hyperopic groups or the combined group. No significant differences (p 9 0.05) in the NITM magnitude, DT, or decay time constant were found as related to the number of myopic parents or level of parental myopia. Multiple odds ratio for incomplete decay of NITM did not change significantly (p 9 0.05) with either an increase in number of myopic parents or level of parental myopia. Conclusions. There was no association between parental refractive error and their children’s NITM characteristics. This suggests a primary environmental basis for the NITM characteristics in the children. (Optom Vis Sci 2013;90:00Y00)

Aims To report the refractive error difference (RED) between parents and their children and the estimated single generational myopic shift in an urban area in China. Methods 395 children aged 6–17 years and their parents, who had been enrolled in the Beijing Myopia Progression Study were included. Cycloplegic and non-cycloplegic refraction of the children and parents were performed, respectively. RED was defined as the difference between the average parental spherical equivalent (SE) and the average SE of their children. Binomial fitted curves of RED were plotted as a function of the children's age. Generational myopic shift was defined as the estimated RED according to the prediction model at the age of 18 years. Results 395 families were enrolled. The RED was positively correlated with the children's age (rspearman=0.58, p

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 (β = 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 (β = −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.

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 β 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. Electronic supplementary material The online version of this article (doi:10.1186/s12906-016-1289-4) contains supplementary material, which is available to authorized users.

Purpose. The purpose of the present study was to describe the baseline refractive and nearwork-induced transient myopia (NITM) characteristics of the Beijing Myopia Progression Study, a 3-year cohort study, that has three overall specific aims: to investigate the natural history of NITM in schoolchildren living in the inner city of Beijing aged between 7 and 17 years; to investigate the possible relation between NITM and permanent myopia; and to determine the possible associations with NITM (eg, parental history). Methods. Three hundred eighty-six students (187 males and 199 females) were enrolled. The mean ages were 8.4 +/- 1.1 years and 14.2 +/- 1.6 years for the primary school and secondary school students, respectively. Baseline refractive aspects were determined clinically. Initial NITM and its decay were assessed objectively immediately after binocularly viewing and performing a sustained near task (5 minutes; 5 diopters [D]), incorporating a cognitive demand with full distance refractive correction in place. Results. Initial NITM (mean +/- SD) / decay time (median, first quartile, and third quartile) was 0.18 +/- 0.16 D / 50 (20, 90) seconds, 0.09 +/- 0.13 D / 30 (10, 40) seconds, and 0.10 +/- 0.19 D / 20 (10, 40) seconds among the myopic, emmetropic, and hyperopic students, respectively, for the combined school levels. Initial NITM and decay time were significantly larger/longer in the myopic versus the other two refractive groups. Conclusions. The present findings demonstrate that in a large sample of school-aged children with myopia, the initial NITM magnitude was significantly larger and the decay duration was significantly longer than that observed in age-matched children with either emmetropia or hyperopia. Follow-up for the next 3 years will provide insight into the possible role of NITM in the development of permanent myopia. (Optom Vis Sci 2012; 89: 1725-1733)

We seek unbiased methods for estimating the target vergence required to maximize visual acuity based on wavefront aberration measurements. Experiments were designed to minimize the impact of confounding factors that have hampered previous research. Objective wavefront refractions and subjective acuity refractions were obtained for the same monochromatic wavelength. Accommodation and pupil fluctuations were eliminated by cycloplegia. Unbiased subjective refractions that maximize visual acuity for high contrast letters were performed with a computer controlled forced choice staircase procedure, using 0.125 diopter steps of defocus. All experiments were performed for two pupil diameters (3mm and 6mm). As reported in the literature, subjective refractive error does not change appreciably when the pupil dilates. For 3mm pupils most metrics yielded objective refractions that were about 0.1D more hyperopic than subjective acuity refractions. When pupil diameter increased to 6mm, this bias changed in the myopic direction and the variability between metrics also increased. These inaccuracies were small compared to the precision of the measurements, which implies that most metrics provided unbiased estimates of refractive state for medium and large pupils. Thus a variety of image quality metrics may be used to determine ocular refractive state for monochromatic (635nm) light, thereby achieving accurate results without the need for empirical correction factors.

Purpose: The purpose of the present investigation was to determine objectively the initial magnitude and decay of nearwork-induced transient myopia (NITM), and its potential additivity, following successive but interrupted periods of marked, sustained accommodation at near in asymptomatic young-adult myopic subjects. Methods: Fifteen visually-normal, asymptomatic young adults (ages 18–28 years) were tested with full distance refractive correction. They included nine early-onset (EOM) and six late-onset (LOM) myopic subjects. Accommodation was assessed objectively with a Canon R-1, open-field, infrared auto-refractor under monocular viewing conditions (RE). The distance refractive state was measured immediately before and after a 10 min period of focusing upon a moderate contrast (50%), very near target (12 cm; 8 D) subtending a visual angle of 1°. The task was repeated twice with a 5-min inter-trial rest period of imposed far viewing. NITM was defined as the post-task minus pre-task change in distance refractive state and was determined for each of the three trials. Results: Significant amounts of NITM were generated following nearly each trial in each subject. These ranged from 0.11 to 0.71 D, with a mean of 0.31 D. The group mean NITM was 0.32, 0.29, and 0.31 D for trials 1, 2, and 3, respectively. For the EOMs subgroup, NITM was 0.28, 0.30, and 0.34 D, while for the LOMs subgroup, it was 0.38, 0.29, and 0.26 D, for trials 1, 2, and 3, respectively. Decay of NITM was prolonged in many of the subjects (67%). However, additivity of NITM was not found following the sequences of interrupted near tasks. Conclusions: There was no evidence of NITM additivity following a marked and sustained, but interrupted, near task. Although NITM has been reported to be additive following long periods of uninterrupted and sustained reading at lower dioptric levels, providing rest periods between each near task trial appears to prevent a cumulative effect (i.e. additivity effect).

The depth of focus (DOF) was measured and compared objectively in free space and subjectively in Badal optical space in 10 young adults. The mean total objective DOF was ±0.59 ±0.10 D, with a range from ±0.46 D to ±0.75 D. The mean total subjective DOF was ±0.63 ±0.22 D, with a range from ±0.37 D to ±0.96 D. The objective and subjective DOF values were not significantly different. However, response variability was greater [∼2×] in the subjective test mode. Similarity between the objective and subjective results suggests that blur plays a dominant role in this process, which is in agreement with earlier experiments and model predictions under normal closed-loop viewing conditions.

An empirically based, conceptual model of human blur perception is presented. It incorporates the concepts of blur detection and blur discrimination in depth, and across the central and peripheral retina, in two- and three-dimensional visual space. Key aspects of the model are its dynamic nature, predictability regarding the blur-based depth-ordering of objects, patterns of retinal defocus with far and near viewing, and interactions related to retinal defocus between the central and peripheral retina. Furthermore, a two-dimensional schematic representation of the blur-free region during near viewing is depicted in dioptric space. This model has implications with respect to accommodative control, depth perception, and refractive error development and progression.

Knowledge regarding the amount of blur perceived to be “bothersome” to an individual, namely that which is assumed to be annoying and to adversely affect task performance, remains limited. A Badal optical system was used to measure the blur detection, bothersome blur, and non-resolvable blur dioptric thresholds monocularly either to an isolated 20/50 or 20/200 Snellen E, or to three 20/50 lines of text. Subjects were comprised of 13 visually normal young adults and 3 absolute presbyopes. Cycloplegia was used to paralyze accommodation in the young adults. Within each target type for the young adults, the mean bothersome blur threshold was always significantly larger than that found for blur detection and significantly smaller than that found for non-resolvable blur. Across target types and blur criteria, the bothersome blur thresholds for the isolated 20/50 E (1.02D) and the 20/50 text (1.34D) were not significantly different, although in 12 of the 13 subjects the latter were larger (p

The aim of the current study was to measure the objective depth-of-focus (DOF) of myopes (MYO) in free space and compare them with emmetropic (EMM) and hyperopic (HYP) cohorts. The objective DOF was measured in 35 visually normal, young adults including 16 MYO, 13 EMM, and 6 HYP using the Power Refractor (PR II). The DOF was larger in the MYO and HYP than in the EMM. The larger objective DOF found in the MYO subgroup is in agreement with previous studies assessing the DOF subjectively. This finding is consistent with current thinking that increased amounts of retinal-defocus integrated over extended time may be myopiogenic. In agreement with earlier clinical and computer simulation studies, hyperopes demonstrate a relative resistance to increased retinal defocus.

Purpose.: To report the refractive error difference (RED) between parents and their children, and its risk factors, in a rural area of China. Methods.: Children (6–17 years) and their parents (36.2 ± 4.1 years) from the Handan Offspring Myopia Study (HOMS) were enrolled. Cycloplegic autorefraction (cyclopentolate 1%, Topcon KR8800) of the children and noncycloplegic autorefraction of their parents were assessed. A detailed vision-based questionnaire was also completed. Refractive error difference was defined as the difference between the parental spherical equivalent (SE) and their children's SE. Generational myopic shift was defined as the estimated RED when a child would be 18 years old according to a prediction model. Results.: Three hundred fifty-six pairs of parents and 585 children were enrolled. The RED (median, quartiles) increased from −1.33 (−1.99, −0.98) diopters (D) in children aged 6 to 7 years to 0.81 (−0.16, 2.28) D in children aged 16 to 17 years. The children's SE was predicted to approach the parental SE at 14 years of age. Moreover, the children's estimated myopic shift would be 1.03 D. Multiple linear regression revealed that older children (β = 0.23 D/y, P < 0.0001) and girls (β = 0.24, P = 0.01) tended to have a higher RED. Conclusions.: In this rural Chinese population, the children's refraction was estimated to be similar to the parental refraction at 14 years of age. Moreover, the generational myopic shift was estimated to be approximately 1 D at 18 years of age. These data suggest that the generational difference reflects the increasing prevalence of myopia in the younger generation, which is likely due to changes in environmental exposure.

PURPOSE: To assess the relationship between near work, outdoor activity, and refractive error in schoolchildren in Beijing. METHODS: The Beijing Myopia Progression Study is a hospital-based myopia study, in which 386 students from primary (aged 6 to 12 years) and secondary (aged 13 to 17 years) schools in the inner city of Beijing were enrolled. Cycloplegic refraction and a detailed questionnaire probing near, intermediate, and distance visual activities were completed. RESULTS: Three hundred seventy (95.9%) of 386 students with complete cycloplegic autorefraction and myopia questionnaire data were enrolled in this study. Children with more near work time did not exhibit a significantly more myopic refraction in both the primary and secondary school levels after adjusting for the children's gender, outdoor activity time, and average parental refractive error. A significant association between outdoor activity time (in hours per day) and the children's spherical equivalent (in diopters) was found in the primary school students (β = 0.27, p = 0.03) but not in the secondary school students (β = 0.04, p = 0.70) after adjusting for similar confounders. The time spent on outdoor sports and outdoor leisure in the primary school students was also significantly associated with the children's spherical equivalent (β = 0.46, p = 0.04 and β = 0.31, p = 0.02, respectively). Primary school students with more time outdoors exhibited relatively less myopic refraction than their peers (ptrend = 0.0003), but this relation was not demonstrated in the secondary school children (ptrend = 0.53) after adjusting for similar confounders. CONCLUSIONS: Higher levels of outdoor activity were associated with less myopic refraction in primary school students in the inner city of Beijing. Near work activity was not found to be associated with refraction at either school level. Language: en

Background Traditional Chinese eye exercises of acupoints involve acupoint self-massage. These have been advocated as a compulsory measure to reduce ocular fatigue, as well as to retard the development of myopia, among Chinese school children. This study evaluated the impact of these eye exercises among Chinese urban children. Methods 409 children (195 males, 47.7%), aged 11.1 ± 3.2 (range 6–17) years, from the Beijing Myopia Progression Study (BMPS) were recruited. All had completed the eye exercise questionnaire, the convergence insufficiency symptom survey (CISS), and a cycloplegic autorefraction. Among these, 395 (96.6%) performed the eye exercises of acupoints. Multiple logistic regressions for myopia and multiple linear regressions for the CISS score (after adjusting for age, gender, average parental refractive error, and time spent doing near work and outdoor activity) for the different items of the eye exercises questionnaire were performed. Results Only the univariate odds ratio (95% confidence interval) for “seriousness of attitude” towards performing the eye exercises of acupoints (0.51, 0.33-0.78) showed a protective effect towards myopia. However, none of the odds ratios were significant after adjusting for the confounding factors. The univariate and multiple β coefficients for the CISS score were -2.47 (p = 0.002) and -1.65 (p = 0.039), -3.57 (p = 0.002) and -2.35 (p = 0.042), and -2.40 (p = 0.003) and -2.29 (p = 0.004), for attitude, speed of exercise, and acquaintance with acupoints, respectively, which were all significant. Conclusions The traditional Chinese eye exercises of acupoints appeared to have a modest effect on relieving near vision symptoms among Chinese urban children aged 6 to 17 years. However, no remarkable effect on reducing myopia was observed.

Purpose. To assess changes in the nearwork-induced transient myopia parameters of initial magnitude and its decay duration, as well as accuracy of the near accommodative steady-state response and clinically based accommodative facility, after 6 weeks of home-based accommodative training in asymptomatic myopes. Methods. Ten young adult, progressing myopes participated in the study. The experimental paradigm consisted of a baseline session and two follow-up sessions at the end of the third and sixth weeks of training. At the first session, baseline refractive state and selected accommodative functions were assessed. Measurements were repeated at the two follow-up sessions. Home-based vision training included accommodative flippers (±2 D) at near, Hart chart at distance (6 m) and near (40 cm), and prism flipper (6 pd) training at near (40 cm), for a total of 20 minutes a day performed 5 days a week for 6 weeks. Results. Several dynamic accommodative response functions improved significantly with training. Lens flipper rate increased significantly from 11 to 16 cpm in the OD (p = 0.04), 11 to 19 cpm in the OS (p = 0.03), and 8 to 11 cpm in the OU (p = 0.03). Hart chart rate increased significantly from 22 to 33 cpm in the OD (p = 0.01) and from 22 to 31 cpm in the OS (p = 0.02). There was a significant negative correlation between lens flipper rate and nearwork-induced transient myopia decay duration after training (p = 0.02) with binocular viewing. Conclusions. Training of the accommodative system in these progressing myopes resulted in improved dynamics in both laboratory and clinical measures. This is consistent with earlier reports in the literature of improvement in symptomatic myopic subjects.

PURPOSE: Recent experiments have suggested transient changes in corneal optics after short durations of reading. This study investigated an interrupted 1-hour period of reading on corneal topography in a sample of young myopic and emmetropic adults. METHODS: Ten myopic and 9 emmetropic young adult subjects were recruited for the study. They read adult-level text binocularly at 40 cm with approximately 30 degree downward gaze for 1 hour, with distance correction in place. Orbscan II corneal topography was performed at baseline and 5, 15, 30, and 60 minutes after reading during 1 test session to assess for changes in corneal power, aberrations, and thickness. RESULTS: Myopes exhibited greater corneal power and spherical aberration than emmetropes both before and after reading. Increased corneal higher-order aberrations (at baseline only) and thickness (superior position only) were observed in myopes versus emmetropes. CONCLUSIONS: Several corneal parameters differed in the myopes after reading as compared with emmetropes. Differences in corneal parameters were smaller in this study than found in earlier studies, perhaps because of the interrupted nature of the task in the former versus the continuous nature in the latter.

The depth-of-focus (DOF) plays a major role in accommodative control. It provides a neurological tolerance for retinal defocus and the perception of blur. Hence, the DOF has been an important component in bioengineering models of the accommodative system, but with its model-based control function limited to the fovea. However, new studies have demonstrated the influence of the near retinal periphery on the DOF: with increased target extent, the DOF increases. Thus, the blur control derived from the combined fovea and near retinal periphery should be incorporated into future models of accommodation.

Determining the depth-of-focus (DOF) objectively in free space is important, as this provides information regarding the range of clear vision under more natural viewing conditions in which target blur, size, and proximal information, as well as other monocular depth cues, are present.The DOF was assessed objectively in free space in young adults [n=20, ages 24.9+/-3.1years: myopes (n=14), emmetropes (n=5), hyperope (n=1)] by monitoring accommodation continuously using the commercially available Power Refractor II (PR II) under monocular viewing conditions. A high-contrast target ( approximately 83%) subtending a mean visual angle of 2.3 deg was placed on an optical bench at 25 cm (4 D) along the line-of-sight of the viewing right eye and was displaced slowly ( approximately 0.1-0.15 D/s) proximally and distally. This target provided blur, size, and proximal information, and other depth cues, as normally found in free space. The first consistent change in steady-state accommodative baseline level reflected one edge of the DOF. The mean dioptric difference between these distal and proximal endpoints was averaged, and this represented the total objective DOF.The group mean total objective DOF (n=20) was +/-0.61+/-0.09 D, with a range from +/-0.46 D to +/-0.81 D. Repeatability was excellent.A technique was developed and tested to measure the DOF in free space objectively. Further development of this technique will allow the assessment of blur perception under more complex natural viewing conditions simulating the everyday environment.

PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15% of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.

Background The aim of the present study was to investigate the effect of near-work on lower and higher-order aberrations, and its progression over a 9-month period during the school year. Methods Data from 24 young-adult myopic eyes, and 24 non-myopic eyes were used in this investigation. The lower-order aberrations, coma, spherical aberration (SA), and total root mean square (RMS) of higher order aberrations (total HOA) were measured using an open-field iTrace aberrometer, at both the initial baseline evaluation, and then at the follow-up visits over a 9-month period. Pupil size of 4 mm was used for the aberration measurements. Results The group mean (SD) of the subjects (mean age: 23.6 +/- 3.4 years) at the initial and follow-up visit was 0.47D (0.47D) and 0.31D (0.41D), in the non-myopes and -3.58D (2.08D) and -3.86D (2.14D) in the myopes, respectively. Significant increases in myopic refraction were observed. The group mean (SD) total HOA at the initial and final visit was 0.12 (0.08) and 0.11 (0.06) microns, in the non-myopes, and 0.15 (0.08) and 0.15 (0.08) microns, in the myopes, respectively. The group mean RMS of the coma at the initial and final visit was 0.06 (0.04) and 0.07 (0.05), in the non-myopes, and 0.08 (0.06) and 0.09 (0.06) microns, in the myopes, respectively. The group mean SA of the subjects at the initial and last visit was 0.04 (0.04) and 0.03 (0.03), in the non-myopes, and 0.04 (0.04) and 0.04 (0.04) microns, in the myopes, respectively. Conclusions There was a significant difference in myopic refraction, over the 9-month assessment period. However, no significant difference in total HOA, SA, and coma between the initial and follow-up visits in both the myopes and the non-myopes was observed.