初发近视儿童非睫状肌麻痹主觉验光的准确性评估

目的：观察9～13 岁初发近视儿童睫状肌麻痹前后主觉验光是否存在差异并分析相关影响因素,为临床上近视儿童的验光方法的选择提供参考依据。方法：前瞻性临床研究。收集2017 年5-9 月在温州医科大学附属眼视光医院就诊的近视儿童90 例,所有受检者行非睫状肌麻痹主觉验光,然后测量并记录其隐斜量、正负相对调节力、调节反应值。之后用1%盐酸环喷托酯滴眼液点眼3次,45 min后测量电脑验光并复测主觉验光。均取右眼数据用于统计,采用方差分析和多元线性回归进行统计学分析。结果：非睫状肌麻痹主觉验光屈光度为（-1.09±0.30）D,睫状肌麻痹后电脑验光屈光度为（-1.27±0.40）D,睫状肌麻痹后主觉验光屈光度为（-1.09±0.33）D,睫状肌麻痹前、后主觉验光差异无统计学意义（P>0.05）。睫状肌麻痹后电脑验光柱镜度高于主觉验光（P<0.001）,而球镜度差异无统计学意义（P>0.05）。多元线性回归分析发现睫状肌麻痹前、后屈光度差值不受年龄（β=0.044,P=0.699）、屈光度（β=0.091,P=0.430）、隐斜（β=-0.059,P=0.599）、调节滞后量（β=-0.064,P=0.576）、正相对调节能力（β=0.043,P=0.709）等因素影响。结论：在排除调节或集合功能异常的情况下,大部分9～13岁初发性近视儿童可采用非睫状肌麻痹主觉验光获得比较准确的屈光度。     

Differences in Prevalence of Refractive Errors in Young Asian Males in Singapore between 1996–1997 and 2009–2010

Purpose: To determine the differences in prevalence rates of refractive errors in young Singaporean males over a 13-year period between 1996–1997 and 2009–2010

Methods: Non-cycloplegic autorefraction data were obtained in a survey of 15,085 young male subjects (mean age 19.5?±?1.4 years, range 16–25 years) in 1996–1997 using a Nikon NRK-8000 autorefractor. A second survey of 28,908 male subjects (mean age 19.8?±?1.2 years, range 17–29 years) was conducted in 2009–2010 using a Huvitz MRK-3100 autorefractor.

Results: The overall prevalence of myopia (spherical equivalent, SEq, worse than ?0.5 diopters, D) was similar in 2009–2010 (81.6%) and 1996–1997 (79.2%; odds ratio 1.38, 95% confidence interval 1.31–1.46; p?p?p?Conclusions: Our results show that the prevalence of myopia and high myopia remained high and the prevalence of astigmatism increased in young male adults in Singapore over a 13-year period after controlling for age, education and ethnicity.     

广州市荔湾区学龄儿童屈光不正患病率的现况调查

目的 探讨广州市荔湾区5～15岁儿童的屈光不正患病率情况.方法 采用人群为基础的横断面调查方法.在2002年10月至2003年1月期间,中山大学巾山眼科中心对广州市荔湾区居住的全部5～15岁儿童,通过随机整群抽样和逐户登记确定样本与受检对象,在71个学校和19个社区检查点进行检查,眼部榆查包括视力、眼球运动、散瞳检影验光、自动验光、外眼、眼前段、屈光间质及眼底检查.屈光不正与儿童的年龄、性别及家长教育程度的关系采用多元回归模型进行分析.结果 在登记的5053名儿童中,实际检查4364人,受检率为86.4%.以等效球镜-0.50 D以下作为界定,近视的患病率为35.1%(95%可信区间:33.2%～36.9%),患病率从5岁的3.3%增加到15岁时的73.1%(根据检影验光);女性儿童具有较高的患病率,调整比数比为1.29(95%可信区间:1.11～1.51);以等效球镜+2.00 D以上作为界定,远视患病率为5.8%(95%可信区间:5.3%～6.3%),从5岁时16.7%减少到15岁时低于1.0%.散光(柱镜屈光度≥0.75 D)的患病率在视网膜检影法为33.6%,而在自动验光法为42.7%.Logistie回归模型显示近视与年龄(OR=1.52,95%可信区间:1.48～1.56)、女性(OR=1.29,95%可信区间:1.11～1.51)和父母教育程度(OR=1.22,95%可信区间:1.05～1.42)有关.结论 广州市荔湾区学龄儿童具有较高的近视患病率,近视已经成为重要的公共卫生问题,提高儿童屈光矫正的覆盖率和质量足当前的主要挑战.     

Factors related to the progression of myopia in Singaporean children.

PURPOSE: To examine the possible factors related to the progression of myopia in Singapore children. METHODS: One hundred fifty-three Singapore children aged 6 to 12 years were recruited to participate in a concurrent cohort study of the risk factors for the progression of myopia. Socioeconomic status, outdoor activity, and near-work activity were documented in a face-to-face clinic interview. The changes in cycloplegic subjective refraction and autorefraction were ascertained with the use of a Nidek ARK 900 over a 2-year period. RESULTS: The average rate of progression of myopia as measured by subjective refraction was -0.59 D per year (95% confidence interval -0.52, -0.66). Younger children and children who were more myopic at the beginning (refractive error worse than -2.0 D) of the study had higher myopia progression rates. CONCLUSIONS: Myopia progression was faster for younger children and for children who had more severe myopia at baseline. Socioeconomic status and near-work activity were not related to myopia progression.     

Prevalence and characteristics of peripheral retinal degeneration in Chinese adults with high myopia: a cross-sectional prevalence survey.

PURPOSE: The purpose of this study was to study the prevalence of peripheral retinal findings in adult Chinese patients with high myopia (refraction < or = -6.00 D) and to investigate the correlation between the retinal lesions and the severity of myopia or axial length. METHODS: A cross-sectional prevalence survey screening was conducted in high ethnic Chinese myopes with refractions equal to or less than -6.00 D. The examinations included cycloplegic refraction, A and B scan ultrasonography, and retinal examinations by indirect ophthalmoscopy with scleral indentation and Goldmann three-mirror contact lens examination. RESULTS: Two hundred thirteen eyes in 213 patients with a mean refraction of -10.10 +/- 4.23 D (range = -6.00 to -27.00 D) were examined. The mean axial length was 26.69 +/- 1.68 mm (range = 25.18-33.62 mm) and the mean age was 33.5 +/- 10.6 years (range = 18-73 years). The most common peripheral retinal finding was pigmentary degeneration (51.2%), followed by lattice degeneration in 12.2% and retinal holes in 7.5% of eyes. A positive correlation was noted between axial length and the lesions of pigmentary degeneration and pavingstone degeneration. The prevalence of retinal holes was 6.4% and 30.0% in eyes with axial length of < 30 mm and > or = 30 mm, respectively (chi-squared test, p = 0.006). CONCLUSION: A high prevalence of peripheral retinal degenerations was found in adult Chinese high myopes. The presence of retinal holes was positively correlated with very high myopia of an axial length of > or = 30 mm.     

Refractive error and visual impairment in urban children in southern china

PURPOSE: To assess the prevalence of refractive error and visual impairment in school-age children in a metropolitan area of southern China. METHODS: Random selection of geographically defined clusters was used to identify children 5 to 15 years of age in Guangzhou. Children in 22 clusters were enumerated through a door-to-door survey and examined in 71 schools and 19 community facilities from October 2002 to January 2003. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy, and autorefraction under cycloplegia and examination of the external eye, anterior segment, media, and fundus. RESULTS: A total of 5053 children living in 4814 households were enumerated, and 4364 (86.4%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity 20/40 or worse in the better eye was 22.3%, 10.3%, and 0.62%, respectively. Refractive error was the cause in 94.9% of the 2335 eyes with reduced vision, amblyopia in 1.9%, other causes in 0.4%, and unexplained causes in the remaining 2.8%. External and anterior segment abnormalities were seen in 1496 (34.3%) children, mainly minor conjunctival abnormalities. Media and fundus abnormalities were observed in 32 (0.73%) children. Myopia (spherical equivalent of at least -0.50 D in either eye) measured with retinoscopy affected 73.1% of children 15 years of age, 78.4% with autorefraction. The prevalence of myopia was 3.3% in 5-year-olds with retinoscopy and 5.7% with autorefraction. Females had a significantly higher risk of myopia. Hyperopia (+2.00 D or more) measured with retinoscopy was present in 16.7% of 5-year-olds, 17.0% with autorefraction. The prevalence of hyperopia was below 1% in 15-year-olds, with both methods. Astigmatism (cylinder of > or = 0.75 D) was present in 33.6% of children with retinoscopy and in 42.7% with autorefraction. CONCLUSIONS: The prevalence of reduced vision because of myopia is high in school-age children living in metropolitan Guangzhou, representing an important public health problem. One third of these children do not have the necessary corrective spectacles. Effective strategies are needed to eliminate this easily treated cause of significant visual impairment.     

Validity of noncycloplegic refraction in the assessment of refractive errors: the Tehran Eye Study

Purpose: To determine the sensitivity and specificity of noncycloplegic autorefraction for determining refractive status compared to cycloplegic autorefraction. Methods: The target population was noninstitutionalized citizens of all ages, residing in Tehran in 2002, selected through stratified cluster sampling. From 6497 eligible residents, 70.3% participated in the study, from August to November 2002. Here, we report data on 3501 people over the age of 5 years who had autorefraction with and without cycloplegia (two drops of cyclopentolate 1.0% 5 min apart, with autorefraction 25 min after the second drop). Results: Overall, the sensitivity of noncycloplegic autorefraction for myopia was 99%, but the specificity was only 80.4%. In contrast, the sensitivity for hyperopia was only 47.9%, but the specificity was 99.4%. At all ages, noncycloplegic autorefraction overestimated myopia and underestimated hyperopia. Overestimation of myopia was highest in the 21–30 and 31–40 year groups. Underestimation of hyperopia was high up to the age of 50 (20–40%), but decreased with age, to about 8% after the age of 50, down to almost 0% after 70. The difference in mean spherical equivalent with and without cycloplegia fell from 0.71 dioptres (D) in the 5–10 age group to 0.14D in those over 70. Conclusion: Use of noncycloplegic autorefraction in epidemiological studies leads to considerable errors relative to cycloplegic measurements, except in those over 50–60. The difference between cycloplegic and noncycloplegic measurements varies with age and cycloplegic refractive category, and there is considerable individual variation, ruling out adjusting noncycloplegic measurements to obtain accurate cycloplegic refractions.     

Refractive errors in an elderly Chinese population in Taiwan: the Shihpai Eye Study

PURPOSE: Few epidemiologic data are available on refractive status in elderly Asians. The purpose of the study was to determine prevalence and risk factors associated with refractive errors in a metropolitan elderly Chinese population in Taiwan. METHODS: A population-based survey was conducted in the Shihpai district of Taipei, Taiwan. A total of 2045 residents aged 65 years or more were randomly selected and invited to complete a comprehensive questionnaire and undertake a detailed ocular examination, including best corrected visual acuity and measurements of refractive error, using autorefraction. Of the subjects, 1361 (66.6%) participated in the ocular examination. Spherical equivalent (SE) was calculated in diopters (D), and data from right eyes were reported. RESULTS: The age- and sex-adjusted prevalence rates were determined for myopia (SE<-0.5 D, 19.4%; SE<-1.0 D, 14.5%), high myopia (SE<-6.0 D, 2.4%), hyperopia (SE>+0.5 D, 59.0%; SE>+1.0 D, 44.2%), astigmatism (cylinder<-0.5 D, 74.0%; cylinder<-1.0 D, 45.3%), and anisometropia (SE difference between right and left eyes>0.5 D, 45.2%; SE difference>1.0 D, 21.8%). The prevalence of myopia, astigmatism, and anisometropia significantly increased with age (all P<0.01). The prevalence of hyperopia tended to decrease with age. There was no gender difference in prevalence rates in any type of refractive error, except that women had a higher rate of hyperopia (SE>+1.0 D) than men (P=0.004). Multivariate regression analysis showed that myopia was weakly associated with higher educational level. The severity of lens nuclear opacity was positively associated with the rates of myopia and negatively associated with the rates of hyperopia. CONCLUSIONS: The prevalence of myopia in this elderly Chinese population is not much higher than in similarly aged elderly white populations, compared with a much greater difference in prevalence among younger Chinese versus white people. This suggests that changing environmental factors may account for the increased prevalence of myopia in younger cohorts of Chinese.     

Factors associated with high myopia after 7 years of follow-up in the Correction of Myopia Evaluation Trial (COMET) Cohort

PURPOSE: To evaluate factors associated with the development of high myopia (worse than -6.00 D) over 7 years of follow-up in the COMET cohort. METHODS: COMET enrolled 469 ethnically diverse children (6-11 years) with myopia between -1.25 and -4.50 D. They were randomized to either progressive addition lenses (PALs) or single vision lenses (SVLs), and followed for 5 years in their original lens assignment and 2 additional years wearing either spectacles (PALs or SVLs) or contact lenses. Refractive error was measured annually by cycloplegic autorefraction and axial length by A-Scan ultrasonography. Myopia for each child was defined as the mean spherical equivalent refractive error (SER) of the 2 eyes. Analyses were based on 7 years of follow-up. Time to high myopia was analyzed by Cox proportional hazard models and linear regression. Parental refraction data were available from 240 COMET subjects. RESULTS: Younger (6-7 years) versus older (11 years) age at baseline was a significant risk factor (adjusted hazard ratio (HR) = 6.6, 95% CI = 3.4, 12.7) for having high myopia within 7 years. More (SER from -2.26 to -4.50 D) vs. less (SER from -1.25 to -2.25 D) baseline myopia was also a significant risk factor for high myopia at 7 years (adjusted HR = 7.4, 95% CI = 4.4, 12.4). Gender, ethnicity, and treatment assignment were not associated with the risk of high myopia within 7 years. Increased number of myopic parents was associated with a significant risk of high myopia in the children (p = 0.008). CONCLUSIONS: Children who developed high myopia during 7 years of follow-up were younger and had more myopia at baseline. They also were more likely to have two myopic parents. These children may be at greater risk for sight-threatening conditions later in life.     

A pilot study of the precision of digital intraocular pressure measurement during vitrectomy

AIM: To evaluate the precision of digital intraocular pressure (IOP) measurement in silicone oil (SO) filled eyes during vitrectomy. METHODS: This is a retrospective, single-blind study. Patients who were diagnosed with retinal detachment and scheduled for vitrectomy with SO injection were consecutively enrolled. During the vitrectomy, IOP was digitally measured and then by a rebound tonometer (IcarePRO). The rebound tonometer readings were masked to the surgeons. The digitally measured IOP and that of rebound tonometer were compared, and the inter-methods agreement was assessed. The absolute deviation in IOP values between these two methods (?IOP) was also calculated, and correlations between ?IOP and refractive status, lens status and levels of surgeons’ experience were analyzed. RESULTS: A total of 131 patients (131 eyes) were recruited, with a mean age of 51.0±16.1y. There was no significant difference in IOPs between digital measurement and the rebound tonometer (15.6±4.3 vs 15.7±5.1 mm Hg; t=0.406, P=0.686). Intraclass correlation coefficients (ICC) analysis indicated a strong correlation between these two measurements (ICC=0.830, P<0.001). The mean ?IOP was 2.0±1.9 mm Hg (range: 0-12.8 mm Hg), with 98 eyes (74.8%) had the ?IOP within 3 mm Hg. ?IOP was found to be negatively correlated with levels of surgeons’ experience (r=-0.183; P=0.037), but not with the refractive status or lens status of the patients (both P>0.05). CONCLUSION: For experienced surgeons, the digital IOP measurement may be an acceptable technique for IOP measurement in SO filled eyes during vitrectomy. However, its use by inexperienced surgeons should be taken with caution.     

Myopia prevalence in Chinese-Canadian children in an optometric practice.

PURPOSE: The high prevalence of myopia in Chinese children living in urban East Asian countries such as Hong Kong, Taiwan, and China has been well documented. However, it is not clear whether the prevalence of myopia would be similarly high for this group of children if they were living in a Western country. This study aims to determine the prevalence and progression of myopia in ethnic Chinese children living in Canada. METHODS: Right eye refraction data of Chinese-Canadian children aged 6 to 12 years were collated from the 2003 clinical records of an optometric practice in Mississauga, Ontario, Canada. Myopia was defined as a spherical equivalent refraction (SER) equal or less than -0.50 D. The prevalence of myopia and refractive error distribution in children of different ages and the magnitude of refractive error shifts over the preceding 8 years were determined. Data were adjusted for potential biases in the clinic sample. A questionnaire was administered to 300 Chinese and 300 Caucasian children randomly selected from the clinic records to study lifestyle issues that may impact on myopia development. RESULTS: Optometric records of 1468 children were analyzed (729 boys and 739 girls). The clinic bias adjusted prevalence of myopia increased from 22.4% at age 6 to 64.1% at age 12 and concurrently the portion of the children that were emmetropic (refraction between -0.25 and +0.75 D) decreased (68.6% at 6 years to 27.2% at 12 years). The highest incidence of myopia for both girls ( approximately 35%) and boys ( approximately 25%) occurred at 9 and 10 years of age. The average annual refractive shift for all children was -0.52+/-0.42 D and -0.90+/-0.40 D for just myopic children. The questionnaire revealed that these Chinese-Canadian children spent a greater amount of time performing near work and less time outdoors than did Caucasian-Canadian children. CONCLUSIONS: Ethnic Chinese children living in Canada develop myopia comparable in prevalence and magnitude to those living in urban East Asian countries. Recent migration of the children and their families to Canada does not appear to lower their myopia risk.     

Incidence and progression of myopia in Singaporean school children

PURPOSE: To determine the incidence and progression rates of myopia in young Singaporean children. METHODS: A prospective cohort study, the Singapore Cohort Study of the Risk Factors for Myopia (SCORM), was conducted in two schools in Singapore (1999-2002). Children aged 7 to 9 years (n=981) were followed up over a 3-year period. Cycloplegic autorefraction and biometry parameter measures were performed annually, according to the same protocol. RESULTS: The 3-year cumulative incidence rates were 47.7% (95% confidence interval [CI]: 42.2-53.3), 38.4% (95% CI: 31.4-45.4), and 32.4% (95% CI: 21.8-43.1) for 7-, 8-, and 9-year-old children, respectively. The 3-year cumulative incidence rates were higher in Chinese (49.5% vs. 27.2%) and in 7-year-old compared with 9-year-old children at baseline (47.7% vs. 32.4%), though the latter relationship was of borderline significance after adjustment for race, gender, amount of reading (books/week), and parental myopia (P=0.057). Premyopic children with greater axial lengths, vitreous chamber depths, and thinner lenses were more prone to the development of myopia, after controlling for age, gender, race, reading, and parental myopia. The 3-year mean cumulative myopia progression rates were -2.40 D (95% CI: -2.57 to -2.22) in 7-year-old myopic children, -1.97 (95% CI: -2.16 to -1.78) in 8-year-olds, and -1.71 (95% CI: -1.98 to -1.44) in 9-year-olds. CONCLUSIONS: Both the incidence and progression rates of myopia are high in Singaporean children.     

Astigmatism in Chinese preschool children: prevalence, change, and effect on refractive development

AIM: To study the prevalence, type, and progression of astigmatism in Chinese preschool children, and its effect on refractive development. METHODS: A cross sectional study of preschool children was carried out in two randomly selected kindergartens. A cohort study was performed on a subset of children, five years after initial examination. Refractive error (measured by cycloplegic autorefraction) and axial ocular dimensions (measured by ultrasonography) were the main study outcomes. RESULTS: 522 children participated in the study; the mean age was 55.7 months (SD 10.9; range 27 to 77). Mean cylinder reading was -0.65 D (SD 0.58; range 0.00 to -4.75), and with the rule astigmatism was predominant (53%). In the 108 children studied longitudinally, the mean cylinder reading reduced from -0.62 D to -0.50 D (p = 0.019). The presence of astigmatism in initial examination predisposed the eyes towards greater myopisation (p<0.001). In addition, children with increased astigmatism had greater myopic progression (p<0.001) and axial length growth (p = 0.002). CONCLUSIONS: This study reports a high prevalence of astigmatism in Chinese preschool children. The presence of astigmatism, and particularly with increasing astigmatism, appears to predispose the children to progressive myopia. Further studies are warranted.     

Post-cycloplegia myopic shift in an older population

PURPOSE: To demonstrate that use of a mydriatic agent remains a significant confounder in autorefraction of the presbyopic population. METHODS: The pre- and post-cycloplegic autorefraction results of 37 subjects over 50 years of age were measured using a Humphrey-598 autorefractor. The results of both eyes were included in a multivariate regression analysis. RESULTS: The average age of the patient sample was 63.4 years. The mean spherical equivalent (SEQ) shifts for the hyperopic, myopic, pseudophakic, and emmetropic eyes were -0.53 D (95% CI -0.77 D to -0.39 D; p < 0.001), -0.38 D (95%CI -0.81 D to +0.04 D; p = 0.077), -0.49 D (95% CI -0.78 D to -0.20 D; p = 0.001), and -0.35 D (95% CI -0.59 D to -0.11 D; p = 0.004), respectively. CONCLUSION: Cyclopleged autorefraction in the presbyopic population is associated with a myopic shift that can potentially lead to overestimation of myopic prevalence. This is an important factor in comparing population studies where cyclogleged autorefraction is used in contrast to non-cyclopleged autorefraction and subjective refraction.     

Prevalence of refractive errors in teenage high school students in Singapore

We aimed to study the prevalence of refractive conditions in Singapore teenagers. Grade 9 and 10 students (n = 946) aged 15-19 years from two secondary schools in Singapore were recruited. The refractive errors of the students' eyes were measured using non-cycloplegic autorefraction. Sociodemographic data and information on risk factors for myopia (such as reading and writing) were also obtained using an interviewer-administered questionnaire. The prevalence of refractive conditions was found to be: myopia [spherical equivalent (SE) at least -0.50 D] - 73.9%, hyperopia (SE at least +0.50 D) - 1.5%, astigmatism (cylinder at least -0.50 D) - 58.7% and anisometropia (SE difference at least 1.00 D) - 11.2%. After adjusting for age and gender, currently doing more than 20.5 h of reading and writing a week was found to be positively associated with myopia [odds ratio 1.12 (95% CI 1.04-1.20, p = 0.003)], as was reading and writing at a close distance and a better educational stream. The prevalence of myopia (73.9%) in Singapore teenagers is high. Current reading and writing habits, reading at close distances and a better educational stream are possible risk factors for myopia.     

Anisometropia prevalence in a highly astigmatic school-aged population

PURPOSE: To describe prevalence of anisometropia, defined in terms of both sphere and cylinder, examined cross-sectionally, in school-aged members of a Native American tribe with a high prevalence of astigmatism. METHODS: Cycloplegic autorefraction measurements, confirmed by retinoscopy and, when possible, by subjective refraction were obtained from 1041 Tohono O'odham children, 4 to 13 years of age. RESULTS: Astigmatism > or =1.00 diopter (D) was present in one or both eyes of 462 children (44.4%). Anisometropia > or =1.00 D spherical equivalent (SE) was found in 70 children (6.7%), and anisometropia > or =1.00 D cylinder was found in 156 children (15.0%). Prevalence of anisometropia did not vary significantly with age or gender. Overall prevalence of significant anisometropia was 18.1% for a difference between eyes > or =1.00 D SE or cylinder. Vector analysis of between-eye differences showed a prevalence of significant anisometropia of 25.3% for one type of vector notation (difference between eyes > or =1.00 D for M and/or > or =0.50 D for J0 or J45), and 16.2% for a second type of vector notation (between-eye vector dioptric difference > or =1.41). CONCLUSIONS: Prevalence of SE anisometropia is similar to that reported for other school-aged populations. However, prevalence of astigmatic anisometropia is higher than that reported for other school-aged populations.     

Baseline refractive and ocular component measures of children enrolled in the correction of myopia evaluation trial (COMET)

PURPOSE: To describe baseline refractive and ocular component measures in children with myopia enrolled in the Correction of Myopia Evaluation Trial (COMET). COMET is a multicenter, randomized clinical trial to evaluate whether progressive-addition lenses slow the progression of juvenile-onset myopia compared with single-vision lenses. METHODS: Four hundred sixty-nine children with myopia between -1.25 and -4.50 D spherical equivalent and without eye or systemic conditions known to affect refractive development were recruited from four geographically and ethnically diverse communities in the United States. Their ages were 6 to 11 years inclusive, and 52% were girls. The main outcome measure for the overall trial is progression of myopia determined by cycloplegic autorefraction after inducement of cycloplegia with 2 drops of 1% tropicamide. Axial length, the secondary outcome measure, was assessed by ultrasonography. The distance correction was determined by subjective methods before cycloplegia, with noncycloplegic autorefraction values as the starting point. RESULTS: Because data were similar in both eyes, they are reported for the right eye only. The mean spherical equivalent measured by cycloplegic autorefraction was -2.38 +/- 0.81 D. Young children had significantly less myopia than older children (P = 0.03), but the amount of myopia did not differ by gender or ethnicity. Mean axial dimensions were 4.0 +/- 0.2 mm (anterior chamber), 3.4 +/- 0.2 mm (lens), 16.8 +/- 0.7 mm (vitreous chamber), and 24.1 +/- 0.7 mm (axial length). Girls' eyes had significantly shorter axial length than boys' (P < 0.0001). Mean corneal radii were 7.73 +/- 0.25 mm (horizontal) and 7.59 +/- 0.24 mm (vertical). Ninety-five percent of the eyes had a ratio of axial length to corneal radius higher than 3.0. CONCLUSIONS: These baseline measures provide cross-sectional data on a large group of ethnically diverse children with myopia. Refractive and axial component dimensions are consistent with data in other studies showing that myopic eyes have longer vitreous chambers than emmetropic eyes. The measures reported herein will serve as a basis for examining changes that occur over a minimum of 3 years of follow-up of children enrolled in COMET.     

A cohort study of incident myopia in Singaporean children

PURPOSE: To determine the risk factors of incident myopia in a school-based cohort study in Singaporean children. METHODS: A 3-year prospective cohort study was conducted in Singaporean school children aged 7 to 9 years in three schools at entry. Chinese children without myopia at baseline (n = 994) were included in the analysis. The main outcome was incident myopia, defined as spherical equivalent (SE) at least -0.75 D based on cycloplegic autorefraction. Other definitions of incident myopia, at least -0.5 D and at least -1.0 D, were also assessed. RESULTS: After controlling for school, age, gender, income, reading in books per week and intelligence quotient (IQ) test scores, we found the relative risk (RR) of incident myopia defined as -0.75 D to be 1.55 (95% confidence interval [CI] 1.18-2.04) for two versus no myopic parents. The multivariate RR of myopia for IQ in the third versus first tertile was 1.50 (95% CI, 1.19-1.89). However, the RR of incident myopia was 1.01 (95% CI, 0.97-1.05) for every unit increase in books read per week. Similar results were obtained with definitions of -0.5 and -1.0 D for incident myopia. CONCLUSIONS: These data provide new prospective evidence of essential links between parental myopia, IQ scores and subsequent myopia development. However, reading in books per week was not associated with incident myopia.     

2018～2020年成都市新都区小学生近视流行病学研究

目的:观察新冠疫情居家隔离期(2020-01/05)前后成都市新都区小学生的近视流行病学特点。方法:横断面研究。采用随机分层整群抽样的调查方法,连续3a(2018~2020年)抽取成都市新都区4所小学的一年级到六年级学生(6~13岁),每个年级3个班共10153人,对纳入对象行视力检查及电脑验光,视力<5.0则进行散瞳验光,记录等效球镜度(SE),并计算各年龄组近视患病率。采用卡方检验比较不同年度近视患病率的差异,单因素方差分析比较不同年度SE的差异。结果:2018、2019、2020年近视患病率分别为35.98%、36.29%、42.52%(χ²=39.374,P<0.001)。6~9岁组学生2020年近视患病率明显提高(P<0.01),分别为2019年的2.20倍(6岁)、2.08倍(7岁)、1.36倍(8岁)、1.24倍(9岁)。6~9岁组学生2020年SE出现明显近视化(P<0.05),比2019年分别增长-0.34±0.76D(6岁)、-0.28±0.84D(7岁)、-0.29±1.41D(8岁)、-0.18±1.35D(9岁)。10~13岁组学生2018~2020年近视患病率及SE基本保持稳定(P>0.05)。结论:新冠疫情居家隔离期后,6~9岁学生的近视进展明显加快,应更加重视6~9岁近视防控的窗口期。