PurposeTo examine the associations of near work related parameters with spherical equivalent refraction and axial length in Chinese children.MethodsA total of 1770 grade 7 students with mean age of 12.7 years were examined with cycloplegic autorefraction and axial length. Questions were asked regarding time spent in near work and outdoors per day, and near work related parameters.ResultsMultivariate models revealed the following associations with greater odds of myopia: continuous reading (> 45min), odds ratio [OR], 1.4; 95% confidence interval [CI], 1.1-1.8; close television viewing distance (≤ 3m), OR, 1.7; 95% CI, 1.2-2.3; head tilt when writing, OR, 1.3; 95% CI, 1.1-1.7, and desk lighting using fluorescent vs. incandescent lamp, OR, 1.5; 95% CI, 1.2-2.0. These factors, together with close reading distance and close nib-to-fingertip distance were significantly associated with greater myopia (P<0.01). Among near work activities, only reading more books for pleasure was significantly associated with greater myopia (P=0.03). Television viewing distance (≤ 3 m), fluorescent desk light, close reading distance (≤20 cm) and close nib-to-fingertip distance (≤ 2 cm) were significantly associated with longer axial length (P<0.01). Reading distance, desk light, and reading books for pleasure had significant interaction effects with parental myopia.ConclusionsContinuous reading, close distances of reading, television viewing and nib-to-fingertip, head tilt when writing, reading more books for pleasure and use of fluorescent desk light were significantly associated with myopia in 12-year-old Chinese children, which indicates that visual behaviors and environments may be important factors mediating the effects of near work on myopia.

The ACES is the first large-scale cohort study in China with baseline response rates over 90%. Continuous documentation of changes and risk factors of refractive errors in these cohorts would provide new insights into myopia control in school-aged children.

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PURPOSE.To test the hypothesis that relative peripheral hyperopia predicts development and progression of myopia. METHODS.Refraction along the horizontal visual field was measured under cycloplegia at visual field angles of 08, 6158, and 6308 at baseline, 1 and 2 years in over 1700 initially 7-year-old Chinese children, and at baseline and 1 year in over 1000 initially 14-year olds. One refraction classification for central refraction was ''nonmyopia, myopia'' (nM, M), consisting of nM greater than À0.50 diopters (D; spherical equivalent) and M less than or equal to À0.50 D. A second classification was ''hyperopia, emmetropia, low myopia, and moderate/high myopia'' (H, E, LM, MM) with H greater than or equal to þ1.00 D, E, À0.49 to þ0.99 D, LM, À2.99 to À0.50 D, and MM less than or equal to À3.00 D. Subclassifications were made on the basis of development and progression of myopia over the 2 years. Changes in central refraction over time were determined for different groups, and relative peripheral refraction over time was compared between different subgroups. RESULTS.Simple linear regression of central refraction as a function of relative peripheral refraction did not predict myopia progression as relative peripheral refraction became more hyperopic: relative peripheral hyperopia and relative peripheral myopia predicted significant myopia progression for 0% and 35% of group/visual field angle combinations, respectively. Subgroups who developed myopia did not have more initial relative peripheral hyperopia than subgroups who did not develop myopia.CONCLUSIONS. Relative peripheral hyperopia does not predict development nor progression of myopia in children. This calls into question the efficacy of treatments that aim to slow progression of myopia in children by ''treating'' relative peripheral hyperopia.

Atropine could significantly slow myopia progression in children, with greater effects in Asian than in white children. Randomized controlled trials and cohort studies provided comparable effects.

Within the normal range of variation encountered in these Chinese children, a wide range of activities were largely unrelated to myopia progression at this age. However, there was suggestive evidence that greater time outdoors was associated with slower axial elongation in nonmyopic teenagers, but not in existing myopes.

This study establishes normative peripapillary RNFL values of 12-year-old Chinese children as measured by iVue-100 SD-OCT. The RNFL thickness decreased significantly with increasing axial length and higher myopia.

The 14-year-old group had larger parameter dimensions than the 7-year-old group except for corneal radius of curvature (unchanged) and lens thickness and corneal diameter (both smaller). Boys had large parameter dimensions than girls except for lens thickness (smaller). Axial length, corneal radius of curvature, and lens thickness were the most important determinants of refraction.