Ocular Determinants of Refractive Error and Its Age- and Sex-Related Variations in the Chinese American Eye Study

Suitability of multifunction devices Myah and Myopia Master for monitoring myopia progression in children and adults

PURPOSE

To assess the feasibility of using multifunction instruments to measure axial length for monitoring myopia progression in children and adults.

METHODS

Axial length was measured in 60 children (aged 6-18 years) and 60 adults (aged 19-50 years) with multifunction instruments (Myah and Myopia Master) and stand-alone biometers (Lenstar LS900 and IOLMaster 700). Repeatability (measurements by the same examiner) and reproducibility (measurements by different examiners) were computed as the within-subject standard deviation (Sw) and 95% limits of agreement (LoA). Inter-instrument agreement was computed as intraclass correlation coefficients. The threshold for detecting myopic progression was taken as 0.1 mm. Measures were repeated only in children following the administration of 1% tropicamide to determine the impact of cycloplegia on axial length.

RESULTS

Overall, the IOLMaster 700 had the best repeatability in children (0.014 mm) and adults (0.009 mm). Repeatability Sw values for all devices ranged from 0.005 to 0.021 mm (children) and 0.003 to 0.016 mm (adults). In children, reproducibility fell within 0.1 mm 95% of the time for the Myah, Myopia Master and IOLMaster 700. Agreement among all devices was classified as excellent (ICC 0.999; 95% CI 0.998-0.999), but the 95% LoA among the Myah, Myopia Master and Lenstar LS900 was ≥0.1 mm. Cycloplegia had no statistically significant effect on axial length (all p > 0.13).

CONCLUSIONS

The Myah and Myopia Master multifunction instruments demonstrated good repeatability and reproducibility, and their accuracy was comparable to stand-alone biometers. Axial length measurements using different instruments can be considered interchangeable but should be compared with some caution. Accurate axial length measurements can be obtained without cycloplegia. The multifunction instruments Myah and Myopia Master are as well suited for monitoring myopia progression in children as the stand-alone biometers IOLMaster 700 and Lenstar LS900.

Prescription eyeglasses as a forensic physical evidence: Prediction of age based on refractive error measures using machine learning algorithm

Refractive errors (RE) are commonly reported visual impairment problems worldwide. Previous clinical studies demonstrated age-related changes in human eyes. We hypothesized that the binocular RE metrics including sphere and cylinder power, axis orientation, and interpupillary distance (IPD) can be used for forensic age estimation of an unknown individual. RE data of both eyes were collected from the clinical optometric exams and prescription glasses of 2027 Egyptian individuals aged between 2 to 93 years. The differences between age groups as well as sides, and sexual dimorphism were explored. Two modeling methods were compared: multiple and stepwise linear regression (LR) versus machine learning Regression Forest (RFM). Data were apportioned into training and test datasets with a ratio of 80/20. The results showed significant differences among the age groups in each eye for all variables. Stepwise LR improved the results over models based on the one-sided lens due to selection of IPD in addition to the left and right axis, and left sphere as independent variables. For the RFM, the left axis and IPD were the most important features. RFM outperformed LR in terms of accuracy and root mean squared error (RMSE). The estimated age within ±10 years showed 81.4% accuracy rate and RMSE = 8.9 years versus 38.5% accuracy rate and RMSE = 17.99 years using RFM and stepwise LR, respectively, in the test set. The current study upholds the significance of the age-related changes of refractive error in formulating alternative forensic age estimation models when standard methods are unavailable.

Associations between corneal curvature and other anterior segment biometrics in young myopic adults

To investigate the associations between corneal curvature (CC) and other anterior segment biometrics in young myopic adults. In this retrospective multi-center study, 7893 young myopic adults were included. CC and other anterior segment biometrics were measured by Scheimpflug imaging (Pentacam). CC was defined as SimK at central 3 mm area, and other anterior segment biometrics included white-to-white corneal diameter (WTW), central corneal thickness (CCT), corneal volume (CV) at 3 mm, 5 mm, and 7 mm area, anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), anterior corneal eccentricity (ACE) and asphericity (ACAP), posterior corneal eccentricity (PCE) and asphericity (PCAP), anterior chamber depth (ACD), and anterior chamber volume (ACV). Univariate regression analyses were used to assess the associations between CC and other anterior segment biometrics, and multivariate regression analyses were further performed to adjusted for age, gender and spherical equivalent. CC was higher in patients of female gender and higher myopia (all P < 0.05). Eyes in higher CC quartiles had lower WTW, thinner CCT, lower CV at 3 mm and 5 mm, lower ACD, and lower ACV (all P < 0.001), but had larger ACA, larger PCA, less PCE and less PCAP (all P < 0.001), compared to eyes in lower CC quartiles. The trends of CV at 7 mm, ACE and ACAP were inconsistent in different CC quartiles. After adjusting for age, gender and spherical equivalent with multivariate linear regression, CC was positively correlated to CV at 7 mm (βs = 0.069), ACA (βs = 0.194), PCA (βs = 0.187), ACE (βs = 0.072), PCAP (βs = 0.087), and ACD (βs = 0.027) (all P < 0.05), but was negatively correlated to WTW (βs = - 0.432), CCT (βs = - 0.087), CV-3 mm (βs = - 0.066), ACAP (βs = - 0.043), PCE (βs = - 0.062), and ACV (βs = - 0.188) (all P < 0.05). CC was associated with most of the other anterior segment biometrics in young myopic adults. These associations are important for better understanding of the interactions between different anterior segment structures in young myopic patients, and are also useful for the exploration of the pathogenesis of myopia.

Home confinement's impact on myopia control by using orthokeratology in school-aged children

BACKGROUND

Home confinement during the epidemic has a significant impact on the lifestyle and behavior of school-aged children, who have exhibited an increase in the prevalence and development of myopia. Our research will look at if home confinement will affect school-aged children on myopia control with orthokeratology.

METHOD

Data on axial length was gathered from school-aged children who had received OK lenses treatment. The entire data was separated into subgroups based on gender, age, and initial refraction, and the AL changes for each period were calculated using the formula defined in our study. Finally, the acquired data will be examined using various statistical approaches, and the ideas of slow, moderate, and rapid myopia progression will be applied to our study.

RESULT

A total of 258 study subjects met the requirements to be included in the study. We discovered that the percentage of rapid myopia growth increased during the epidemic. In addition, the AL changes before and during the epidemic were found to be statistically significant in 171 subjects in the overall data. (P = 0.041) In the high age group, the AL changes before and during the epidemic、(P = 0.033) before and after the epidemic (P = 0.023) were found to be statistically significant. The AL changes before and during the epidemic (P = 0.035) were shown to be statistically significant in the moderate myopia group. Finally, we did not find statistically significant results for other groups.

CONCLUSION

We cannot conclude that home confinement did have a negative impact on myopia control with orthokeratology in school-aged children. But we found there was an increase in the percentage of patients with OK treatment that had fast myopia progression during the confinement. We also observed that older children with higher initial refraction were more likely to be affected by home confinement.

Refractive Error and Anterior Chamber Depth as Risk Factors in Primary Angle Closure Disease: The Chinese American Eye Study

PRCIS

The risk of primary angle closure disease (PACD) rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Refractive error (RE) is useful for angle closure risk stratification in the absence of biometric data.

PURPOSE

To assess the role of RE and anterior chamber depth (ACD) as risk factors in PACD.

METHODS

Chinese American Eye Study participants received complete eye examinations including refraction, gonioscopy, amplitude-scan biometry, and anterior segment ocular coherence tomography imaging. PACD included primary angle closure suspect (≥3 quadrants of angle closure on gonioscopy) and primary angle closure/primary angle closure glaucoma (peripheral anterior synechiae or intraocular pressure >21 mm Hg). Logistic regression models were developed to assess associations between PACD and RE and/or ACD adjusted for sex and age. Locally weighted scatterplot smoothing curves were plotted to assess continuous relationships between variables.

RESULTS

Three thousand nine hundred seventy eyes (3403 open angle and 567 PACD) were included. The risk of PACD increased with greater hyperopia [odds ratio (OR) = 1.41 per diopter (D); P < 0.001] and shallower ACD (OR = 1.75 per 0.1 mm; P < 0.001). Hyperopia (≥ + 0.5 D; OR = 5.03) and emmetropia (-0.5 D to +0.5 D; OR = 2.78) conferred a significantly higher risk of PACD compared with myopia (≤0.5 D). ACD (standardized regression coefficient = -0.54) was a 2.5-fold stronger predictor of PACD risk compared with RE (standardized regression coefficient = 0.22) when both variables were included in one multivariable model. The sensitivity and specificity of a 2.6 mm ACD cutoff for PACD were 77.5% and 83.2% and of a +2.0 D RE cutoff were 22.3% and 89.1%.

CONCLUSION

The risk of PACD rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Although RE is a weaker predictor of PACD than ACD, it remains a useful metric to identify patients who would benefit from gonioscopy in the absence of biometric data.

Global metrics on ocular biometry: representative averages and standard deviations across ten countries from four continents

BACKGROUND/OBJECTIVES

We provide global averages and standard deviations for ocular biometry-axial length (AL), corneal radius of curvature (CR), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), and central corneal thickness (CT). We hope a better understanding of normal and abnormal values will help clinicians gain further insight into their surgical outcomes, especially for off-target eyes.

SUBJECTS/METHODS

We searched the MEDLINE database using keywords "axial length, corneal power, anterior chamber depth, lens thickness, white to white, and corneal thickness." We included studies that reported averages and standard deviations on eye biometry for at least 1300 eyes. Global weighted averages and standard deviations were calculated using the Cochrane method.

RESULTS

Fourteen studies were included, originating from Asia (Japan, Singapore, Myanmar, Iran, South Korea, China), Europe (Germany, United Kingdom, Portugal), Australia, and North America (United States). Global ocular biometry metrics were: AL-23.49 mm ± 1.35 mm, CR-7.69 mm ± 0.28 mm, ACD-3.10 mm ± 0.47 mm, WTW-11.80 mm ± 0.42 mm, LT-4.37 mm ± 0.43 mm, and CT-544 μm ± 38 μm. Total eyes per value ranged from 19,538 to 90,814.

CONCLUSIONS

We report global ocular biometry averages and standard deviations. No eyes were from studies in Africa or South America, highlighting the need to publish eye biometry data from these continents. We hope that promoting a deeper understanding of biometry values will help clinicians gain insight into surgical outcomes and drive innovations in lens calculations.

Association between Refractive Errors and Ocular Biometry in an Elderly Population

SIGNIFICANCE

The anterior chamber depth in hyperopic eyes is significantly deeper than that in myopic eyes, and this finding is independent of the axial length.

PURPOSE

This study aimed to determine the relationship between and refractive errors and ocular biometric components in a geriatric population 60 years and older.

METHODS

The present population-based cross-sectional study was performed using a multistage random cluster sampling method in Tehran, Iran. After selecting the samples, visual acuity measurement, autorefraction, subjective refraction, and slit-lamp examination were performed for all participants. Ocular biometric indices were measured with Pentacam AXL (Oculus, Wetzlar, Germany).

RESULTS

The correlation coefficients of spherical equivalent with axial length, corneal radius of curvature, axial length/corneal radius of curvature ratio, and anterior chamber depth were -0.40, 0.14, -0.63, and -0.18, respectively, after controlling the effects of age, sex, and nuclear cataract. The axial length (24.84 vs. 21.21 mm), the anterior chamber depth (2.74 vs. 2.34 mm), the ratio of the axial length to the corneal radius of curvature (3.35 vs. 2.71), and the anterior chamber volume (138.59 and 105.54 mm 3 ) were the highest and lowest in myopic and hyperopic individuals, respectively (all P < .001). In the first model, axial length and nuclear cataract were significantly inversely related to the spherical equivalent. However, corneal radius of curvature, anterior chamber depth, central corneal thickness, and corneal diameter had a significant direct relationship with the spherical equivalent. In the second model, the axial length/corneal radius of curvature ratio and cataract showed an inverse relationship with the spherical equivalent, whereas anterior chamber depth and corneal diameter had a direct relationship with the spherical equivalent.

CONCLUSIONS

Among the biometric components, the axial length/corneal radius of curvature ratio has the strongest relationship with refractive errors. The anterior chamber depth is lower in myopes compared with hyperopes after controlling the effect of axial length.

Sex Differences in Rate of Axial Elongation and Ocular Biometrics in Elementary School Students

Purpose

To determine the relationship between the ocular biometrics and axial length (AL) elongation and its rate in elementary school children.

Methods

This is a prospective observational study of 102 right eyes of third-grade elementary school students who were 8 to 9 years old. All participants underwent measurements of the AL, anterior chamber depth (ACD), and lens thickness (LT) annually for 3 years. The AL elongation during the first half and second half was calculated by subtracting the AL of the 1st year from that at the 2nd year, and AL of the 3rd year minus 2nd year. The total AL elongation (TALE) was obtained by summing up the first and second half AL elongations. The growth rate change (GRC) was obtained by subtracting the first half AL elongation from second half AL elongation. Spearman correlations were used to determine the correlation between the 1st year ocular biometrics and the TALE and GRC.

Results

The mean TALE was 0.54 ± 0.26 mm in boys and 0.46 ± 0.31 mm in girls. The mean GRC was 0.00 ± 0.16 mm in boys and −0.04 ± 0.14 mm in girls. In boys and girls, the TALE was significantly larger in the eyes with myopic ocular biometrics such as a deeper ACD, thinner LT, and longer AL during the 1st year (|r|=0.41 to 0.46, P < 0.05). The GRC was significantly accelerated in the eyes of only the girls with hyperopic ocular biometrics such as a shallower ACD, thicker LT, and shorter AL during the 1st year (|r|=0.31 to 0.41, P<0.05).

Conclusion

In boys and girls, the TALE tends to be larger in eyes with myopic biometrics at the 1st year examination. The GRC tended to accelerate in the eyes with hyperopic ocular biometry during the 1st year only in girls.

Design, methodology, and baseline of whole city-million scale children and adolescents myopia survey (CAMS) in Wenzhou, China

Background

Myopia is the most common visual impairment in children and adolescents worldwide. This study described an economical and effective population-based screening pipeline and performed the project of a million scale children and adolescents myopia survey (CAMS), which will shed light on the further study of myopia from the level of epidemiology and precision medicine.

Methods

We developed a novel population-based screening pattern, an intelligent screening process and internet-based information transmission and analysis system to carry out the survey consisting of school children in Wenzhou, China. The examination items include unaided distance visual acuity, presenting distance visual acuity, and non-cycloplegic autorefraction. Myopia and high myopia were defined as spherical equivalent (SE) ≤ − 1.00 diopters (D) and SE ≤ − 6.00 D, respectively. Next, the reports of the vision checking were automatically sent to parents and the related departments. The CAMS project will be done two to four times annually with the support of the government. An online eyesight status information management system (OESIMS) was developed to construct comprehensive and efficient electronic vision health records (EVHRs) for myopia information inquiry, risk pre-warning, and further study.

Results

The CAMS completed the first-round of screening within 30 days for 99.41% of Wenzhou students from districts and counties, in June 2019. A total of 1,060,925 participants were eligible for CAMS and 1,054,251 (99.37% participation rate) were selected through data quality control, which comprised 1305 schools, and 580,609, 251,050 and 170,967 elementary, middle, and high school students. The mean age of participants was 12.21 ± 3.32 years (6–20 years), the female-to-male ratio was 0.82. The prevalence of myopia in elementary, middle, and high school students was 38.16%, 77.52%, and 84.00%, respectively, and the high myopia incidence was 0.95%, 6.90%, and 12.98%.

Conclusions

The CAMS standardized myopia screening model involves automating large-scale information collection, data transmission, data analysis and early warning, thereby supporting myopia prevention and control. The entire survey reduced 90% of staff, cost, and time consumption compared with previous surveys. This will provide new insights for decision support for public health intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00255-1.

Risk factors for rapid axial length elongation with low concentration atropine for myopia control

Three hundred and twenty-eight myopic children, randomized to use either 0.01% (N = 166) or 0.02% (N = 162) atropine were enrolled in this study. Gender, age, body mass index(BMI), parental myopia status, atropine concentration used, pupil diameter, amplitude of accommodation, spherical equivalent refractive error (SER), anterior chamber depth (ACD) and axial length (AL) were collected at baseline and 1 year after using atropine. Rapid AL elongation was defined as > 0.36 mm growth per year. Univariate analyses showed that children with rapid AL elongation tend to be younger, have a smaller BMI, use of 0.01% atropine, narrow ACD, lower SER, shorter AL, smaller change in pupil diameter between 1 year and baseline (all P < 0.05). Multivariate logistic regression analyses confirmed that rapid AL elongation was associated with children that were younger at baseline (P < 0.0001), use of 0.01% atropine (P = 0.04), a shorter baseline AL (P = 0.03) and a smaller change in pupil diameter between 1 year and baseline (P = 0.04). Younger children with shorter AL at baseline, less change in their pupil diameter with atropine treatment and using the lower of the two atropine concentrations may undergo rapid AL elongation over a 12 months myopia control treatment period.

Axial length and its relationship to refractive error in Chinese university students

PURPOSE

To investigate the relationship between axial length (AL) and refractive error (RE).

METHODS

Participants comprised Chinese university students. In total, 894 eyes with low hyperopia to emmetropia (-0.50D ≤ spherical equivalent (SE) ≤ +2.00D), and 1007 eyes with moderate to high myopia (-11.00D ≤ SE ≤ -4.00D) were analyzed. Cycloplegic RE and AL were measured with an autorefractor and IOL Master respectively. The association between AL and RE was evaluated by linear regression. Furthermore, differences in the mean AL, as well as the correlation between AL and ocular refraction, were evaluated according to SE, sex, and age.

RESULTS

In both the moderate to high myopia and low hyperopia to emmetropia groups, mean AL was significantly longer in men (26.48 mm, confidence interval (CI) 26.41-26.56 mm; 23.82 mm, CI: 23.76-23.88 mm, respectively) than in women (25.78 mm, CI: 25.71-25.86 mm; 23.25 mm, CI: 23.17-23.33 mm, respectively). For both men and women, mean AL significantly differed among four SE groups (+0.50D < SE ≤ +2.00D, -0.50D ≤ SE ≤ +0.50D, -4.00D ≤ SE ≤ -6.00D, SE < -6.00D, P < 0.001). The correlation coefficient between AL and ocular refraction was -0.318 and -0.277 in male and female participants, respectively, with low hyperopia to emmetropia (-0.50D ≤ SE ≤ +2.00D), and -0.545 and -0.437 in male and female participants, respectively, with moderate to high myopia (-11.00D ≤ SE ≤ -4.00D). There were no age-related effects on SE (P = 0.714) or AL (P = 0.952).

CONCLUSIONS

Ocular refraction is negatively correlated with AL in Chinese university students. The correlation coefficient is greater in those with moderate to high myopia than in those with low hyperopia to emmetropia. Furthermore, the AL is longer in men than in women.

Ocular Biometric Determinants of Anterior Chamber Angle Width in Chinese Americans: The Chinese American Eye Study

PURPOSE

We sought to investigate anatomic mechanisms of angle narrowing by assessing ocular biometric determinants of anterior chamber angle width.

DESIGN

Population-based cross-sectional study.

METHODS

Subjects ≥50 years of age from the Chinese American Eye Study underwent a comprehensive ocular examination, including anterior segment optical coherence tomography imaging and ultrasound A-scan. Independent variables, including anterior chamber depth (ACD), lens vault (LV), iris curvature (IC), anterior chamber width, lens thickness, vitreous cavity depth, and axial length, and dependent variables, including angle opening distance, were measured in 1 randomly selected eye per subject. Univariable and multivariable regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squares (SPCC²) were used to assess relative and unique contributions by independent variables to angle width.

RESULTS

Two thousand two hundred twenty-five subjects (1433 women and 834 men) were included in the analysis. All biometric parameters except lens thickness differed between men and women (age-adjusted P < .001). In model 1A (R² = 0.66), which included ACD, lens thickness, and vitreous cavity depth, ACD (SRC = 0.64, SPCC² = 0.19) and IC (SRC = -0.26, SPCC² = 0.041) were the strongest determinants of angle opening distance. In model 1B (R² = 0.58), which included LV and axial length, LV (SRC = -0.46, SPCC² = 0.1) and IC (SRC = -0.3, SPCC² = 0.047) were the strongest determinants of angle opening distance. Determinants of angle width were similar in separate multivariable models for men and women.

CONCLUSIONS

ACD, LV, and IC are the strongest determinants of angle width in Chinese Americans. Sex-related differences in angle width are explained by differences among biometric measurements. These results provide insights into anatomic mechanisms of angle narrowing and have important implications for quantitative assessments of angle closure eyes.

Visual impairment in highly myopic eyes: The ZOC-BHVI High Myopia Cohort Study

IMPORTANCE

Understanding visual impairment (VI) under different definitions and potential risk factors in high myopic is important for future myopia control.

BACKGROUND

Limited studies exists investigating the VI among high myopic and with varying VI definitions.

DESIGN

Registry cohort study.

PARTICIPANTS

Eight hundred and eighty-four participants were from ZOC-BHVI study.

METHODS

Subjects aged 7 to 70 years with high myopia were enrolled. Uncorrected visual acuity and best-corrected visual acuity (UCVA and BCVA), cycloplegic refraction, axial length (AL), corneal curvatures, anterior chamber depth and lens thickness were measured. Axial length/corneal radius of curvature ratio (AL/CR ratio) was calculated. Fundus lesions were graded into five categories. VI and blindness were defined based on the better-seeing eye according to the World Health Organization (WHO) criteria and US criteria. Multiple logistic regression analysis was used to assess risk factors for VI.

MAIN OUTCOME MEASURES

Rates of VI and blindness.

RESULTS

A total of 884 participants were included, with mean (SD) age 18.5 (12.4) years and 46.4% male. Rate of UCVI/blindness were 72.6%/27.3% and 17.9%/82.1% based on WHO and US criteria. With respect to BCVA, 4.1%/5.9% of participants had BCVI using two definitions, whereas the rate for blindness was 0.2% and 0.6%. After adjusting confounders, multiple logistic regression showed that more severe fundus lesions, greater AL/CR ratio were at a higher risk of being VI, both in two definitions (P < .005).

CONCLUSIONS AND RELEVANCE

The rate of VI and blindness in highly myopic patients varies significantly using different definition. Severe fundus lesions and greater AL/CR ratios were associated with a higher risk of VI.

Correlations between ocular biometrics and refractive error: A systematic review and meta-analysis

The understanding of correlations between different biometric parameters is essential for personalized eye care in the field of cataract and refractive surgery. This systematic review offers a clear overview of the previous literature assessing these correlations including a meta-analysis. The review is focused on the following five correlations: (1) axial length and refractive error; (2) anterior chamber depth and refractive error; (3) axial length and anterior chamber depth; (4) corneal power and refractive error; (5) corneal power and axial length. An expected strong correlation between axial length and refractive error was found. Correlations including corneal power were weak and might be clinically insignificant.

IMI - Clinical Myopia Control Trials and Instrumentation Report

The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

Effect of cycloplegia on the measurement of refractive error in Chinese children

Background

To compare the results of cycloplegic and non‐cycloplegic refractive error measurement in Chinese children, and to assess the relationship between age and the difference in refractive error measured with and without cycloplegia.

Methods

This was a prospective study that recruited 224 healthy Chinese children at an ophthalmology clinic from November 2016 to February 2017. Refraction before and after cycloplegia were measured using an auto‐refractor. Then spherical equivalent M, J₀, and J₄₅ were calculated. The enrolled children were allocated into three groups according to M: myopia, emmetropia, and hyperopia. The distribution of the refraction was further analysed by stratifying by age: four to six years, seven to 11 years, and 12 to 16 years.

Results

Mean non‐cycloplegic M, J₀, and J₄₅ were −1.68 ± 2.00 D, 0.05 ± 0.40 D, and 0.01 ± 0.35 D, while mean cycloplegic M, J₀, and J₄₅ were −1.16 ± 2.17 D, 0.02 ± 0.40 D, and −0.01 ± 0.35 D. Significant differences were found between cycloplegic and non‐cycloplegic M (p = 0.009), whereas there were no significant differences between cycloplegic and non‐cycloplegic J₀ and J₄₅ (p = 0.486 and p = 0.594, respectively). The differences between cycloplegic and non‐cycloplegic M were statistically significant in the four to six years group (p = 0.002) and seven to 11 years group (p = 0.023), whereas there was no significant difference between cycloplegic and non‐cycloplegic M in the 12 to 16 years group (p = 0.151). The proportion of myopia decreased from 78.1 per cent before cycloplegia to 71.4 per cent after cycloplegia, while the proportion of hyperopia increased from 12.1 per cent before cycloplegia to 21.4 per cent after cycloplegia.

Conclusion

Non‐cycloplegic auto‐refraction is found to be inaccurate and not suitable for studies of refractive error in Chinese children.