Pre- and Postcycloplegic Refractions in Children and Adolescents

Retinoscopes: Past and present

BACKGROUND

Retinoscopy is arguably the most important method in the eye clinic for diagnosing and managing refractive errors. Advantages of retinoscopy include its non-invasive nature, ability to assess patients of all ages, and usefulness in patients with limited cooperation or communication skills.

AIM

To discuss the history of retinoscopes and examine current literature on the subject.

METHODS

A search was conducted on the PubMed and with the reference citation analysis (https://www.referencecitationanalysis.com) database using the term “Retinoscopy,” with a range restricted to the last 10 years (2013-2023). The search string algorithm was: "Retinoscopy" (MeSH Terms) OR "Retinoscopy" (All Fields) OR "Retinoscopes" (All Fields) AND [(All Fields) AND 2013: 2023 (pdat)].

RESULTS

This systematic review included a total of 286 records. Publications reviewed iterations of the retinoscope into autorefractors, infrared photo retinoscope, television retinoscopy, and the Wifi enabled digital retinoscope.

CONCLUSION

The retinoscope has evolved significantly since its discovery, with a significant improvement in its diagnostic capabilities. While it has advantages such as non-invasiveness and broad applicability, limitations exist, and the need for skilled interpretation remains. With ongoing research, including the integration of artificial intelligence, retinoscopy is expected to continue advancing and playing a vital role in eye care.

A clearer vision: unveiling the importance of cycloplegic refraction and the pseudomyopia prevalence in Chinese preschoolers

BACKGROUND

This study aimed to investigate the difference between cycloplegic and noncycloplegic refraction and evaluate the pseudomyopia prevalence in Chinese preschool children during the outbreak of COVID-19.

METHODS

A cross-sectional study was conducted in the Tongzhou District of Beijing, China. Refractive error was measured under both noncycloplegic and cycloplegic conditions with autorefraction. The difference between noncycloplegic and cycloplegic spherical equivalent refraction (SER) and pseudomyopia prevalence were analyzed. Pseudomyopia was defined as SER ≤-0.50D in precycloplegic assessments and >-0.50D in post-cycloplegic assessments.

RESULTS

Out of the 1487 participants who were enrolled in the study, 1471 individuals (98.92%) between the ages of 3-6 years completed all required procedures. A statistically significant difference in refraction was observed between noncycloplegic and cycloplegic measurements, the median of difference in spherical equivalent refraction (SER) of 0.88D (dioptre)(0.50,1.38). There was a high intraclass correlation (ICC) between these two methods for cylinders (ICC = 0.864; 95% CI, 0.850-0.877). The median DSE for myopia, emmetropia and hyperopia were 0.25D (0.00, 0.38),0.25D (0.06, 0.50) and 1.00D (0.62, 1.38), an hypermetropes showed considerably greater differences than myopes and emmetropes (Kruskal-Wallis test, H = 231.023, P = 0.000). Additionally, girls displayed a greater DSE than boys. Furthermore, when comparing against-the-rule (ATR) and oblique astigmatism, it was found that with-the-rule (WTR) astigmatism had the largest DSE. The study found varying prevalence rates of myopia, emmetropia, and hyperopia with and without cycloplegia, which were 1.90% vs. 10.06%, 11.49% vs. 50.31%, and 86.61% vs. 39.63%, respectively. Additionally, the overall prevalence of pseudomyopia was determined to be 8.29%. Participants with pseudomyopia had a significantly higher mean difference in SER (DSE) compared to non-pseudomyopic participants.

CONCLUSIONS

Cycloplegic refraction is more sensitive than a noncycloplegic one for measuring refractive error in preschool children. Pseudomyopia is prevalent in preschool children during the COVID-19 outbreak period. Our study indicates the possibility that cycloplegic refraction should be performed in preschool children routinely.

The impact of accommodation function on the difference between noncycloplegic and cycloplegic refraction in adult myopes

PURPOSE

To investigate the impact of accommodation function on the difference between cycloplegic and noncycloplegic subjective and automatic refraction in adult myopes.

METHODS

Myopic patients between 18 and 50 years old evaluated at Peking University Third Hospital who underwent cycloplegic and noncycloplegic automatic and subjective refraction were enrolled. Accommodation function, including negative and positive relative accommodation (PRA/NRA) and accommodation response (binocular cross cylinder, BCC) was examined.

RESULTS

Of the 3268 individuals enrolled, the mean age was 27.3 ± 6.9 years, and 34.8% of participants were male. The noncycloplegic spherical equivalent (SE) was 0.23 ± 0.29 D and 0.64 ± 0.61 D more myopic than cycloplegic subjective and automatic refraction. Adjusting for associated factors, participants with at least 0.50 D of more myopia SE refraction by noncycloplegic subjective refraction were more likely to be older (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.013-1.045) and with insufficient (OR, 1.514; 95% CI, 1.093-2.096) and excessive (OR, 2.196; 95% CI, 1.538-3.137) NRA value. The automatic refraction SE difference of at least 1.00 D more myopia was more likely to be found in individuals with older age (OR, 1.036; 95% CI, 1.022-1.050) and accommodative lead (OR, 1.255; 95% CI, 1.004-1.568).

CONCLUSION

A quarter of adult myopes had at least 0.50 and 1.00 D of subjective and automatic SE difference with cycloplegia. The accommodation function significantly affects the difference between cycloplegic and noncycloplegic refraction. Investigating the differences in refraction measurement guarantees the proper use of cycloplegia in adults for myopia correction.

Changes in ocular biometrics following cycloplegic refraction in strabismic and amblyopic children

This study was aimed to analyze ocular biometric changes following cycloplegia in pediatric patients with strabismus and amblyopia. Cycloplegia is routinely used to measure refractive error accurately by paralyzing accommodation. However, effects on axial length (AL), anterior chamber depth (ACD), keratometry (Km), and white-to-white distance (WTW) are not well studied in this population. This retrospective study examined 797 patients (1566 eyes) undergoing cycloplegic refraction at a Samsung Kangbuk hospital pediatric ophthalmology clinic from 2010 to 2023. Ocular biometry was measured before and after instilling 1% cyclopentolate and 0.5% phenylephrine/0.5% tropicamide. Patients were categorized by strabismus diagnosis, age, refractive error and amblyopia status. Differences in AL, ACD, Km, WTW, and refractive error pre- and post-cycloplegia were analyzed using paired t tests. ACD (3.44 ± 0.33 vs 3.58 ± 0.29 mm, P < .05) and WTW (12.09 ± 0.42 vs 12.30 ± 0.60 mm, P < .05) increased significantly after cycloplegia in all groups except other strabismus subgroup (Cs) in both parameters and youngest subgroup (G1) in ACD. Refractive error demonstrated a hyperopic shift from -0.48 ± 3.00 D to -0.06 ± 3.32 D (P < .05) in overall and a myopic shift from -6.97 ± 4.27 to -8.10 ± 2.26 in high myopia (HM). Also, AL and Km did not change significantly. In conclusion, cycloplegia impacts ocular biometrics in children with strabismus and amblyopia, significantly increasing ACD and WTW. Refractive error shifts hyperopically in esotropia subgroup (ET) and myopically in high myopia subgroup (HM), eldest subgroup (G3) relating more to anterior segment changes than AL/Km. Understanding cycloplegic effects on biometry is important for optimizing refractive correction in these patients.

Method comparison and overview of refractive measurements in children: implications for myopia management

OBJECTIVE

This study investigated the agreement between objective wavefront-based refraction and subjective refraction in myopic children. It also assessed the impact of cyclopentolate and refraction levels on the agreement.

METHODS

A total of 84 eyes of myopic children aged 6-13 years were included in the analysis. Non-cycloplegic and cycloplegic objective wavefront-based refraction were determined and cycloplegic subjective refraction was performed for each participant. The data were converted into spherical equivalent, J0 and J45, and Bland-Altman plots were used to analyse the agreement between methods.

RESULTS

Linear functions were used to determine the dependency between the central myopic refractive error and the difference between the method of refraction (=bias). The influence of central myopia was not clinically relevant when analysing the agreement between wavefront results with and without cyclopentolate (comparison 1). The bias for wavefront-based minus subjective spherical equivalent refraction (comparison 2) was ≤-0.50 D (95% limits of agreement -0.010 D to -1.00 D) for myopia of -4.55 D and higher when cycloplegia was used (p<0.05). When no cyclopentolate was used for the wavefront-based refraction (comparison 3), the bias of -0.50 D (95% limits of agreement -0.020 D to -0.97 D) was already reached at a myopic error of -2.97 D. Both astigmatic components showed no clinically relevant bias.

CONCLUSION

The spherical equivalent, measured without cycloplegic agents, led to more myopic measurements when wavefront-based refraction was used. The observed bias increased with the amount of myopic refractive error for comparisons 2 and 3, which needs to be considered when interpreting wavefront-refraction data.

TRIAL REGISTRATION NUMBER

NCT05288335.

The association between iris color and refractive errors in children

This study aimed to evaluate the association between iris color and refractive errors in children aged 6-12 years. This cross-sectional study was based on data obtained from the first phase of the Shahroud Schoolchildren Eye Cohort Study. The target population was 6 to12 year-old students living in urban and rural areas. Iris colors were classified by comparing eye colors with close-up images of iris colors. Myopia was defined as a spherical equivalent (SE) ≤ - 0.5 diopter and hyperopia was defined as SE ≥ 2 diopter in cycloplegic refraction. The association of iris color with hyperopia and myopia was investigated by fitting two separate multiple logistic regression models adjusted for place of residence, age, sex, and times for outdoor activity and near work. Among the 5394 participates with the mean age of 9.7 year, the prevalence of myopia and hyperopia was 4.8% and 4.7% respectively. The number and proportion (in parentheses) of amber, light blue, light brown, dark brown, gray, green and hazel iris colors were 19(0.4%), 26(0.5%), 645(12.0%), 4517(83.7%), 4(0.1%), 59(1.1%), and 124(2.3%) respectively. Compared to dark brown, the odds ratios and 95% confidence intervals (in parentheses) of myopia were 4.8(1.2-18.7), 0.8(0.1-5.8), 1.0(0.7-1.5), 0.4(0.1-2.7) and 0.6(0.2-1.8) for amber, light blue, light brown, green and hazel iris colors in multiple logistic regression model. No significant association was observed between iris colors and hyperopia. This study shows that amber iris is significantly associated with higher odds of myopia. These children should be further monitored and examined. More studies with higher sample size in all iris colors are recommended.

Comparison of cycloplegia with atropine 1% versus cyclopentolate 1

PURPOSE

Cycloplegic refraction is mandatory for children to know the eye's refractive status. In this study, we compared cycloplegia induced by cyclopentolate 1% to that induced by atropine 1% by means of retinoscopy.

METHODS

In this parallel-designed interventional study, we included 67 children aged between 4 and 17 years. After the initial retinoscopy under cyclopentolate 1% (used twice in each eye), we repeated it a week later under atropine ointment 1% (used twice a day for 3 days); both were done by the same trained optometrist masked to the drug. Each eye's refraction was converted to spherical equivalents (SEs), and the values averaged between the two eyes of each child under each drug. We compared SE with paired t-test (JASP 16.4). In addition, we performed correlational analysis, and looked for agreement using the Bland-Altman plot. Significance was set at P < 0.05. Wherever possible, 95% confidence intervals (CIs) are quoted.

RESULTS

The mean SE with atropine was +1.93 ± 2.0 D, compared to +1.75 ± 1.95 D under cyclopentolate. On average, atropine induced greater cycloplegia by a mere 0.18 D (95% CI: 0.07 to 0.29 D, P value 0.002). The two cycloplegic refractions correlated significantly (Pearson's r: 0.975, P < 0.001). The Bland-Altman plot revealed the limits of agreement as 1.06 and -0.71 D.

CONCLUSION

Our study suggests that cyclopentolate works for the most part as well as atropine to attain cycloplegia. Atropine may be considered for children less than 15 years of age with greater than 5.0 D of hyperopia. Cycloplentolate, with its advantages of quick action and short duration, should form the first go-to topical cycloplegic in busy outpatient clinics.

Refractive Error and Axial Length and Their Related Factors in 8-Year-Old Japanese Children: The Yamanashi Adjunct Study of the Japan Environment and Children's Study (JECS)

PURPOSE

To investigate the distribution of visual acuity, refractive error, and axial length in 8-year-old children who participated in an additional survey in Yamanashi Prefecture of the Japan Environmental Children's Study (hereafter referred to as JECS-Y) conducted from 2019 to 2021.

PARTICIPANTS AND METHODS

Eight-year-old children who participated in the JECS-Y study were subjected to noncycloplegic measurements of refractive error and axial length. If the uncorrected visual acuity was less than 20/20, the best corrected visual acuity was evaluated in accordance with the autorefraction data. A questionnaire was administered regarding the parent's history of eyeglass wear or contact lens use.

RESULTS

Among the 400 participating children, the rate of uncorrected visual acuity of 20/20 or better in both eyes was 70.4%. The mean equivalent spherical equivalent error for both eyes was -0.366 ± 1.016 D. The mean axial length was 23.08 ± 0.225 mm in all patients. The males showed significantly longer axial length than the females despite no differences in body height. There was a significant correlation between axial length, spherical refractive, and uncorrected visual acuity. The children of parents with a history of wearing eyeglasses or contact lenses showed a significantly more myopic equivalent refractive error than those without a history.

CONCLUSIONS

This study clarified the current state of refractive error in 8-year-old children and the association of inheritance with refractive error. In addition, the axials were significantly longer in male patients.

Measures and variability with age of low contrast acuity and near stereoacuity in children

CLINICAL RELEVANCE

Low contrast acuity (LCA) and near stereoacuity (NS) testing are integral to the comprehensive assessment of sensory visual function in children. However, routine ophthalmological evaluations seldom take these measures into consideration. Additionally, there is limited literature regarding the normative values of these parameters in children.

BACKGROUND

This study investigated LCA and NS measures and their variability in children with normal visual acuity. The aim was to provide a benchmark for distinguishing normal measures from abnormal ones.

METHODS

A prospective observational study was conducted in primary and secondary schools across North India. The participants numbered 240 children, aged between 3 and 15 years. They were split into 12 smaller groups of 20 participants in each age group. Only participants with normal monocular uncorrected visual acuity, no refractive error, normal birth history, and no systemic ailments, were recruited. All the participants underwent a complete ophthalmic examination and non-cycloplegic retinoscopy. LCA was measured, using the low contrast Lea number chart at three metres. NS was measured using the Randot® stereo test at 40 cm.

RESULTS

The percentages of males and females, were found to be 55%, and 45%, respectively (p = 0.093). The mean NS was found to be 38.7 ± 11.5 arcsecs in the 3-9-year age group, and 26.7 ± 5.6 arcsecs in the 9-15-year age group (p-value <0.001). The mean NS showed an increasing trend up to 9 years of age. The mean LCA was 64.4 ± 20.1 in the age group of 3-8 years, and 76.38 ± 11.39 in the age group of 8-15 years (p-value <0.001). Considerable variability was noted in the LCA in the younger age group (p-value = 0.000).

CONCLUSIONS

LCA and NS mature gradually during childhood. LCA stabilises after the age of 8, while NS stabilises after the age of 9.

Accuracy and intrasession variability of noncycloplegic autorefraction of school-aged children and adolescents

The aims of the study were (1) to compare the accuracy and intrasession variability of noncycloplegic autorefraction (AR) obtained by a photorefractor and conventional and open-field autorefractors and (2) to evaluate the impact of accommodative and binocular vision anomalies on the accuracy of autorefraction. Twenty-nine children and adolescents aged 8-18 years were examined. All instruments gave more myopic results than subjective refraction (SR). Mean differences between the SR and the AR were +0.52/-0.25×96∘ for the photorefractor, +0.63/-0.31×93∘ for the conventional autorefractor, and +0.19/-0.26×94∘ for the open-field instrument. The photorefractor appeared to be the most repeatable. The impact of the examined vision anomalies on the accuracy of autorefraction was not statistically significant.

Refractive Errors and Their Associated Factors in Schoolchildren: A Structural Equation Modeling

PURPOSE

To determine the prevalence of myopia and hyperopia in Shahroud schoolchildren and their risk factors.

METHODS

Optometric examinations including the measurement of uncorrected and corrected visual acuity as well as non-cycloplegic and cycloplegic refraction using retinoscopy were done for students. Generalized Structural Equation Modeling (GSEM) was used to determine direct and indirect effects of independent variables on myopia and hyperopia.

RESULTS

The data of 5581 students with a mean age of 9.24 ± 1.7 years were used in this study. The prevalence of myopia was 5.0% (95%CI: 4.3-5.7) and the prevalence of hyperopia was 4.8% (95%CI: 4.0 - 5.5) in all schoolchildren. According to the GSEM results, the odds of myopia in rural areas were 0.55 compared to urban areas. A one-unit increase in the ocular AL increased the odds of myopia by 4.91 times. The interaction of sex and age on myopia was significant such that in girls, the odds of myopia increased by 20% for every one-year increase in age while no significant change was seen in boys. A one-unit increase in the ocular AL decreased the odds of hyperopia by 0.49 times. Moreover, the interaction of outdoor activity hours and sex on the prevalence of hyperopia was significant such that increased outdoor activity reduced the odds of hyperopia in girls while no significant correlation was found in boys.

CONCLUSION

Myopia and hyperopia had moderate prevalence. Axial Length had the largest direct association on myopia and hyperopia. Age and outdoor activity had weak associations on refractive errors.

Deep learning system to predict the 5-year risk of high myopia using fundus imaging in children

Our study aims to identify children at risk of developing high myopia for timely assessment and intervention, preventing myopia progression and complications in adulthood through the development of a deep learning system (DLS). Using a school-based cohort in Singapore comprising of 998 children (aged 6-12 years old), we train and perform primary validation of the DLS using 7456 baseline fundus images of 1878 eyes; with external validation using an independent test dataset of 821 baseline fundus images of 189 eyes together with clinical data (age, gender, race, parental myopia, and baseline spherical equivalent (SE)). We derive three distinct algorithms - image, clinical and mix (image + clinical) models to predict high myopia development (SE ≤ -6.00 diopter) during teenage years (5 years later, age 11-17). Model performance is evaluated using area under the receiver operating curve (AUC). Our image models (Primary dataset AUC 0.93-0.95; Test dataset 0.91-0.93), clinical models (Primary dataset AUC 0.90-0.97; Test dataset 0.93-0.94) and mixed (image + clinical) models (Primary dataset AUC 0.97; Test dataset 0.97-0.98) achieve clinically acceptable performance. The addition of 1 year SE progression variable has minimal impact on the DLS performance (clinical model AUC 0.98 versus 0.97 in primary dataset, 0.97 versus 0.94 in test dataset; mixed model AUC 0.99 versus 0.97 in primary dataset, 0.95 versus 0.98 in test dataset). Thus, our DLS allows prediction of the development of high myopia by teenage years amongst school-going children. This has potential utility as a clinical-decision support tool to identify "at-risk" children for early intervention.

Refractive prescribing for preschool children by optometrists in England

PURPOSE

Correction of refractive error in children is important for visual and educational development. The aim of this questionnaire-based study was to explore paediatric refractive correction by optometrists in England.

METHODS

An online questionnaire was piloted and distributed to optometrists in England. The questionnaire asked about respondents' characteristics (such as type of practice), management of refractive error in 1- and 3-year-old children and sources of information used as a basis for decisions on prescribing refractive error in children.

RESULTS

Two hundred and ninety-three questionnaires were returned, although only 139 (47%) were fully completed. In an average month, about half of respondents examined no children between 0 and 2 years of age, and about half examined no more than five children aged 3-4 years. A significant proportion indicated they would refer children aged 1 or 3 years with refractive error and no other signs or symptoms into the hospital eye service. Almost a quarter would prescribe in full or in part an isometropic refractive correction of +2.00 D for a 3-year-old (within the normal range) with no other signs or symptoms, suggesting a degree of unnecessary prescribing. Almost all would act in cases of clinically significant refractive error. Respondents made similar use of their colleagues, optometric or postgraduate/continuing education, professional guidance and peer-reviewed research as sources of evidence on which to base decisions about prescribing for paediatric refractive errors. Most reported 'never' or 'rarely' using Cochrane reviews.

CONCLUSIONS

These results suggest optometrists often defer management of paediatric refractive error to the hospital eye service, with implications in terms of underutilisation of community optometric expertise and burden on the National Health Service. In some cases, the results indicate a mismatch between respondents' reported management and existing guidance/guidelines on paediatric prescribing.

Prediction of spherical equivalent difference before and after cycloplegia in school-age children with machine learning algorithms

Purpose

To predict the need for cycloplegic assessment, as well as refractive state under cycloplegia, based on non-cycloplegic ocular parameters in school-age children.

Design

Random cluster sampling.

Methods

The cross-sectional study was conducted from December 2018 to January 2019. Random cluster sampling was used to select 2,467 students aged 6-18 years. All participants were from primary school, middle school and high school. Visual acuity, optical biometry, intraocular pressure, accommodation lag, gaze deviation in primary position, non-cycloplegic and cycloplegic autorefraction were conducted. A binary classification model and a three-way classification model were established to predict the necessity of cycloplegia and the refractive status, respectively. A regression model was also developed to predict the refractive error using machine learning algorithms.

Results

The accuracy of the model recognizing requirement of cycloplegia was 68.5-77.0% and the AUC was 0.762-0.833. The model for prediction of SE had performances of R^2 0.889-0.927, MSE 0.250-0.380, MAE 0.372-0.436 and r 0.943-0.963. As the prediction of refractive error status, the accuracy and F1 score was 80.3-81.7% and 0.757-0.775, respectively. There was no statistical difference between the distribution of refractive status predicted by the machine learning models and the one obtained under cycloplegic conditions in school-age students.

Conclusion

Based on big data acquisition and machine learning techniques, the difference before and after cycloplegia can be effectively predicted in school-age children. This study provides a theoretical basis and supporting evidence for the epidemiological study of myopia and the accurate analysis of vision screening data and optometry services.

Increasing prevalence of myopia and the impact of education in primary-school students in Xi'an, north-western of China

Purpose

The present study was performed to detect the prevalence of myopia among primary-school students in Xi'an, north-western of China.

Methods

The present study was a school-based study with students aged from 6 to 13 years old. All the individuals underwent ophthalmological examination and spherical equivalent (SE) of refractive error were measured with non-cycloplegic refraction. Myopia was defined as a SE of ≤ -0.5 diopters (D), and further divided into three stratified groups based on SE: low myopia (≤ -0.5 to >-3.0 D), moderate myopia (≤ -3.0 to >-6.0 D), and high myopia (≤ -6.0 D). Relative risk factors, including age, sex, grade and ethnicity were investigated using questionnaire.

Results

A total of 4,680 individuals were eligible for this survey and 4,654 (99.4% participation rate) were finally included (51.2% boys). The mean age of participants was 8.756 ± 1.727 years. The whole city-level prevalence of total myopia was 57.1% (95% CI: 55.7-58.6%). Additionally, the prevalence of low, moderate, and high myopia was 45.0% (95% CI: 43.5-46.4%), 11.1% (95% CI: 10.2-12.0%), and 1.0% (95% CI: 0.7-1.3%), respectively. Moreover, grade (education level) instead of age, sex and ethnicity was the most essential risk factor for prevalence of overall myopia (OR = 1.844, 95% CI: 1.605-2.119), and an increase of prevalence by 84.4% per grade was seen. Furthermore, similar associations of grade were significant with low myopia (OR = 1.613, 95% CI: 1.385-1.877) and moderate myopia (OR = 2.186, 95% CI: 1.693-2.823), meanwhile, prevalence of low myopia and moderate myopia demonstrated an increase of prevalence by 61.3 and 118.6% per grade, respectively. None of the factors included in the present study was significant risk factor for high myopia.

Conclusions

The present study investigated a non-negligible high prevalence of myopia among primary-school students in Xi'an, north-western of China, and a gradual increasing in proportion with education level.

Systematic review and meta-analysis on the agreement of non-cycloplegic and cycloplegic refraction in children

OBJECTIVE

To determine the diagnostic agreement of non-cycloplegic and cycloplegic refraction in children.

METHOD

The study methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases were searched for comparative studies exploring refraction performed on children under non-cycloplegic and cycloplegic conditions. There was no restriction on the year of publication; however, only publications in the English language were eligible. Inclusion criteria consisted of children aged ≤12 years, any degree or type of refractive error, either sex and no ocular or binocular co-morbidities. The QUADAS-2 tool was used to evaluate the risk of bias. Meta-analysis was conducted to synthesise data from all included studies. Subgroup and sensitivity analyses were undertaken for those studies with a risk of bias.

RESULTS

Ten studies consisting of 2724 participants were eligible and included in the meta-analysis. The test for overall effect was not significant when comparing non-cycloplegic Plusoptix and cycloplegic autorefractors (Z = 0.34, p = 0.74). The pooled mean difference (MD) was -0.08 D (95% CI -0.54 D, +0.38 D) with a prediction interval of -1.72 D to +1.56 D. At less than 0.25 D, this indicates marginal overestimation of myopia and underestimation of hyperopia under non-cycloplegic conditions. When comparing non-cycloplegic autorefraction with a Retinomax and Canon autorefractor to cycloplegic refraction, a significant difference was found (Z = 9.79, p < 0.001) and (Z = 4.61, p < 0.001), respectively.

DISCUSSION

Non-cycloplegic Plusoptix is the most useful autorefractor for estimating refractive error in young children with low to moderate levels of hyperopia. Results also suggest that cycloplegic refraction must remain the test of choice when measuring refractive error ≤12 years of age. There were insufficient data to explore possible reasons for heterogeneity. Further research is needed to investigate the agreement between non-cycloplegic and cycloplegic refraction in relation to the type and level of refractive error at different ages.

Noncycloplegic Compared with Cycloplegic Refraction in a Chicago School-Aged Population

PURPOSE

To evaluate differences between autorefraction measurements with and without cycloplegia among school-aged individuals and to explore factors associated with significant differences.

DESIGN

Cross-sectional, retrospective study.

PARTICIPANTS

Individuals between 3 and 22 years of age evaluated at the Illinois College of Optometry from September 2016 through June 2019 who underwent same-day noncycloplegic and cycloplegic autorefraction of the right eye.

METHODS

Demographic information including age, sex, and race or ethnicity were collected during the eye examination. Autorefraction was performed before and after cycloplegia. Myopia, defined as at least -0.50 diopter (D) spherical equivalent (SE), hyperopia, defined as at least +0.50 D SE, and astigmatism of at least 1.00 D cylinder were determined using noncycloplegic and cycloplegic autorefractions. Factors associated with at least 1.00 D more myopic SE or at least 0.75 D cylindrical difference by noncycloplegic autorefraction were assessed using logistic regression models.

MAIN OUTCOME MEASURES

Differences between noncycloplegic and cycloplegic autorefraction measurements.

RESULTS

The mean age was 10.8 ± 4.0 years for the 11 119 individuals; 52.4% of participants were female. Noncycloplegic SE measured 0.65 ± 1.04 D more myopic than cycloplegic SE. After adjusting for demographic factors and refractive error, individuals with at least 1.00 D of more myopic SE refraction by noncycloplegic autorefraction (25.9%) were more likely to be younger than 5 years (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.18-1.79) and 5 to younger than 10 years (OR, 1.32; 95% CI, 1.18-1.48) than those 10 to younger than 15 years. This difference of at least 1.00 D of more myopic SE was more likely to be observed in Hispanic people (OR, 1.23; 95% CI, 1.10-1.36) and those with hyperopia (OR range, 4.20-13.31). Individuals with 0.75 D or more of cylindrical difference (5.1%) between refractions were more likely to be younger than 5 years, to be male, and to have mild-moderate-high myopia or moderate-high hyperopia.

CONCLUSIONS

Three quarters of school-aged individuals had < 1 D of myopic SE difference using noncycloplegic compared with cycloplegic autorefraction. Understanding measurement differences obtained for refractive error and associated factors may provide useful information for future studies or programs involving refraction in school-aged children.

Beijing Pinggu Childhood Eye Study: The Baseline Refractive Characteristics in 6- to 12-Year-Old Chinese Primary School Students

Purpose

To report the design and baseline data of a 3-year cohort study in Beijing Pinggu District primary school students in China after COVID-19.

Methods

Noncycloplegic and cycloplegic spherical equivalent refraction (SER) were measured, ocular biometry, including the axial length (AL), anterior chamber depth (ACD) and corneal power (CP), were collected before cycloplegia. Corneal radius (CR), AL-to-CR ratio, and lens power (LP) were calculated.

Results

Among the 4,806 (89.1%) eligible students (51.5% male), the prevalence of emmetropia, myopia, mild hyperopia, and mild-to-high hyperopia was 12.8, 30.8, 53.0, and 3.3% after cycloplegia, respectively. Myopia increased from 2.5% in 6- to 71.6% in 12-year-old students, with 9- and 10-year-olds showing the most prominent increases. The median of cycloplegic SER was 0.50 (IQR = 1.63), and the noncycloplegic SER was −0.38 D (IQR = 1.50), which is more negative than the cycloplegic refraction. The mean AL increased with age, from 22.46 ± 0.70 mm to 24.26 ± 1.07 mm. The ACD increased from 3.38 ± 0.28 mm to 3.70 ± 0.30 mm, and the AL-to-CR ratio increased from 2.91 ± 0.08 to 3.12 ± 0.13 between 6- and 12-year-old students. AL, CR and LP explained the SER variance with R² of 86.4% after adjusting the age and gender.

Conclusions and Relevance

The myopia prevalence since emergence of COVID-19 rapidly increased from 6- to 12-year primary school Chinese children, especially after 7 years of age. The non-cycloplegia SER overestimated the prevalence of myopia, and the cycloplegic SER is a more accurate and reliable method to assess the prevalence of refractive status.

Photoscreener results with and without cycloplegia and their reliability according to biometric parameters

PURPOSE

Our goal in this study is to compare the results of a photoscreener (Plusoptix A12C) with and without cycloplegia and to investigate its reliability as a function of biometric parameters.

METHODS

In total, 250 eyes of 125 children with a mean age of 6.77±1.59years were included in the study. The results of cycloplegic and noncycloplegic Plusoptix A12C measurements and autorefractometer with cycloplegia (CA) were compared. The spherical equivalent (SE) differences between CA and noncycloplegic Plusoptix A12C measurements (NPO) with CA and cycloplegic Plusoptix A12C measurements (CPO) were compared with axial length (AL), anterior chamber depth (ACD), corneal radius of curvature (CR), mean keratometry (meanK) and axial length/corneal radius of curvature ratio (AL/CR) values. The relationships between these were examined.

RESULTS

According to amblyopia risk factors (ARFs) based on the criteria in the 2013 AAPOS guidelines, 33 eyes (13%) in the NPO results and 34 eyes (13.6%) in the CPO results were found to be at risk for amblyopia. According to the CA results, the NPO had 67.3% sensitivity and 94.5% specificity, and the CPO 69.4% sensitivity and 89.1% specificity in detecting the values of refractive amblyopia factors determined by the AAPOS. In regard to refraction values determined by the AAPOS for amblyopia, according to CA results, the NPO had 71.4% sensitivity and 88.4% specificity in detecting myopia; 33.3% sensitivity and 93.6% specificity in detecting hyperopia; and 79.4% specificity and 71.2% sensitivity in detecting astigmatism. With regard to refraction values determined by the AAPOS for amblyopia, according to CA results, the CPO had 80.9% sensitivity and 90% specificity in detecting myopia; 13.3% sensitivity and 89.2% specificity in detecting hyperopia; and 44.9% sensitivity and 30.8% specificity in detecting astigmatism. When the SE differences between the CA and NPO values were compared with biometric parameters, a negative correlation was observed with ACD, AL, and especially AL/CR ratio.

CONCLUSION

Both the NPO and CPO showed moderate sensitivity and high specificity in detecting ARFs based on the criteria in the 2013 AAPOS guidelines. Sensitivity for detecting hyperopic risk factors was lower than for myopia and astigmatism. The CPO has no additional clinical advantage. A negative correlation was found between biometric parameters and NPO results. Thus, the NPO is more reliable in myopic children with higher axial lengths, deeper anterior chambers, and increased AL/CR ratios.

Development of Refractive Parameters in 3- to 6-Year-Old Children and Its Application in Myopia Prediction and Intervention Guidance

OBJECTIVE

To investigate refractive development and prevalence of myopia in children aged 3-6 years in Hebei Province, China, and to explore the developmental law of refraction, so as to clinically guide the prediction and intervention of myopia.

METHODS

In May 2019, a total of 6120 people were inspected in 68 kindergartens in 11 cities in Hebei Province. Child refractive refraction was checked under noncycloplegia using a handheld binocular vision screener (SW-800, SUOER, Tianjin, China). Axial length (AL) and corneal radius of curvature (CR) were measured using an ocular biometry (IOLMaster 500, Carl Zeiss, Germany). Myopia was defined as spherical equivalent (SE) ≤ -0.75 D.

RESULTS

A total of 5506 children aged 3-6 years met the criteria and were included in the statistical analysis. The prevalence of myopia was 3.49% (1.93% at age 3, 2.90% at age 4, 3.78% at age 5, and 3.88% at age 6). Overall, the mean SE was +0.67 ± 1.05 D (+0.81 ± 1.00 D at age 3, +0.79 ± 1.05 D at age 4, +0.67 ± 1.08 D at age 5, and +0.13 ± 1.01 D at age 6); the mean CR was 7.76 ± 0.26 mm (7.78 ± 0.26 mm at age3, 7.75 ± 0.25 mm at age 4, 7.77 ± 0.26 mm at age 5, and 7.76 ± 0.25 mm at age 6); the mean AL was 22.31 ± 0.73 mm (21.98 ± 0.63 mm at age 3, 22.12 ± 0.69 mm at age 4, 22.34 ± 0.73 mm at age 5, and 22.49 ± 0.73 mm at age 6).

CONCLUSIONS

Prevalence of myopia increases with age in children aged 3-6 years in Hebei, China. With the increase of age, CR is basically stable, and AL increases gradually. AL/CR, which is closely related to SE, can be used as an indicator to predict myopia and guide clinical work.

Lag of accommodation predicts clinically significant change of spherical equivalents after cycloplegia

AIM

To evaluate related factors with the change of spherical equivalents (ΔSE) and determine the suitable predictor of clinically significant ΔSE (≥0.50 D) with cyclopentolate hydrochloride on Chinese children.

METHODS

A total of 145 right eyes of 145 children aged 4 to 15y were enrolled. Intraocular pressure, axial length and lag of accommodation (LOA) were assessed before cycloplegia induced by 3 drops of 1% cyclopentolate at 5-minute intervals. SE was measured before and 1h after the first drop of cyclopentolate. ΔSE was compared between different gender groups and among refractive groups. Multivariate linear regression analysis was performed to find related factors with ΔSE. ROC analysis was used to figure out the suitable predictor of clinically significant ΔSE.

RESULTS

For the total 145 eyes, the mean SE reached up to -0.70±1.86 D from -1.30±1.62 D, with the mean ΔSE of 0.60±0.55 D. The mean ΔSE were 0.63±0.55 D and 0.57±0.56 D respectively in the male and female group (P=0.40). The mean ΔSE was significantly different among different refractive groups (P<0.0001), with the ΔSE of hyperopia group (1.12±0.64 D) larger than that of the emmetropia (0.56±0.43 D, P=0.001) and myopia group (0.32±0.28 D, P<0.0001). The ΔSE was correlated with LOA (B=-0.54, P<0.0001), cycloplegic SE (B=0.10, P<0.0001) and age (B=-0.04, P=0.015). ROC curve indicated that LOA predicted clinically significant ΔSE by 82% [area under the curve (AUC)=0.82] alone, while the value was slightly improved to 85% (AUC=0.85) in combination with axial length and 86% (AUC=0.86) in association with axial length as well as age.

CONCLUSION

After cycloplegia with cyclopentolate, the ΔSE decreases with larger LOA, longer axial length and older age. Specifically, LOA plays a more vital role in predicting clinically significant ΔSE.

A randomized clinical trial using cyclopentolate and tropicamide to compare cycloplegic refraction in Chinese young adults with dark irises

BACKGROUND

To evaluate the necessity of cycloplegia for epidemiological studies of refraction in Chinese young adults (aged 17-22 years) with dark irises, and to compare the cycloplegic effects of 1% cyclopentolate and 0.5% tropicamide in them.

METHODS

A total of 300 young adults (108 males and 192 females) aged 17 to 22 years (mean 19.03 ± 1.01) were recruited from Tianjin Medical University from November 2019 to January 2020. Participants were randomly divided into two groups. In the cyclopentolate group, two drops of 1% cyclopentolate eye drop were administrated (one drop every 5 min), followed by autorefraction and subjective refraction 30 to 45 min later. In the tropicamide group, four drops of 1% Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) eye drop were given (one drop every 5 min), followed by autorefraction and subjective refraction 20 to 30 min later. The participants and the examiners were masked to the medication. Distance visual acuity, intraocular pressure (IOP), non-cycloplegic and cycloplegic autorefraction (Topcon KR-800, Topcon Co. Tokyo, Japan), non-cycloplegic and cycloplegic subjective refraction and ocular biometry (Lenstar LS-900) were performed.

RESULTS

The values of spherical equivalent (SE) and sphere component were significantly different before and after cycloplegia in the cyclopentolate group and the tropicamide group (p < 0.05). The mean difference between noncycloplegic and cycloplegic autorefraction SE was 0.39 D (±0.66 D) in the cyclopentolate group and 0.39 D (±0.34 D) in the tropicamide group. There was no significant difference in the change of SE and sphere component after cycloplegia between the cyclopentolate group and the tropicamide group (p > 0.05). In each group, no significant difference was found between autorefraction and subjective refraction after cycloplegia (p > 0.05). We also found that more positive or less negative cycloplegic refraction was associated with the higher difference in SE in each group.

CONCLUSIONS

Cycloplegic refractions were generally more positive or less negative than non-cycloplegic refractions. It is necessary to perform cycloplegia for Chinese young adults with dark irises to obtain accurate refractive errors. We suggest that cycloplegic autorefraction using tropicamide may be considered as a reliable method for epidemiological studies of refraction in Chinese young adults with dark irises.

TRIAL REGISTRATION

The study was registered on September 7, 2019 (Registration number: ChiCTR1900025774 ).

Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

IMI 2021 Reports and Digest - Reflections on the Implications for Clinical Practice

The International Myopia Institute's (IMI) mission is to advance research, education, and management of myopia to decrease future vision impairment and blindness associated with increasing myopia. Its approach is to bring together scientists, clinicians, policymakers, government members, and educators into the field of myopia to stimulate collaboration and sharing of knowledge. The latest reports are on pathologic myopia, the impact of myopia, risk factors for myopia, accommodation and binocular vision in myopia development and progression, and the prevention of myopia and its progression. Together with the digest updating the 2019 International Myopia Institute white papers using the research published in the last 18 months, these evidence-based consensus white papers help to clarify the imperative for myopia control and the role of environmental modification initiatives, informing an evidence-based clinical approach. This guidance includes who to treat and when to start or stop treatment, and the advantages and limitations of different management approaches.

Agreement Between Retinoscopy, Autorefractometry and Subjective Refraction for Determining Refractive Errors in Congolese Children

OBJECTIVE

To assess the agreement between retinoscopy and autorefractometry and between subjective refraction and both retinoscopy and autorefractometry in Congolese children.

PATIENTS AND METHODS

Fifty-four children (6-17 years old) were enrolled consecutively in this cross-sectional study. Refraction was evaluated before and after cycloplegia (1% cyclopentolate) with retinoscopy and autorefractometry. Readings were compared (paired t-test) and agreement assessed with Bland-Altman plots. Subjective refraction was compared with the two methods to determine which one provides better reference estimates for subjective refraction.

RESULTS

Under cycloplegia, the spherical power was comparable between retinoscopy and autorefractometry (1.12 ± 1.37 D vs 1.22 ± 1.06D, P = 0.70), cylinder power was significantly more myopic on retinoscopy than autorefractometry (0.80 ± 1.10D vs -0.62 ± 0.66, P = 0.019), and SE was greater on autorefractometry than retinoscopy (0.91 ± 1.10D vs 0.72 ± 1.00D, P = 0.014). Retinoscopy and autorefractometry overestimated the power of spherical (P = 0.022 and 0.002, respectively) and cylindrical components (all P < 0.001). There was an agreement between retinoscopy and autorefractometry in measuring spherical (bias: 0.09 ± 0.16D; limit of agreement, LoA: -0.40 to 0.22D) and cylindrical power (bias: -0.18 ± 0.20D; LoA: -0.57 to 0.21D). Subjective refraction agreed with cycloplegic retinoscopy for determining SE power (bias: 0.11D; LoA: -0.51 to 0.73D).

CONCLUSION

Retinoscopy and autorefractometry can be used interchangeably in children for determining the power of spherical and cylindrical components. Cycloplegic retinoscopy is better than autorefractometry to obtain SE reference values for subjective refraction in children.

Refractive Error in Chinese Preschool Children: The Shanghai Study

Purpose:

To examine the prevalence of refractive error and some associated factors in Chinese preschool children.

Methods:

The Jinshan District Eye Study was a school-based survey of eye health in a large sample of 4- to 6-year-olds attending kindergartens from May 2013 to December 2013 in Shanghai. Refractive error was measured using an autorefractor under noncycloplegic conditions. Axial length (AL) was measured with an ocular biometry system. In addition, body height and weight were also recorded.

Results:

A total of 7,166 children successfully completed their refraction measurements. The median (interquartile range) of spherical equivalent (SE) for all the children was +0.25 D (−0.13 D to +0.62 D), and the range was −15.88 to +18.13 D. The mean AL for all the children was 22.35±0.70 mm, and the range was 18.20 to 27.71 mm. The overall prevalence of myopia (−1.00 D or less), hyperopia (+2.00 D or greater), and astigmatism (1.00 D or greater) were 5.9%, 1.0%, and 12.7%, respectively. After multivariate analysis, more myopic SE (or less hyperopic SE) was significantly associated with girls, longer AL, taller, and lighter.

Conclusion:

Shanghai has a high prevalence of refractive error in the world. However, longitudinal studies are needed to evaluate refractive changes over time in individual children and warranted to prevent the development of myopia.

Correlation analysis and multiple regression formulas of refractive errors and ocular components

The multiple regression formulas and correlation of ocular components with refractive errors are presented by Gaussian optics. The refractive error changing rate for the cornea and lens power, the axial length, anterior chamber depth (ACD) and vitreous chamber depth (VCD) are calculated, including nonlinear terms for more accurate rate functions than the linear theory. Our theory, consistent with the empirical data, shows that the Pearson correlation coefficients for spherical equivalent (SE) and ocular components are highest for SE with axial length, ACD and VCD and weakest for corneal power, lens power and lens thickness. Moreover, our regression formulas show the asymmetric feature of the correlation that the axial length, ACD and VCD are more strongly correlated (with higher negative regression constants) with refractive errors in eyes with hyperopia than in eyes with myopia, particularly for severe hyperopia.

Cycloplegia and spectacle prescribing in children: attitudes of UK optometrists

PURPOSE

To survey a large number of UK-based optometrists, in a variety of settings, to determine current attitudes relating to the use of cycloplegia and spectacle prescribing in children aged ≤11 years.

METHODS

One thousand randomly selected members of the College of Optometrists (UK) were invited to complete an electronic questionnaire. The questionnaire was comprised of 42 questions relating to respondent demographics, practitioner use of cycloplegia and attitudes to using cycloplegia to assess childhood refractive error and prescribing spectacles for children aged ≤11 years.

RESULTS

Three hundred and eleven practitioners (31%) completed the questionnaire. Practitioners agreed that they are confident carrying out cycloplegic refraction (60%) and instilling cyclopentolate (77%); are not concerned about the time the procedure takes (69%); feel parents are receptive to its use (65%) and are not discouraged by side effects (72%). Most practitioners agreed that they would carry out a cycloplegic refraction in pre-school children (aged 2-4 years) at their first eye exam (34% vs 27%), but would not carry out a cycloplegic refraction in a child of school age (5-7 years: 25% vs 47%, 8-11 years: 12% vs 45%). More recently qualified practitioners are more likely to be proactive in using cycloplegia (Mann-Whitney, p = 0.003). Community practitioners prescribed at slightly lower levels of ametropia in non-strabismic children than those working in a hospital setting both in the present study and in comparison to previously published hospital optometry values, particularly for hyperopia at 1 year of age.

CONCLUSIONS

This is the first study to report practitioner use of cycloplegia and attitudes to using cycloplegia to assess childhood refractive error and prescribing spectacles for children in a large number of UK-based optometrists practising in a variety of settings. The majority of practitioners responded in a positive manner to the use of cycloplegia and reported patterns of use which adhere closely to available professional guidance. However, outcomes indicate practitioners may appreciate more comprehensive evidence-based resources to inform their decision-making relating to use of cycloplegia in paediatric examination.

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.

Accuracy of noncycloplegic refraction performed at school screening camps

Purpose:

The aim of this study was to compare noncycloplegic refraction performed in school camp with that performed in eye clinic in children aged 6–16 years.

Methods:

A prospective study of children with unaided vision <0.2 LogMAR who underwent noncycloplegic retinoscopy (NCR) and subjective refraction (SR) in camp and subsequently in eye clinic between February and March 2017 was performed. A masked optometrist performed refractions in both settings. The agreement between refraction values obtained at both settings was compared using the Bland–Altman analysis.

Results:

A total of 217 eyes were included in this study. Between the school camp and eye clinic, the mean absolute error ± standard deviation in spherical equivalent (SE) of NCR was 0.33 ± 0.4D and that of SR was 0.26 ± 0.5D. The limits of agreement for NCR were +0.91D to − 1.09D and for SR was +1.15D to -1.06D. The mean absolute error in SE was ≤0.5D in 92.62% eyes (95% confidence interval 88%–95%).

Conclusion:

A certain degree of variability exists between noncycloplegic refraction done in school camps and eye clinic. It was found to be accurate within 0.5D of SE in 92.62% eyes for refractive errors up to 4.5D of myopia, 3D of cylinder, and 1.5D of hyperopia.

Cycloplegic refraction by 1% cyclopentolate in young adults: is it the gold standard? The Anyang University Students Eye Study (AUSES)

AIMS

To document the difference between non-cycloplegic and cycloplegic refraction and explore its associated factors in Chinese young adults.

METHODS

A school-based study including 7971 undergraduates was conducted in Anyang, Henan Province, China. Cycloplegia was achieved with two drops of 1% cyclopentolate and 1 drop of Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) with a 5 min interval. Non-cycloplegic and cycloplegic refractions were measured by an autorefractor. A paired-sample t-test and Spearman correlation analysis were used for analysis with data from only the right eyes included.  RESULTS: Of the 7971 students examined, 7793 (97.8%) with complete data were included, aging 20.2±1.5 years. Male students accounted for 36.8%. Overall, there was a significant difference between non-cycloplegic and cycloplegic SE (spherical equivalent) of 0.83±0.81D (p<0.01). The difference was 1.80±1.11D, 1.26±0.93D and 0.69±0.69D for those with cycloplegic hyperopia, emmetropia and myopia, respectively (p<0.01 for all). Those with a hyperopic shift less than 0.25D and 0.5D accounted for 11.1% and 34.1%, respectively. A significant relationship was found between difference in SE and cycloplegic refraction (r=0.33, b=0.11, p<0.01). Without cycloplegia, prevalence of hyperopia and emmetropia would be underestimated by 6.2% (1.0% vs 7.2%) and 5.7% (3.8% vs 9.5%), respectively, with prevalence of myopia and high myopia overestimated by 12.1% (95.3% vs 83.2%) and 6.1% (17.2% vs 11.1%).  CONCLUSION: Lack of cycloplegia will lead to significant misclassification of myopia, emmetropia and hyperopia in Chinese young adults. Cycloplegia is therefore essential for this age-group in epidemiological studies.

Global and regional estimates of prevalence of refractive errors: Systematic review and meta-analysis

Purpose

The aim of the study was a systematic review of refractive errors across the world according to the WHO regions.

Methods

To extract articles on the prevalence of refractive errors for this meta-analysis, international databases were searched from 1990 to 2016. The results of the retrieved studies were merged using a random effect model and reported as estimated pool prevalence (EPP) with 95% confidence interval (CI).

Results

In children, the EPP of myopia, hyperopia, and astigmatism was 11.7% (95% CI: 10.5–13.0), 4.6% (95% CI: 3.9–5.2), and 14.9% (95% CI: 12.7–17.1), respectively. The EPP of myopia ranged from 4.9% (95% CI: 1.6–8.1) in South–East Asia to 18.2% (95% CI: 10.9–25.5) in the Western Pacific region, the EPP of hyperopia ranged from 2.2% (95% CI: 1.2–3.3) in South-East Asia to 14.3% (95% CI: 13.4–15.2) in the Americas, and the EPP of astigmatism ranged from 9.8% in South-East Asia to 27.2% in the Americas. In adults, the EPP of myopia, hyperopia, and astigmatism was 26.5% (95% CI: 23.4–29.6), 30.9% (95% CI: 26.2–35.6), and 40.4% (95% CI: 34.3–46.6), respectively. The EPP of myopia ranged from 16.2% (95% CI: 15.6–16.8) in the Americas to 32.9% (95% CI: 25.1–40.7) in South-East Asia, the EPP of hyperopia ranged from 23.1% (95% CI: 6.1%–40.2%) in Europe to 38.6% (95% CI: 22.4–54.8) in Africa and 37.2% (95% CI: 25.3–49) in the Americas, and the EPP of astigmatism ranged from 11.4% (95% CI: 2.1–20.7) in Africa to 45.6% (95% CI: 44.1–47.1) in the Americas and 44.8% (95% CI: 36.6–53.1) in South-East Asia. The results of meta-regression showed that the prevalence of myopia increased from 1993 (10.4%) to 2016 (34.2%) (P = 0.097).

Conclusion

This report showed that astigmatism was the most common refractive errors in children and adults followed by hyperopia and myopia. The highest prevalence of myopia and astigmatism was seen in South-East Asian adults. The highest prevalence of hyperopia in children and adults was seen in the Americas.

Changes in the anterior segment after cycloplegia with a biometer using swept-source optical coherence tomography

The aim of this study was to investigate changes in the anterior segment of the eye after cycloplegia. A biometer combined with swept-source optical coherence tomography (SSOCT) was used for measurements. Patients with strabismus or amblyopia who underwent cycloplegia were included. The axial length, central corneal thickness, anterior chamber depth, and lens thickness were measured with the biometer-SSOCT system before and after cycloplegia. Altogether, 10 eyes of 10 patients (mean age 7.20 ± 3.08 years, range 4-14 years) were evaluated. The mean measurements before cycloplegia were 22.75 ± 0.96 mm axial length, 516 ± 33 μm central corneal thickness, 3.40 ± 0.21 mm anterior chamber depth, and 3.77 ± 0.26 mm lens thickness. The corresponding values after cycloplegia were 22.75 ± 0.95 mm, 519 ± 34 μm, 3.68 ± 0.16 mm, and 3.42 ± 0.20 mm, respectively. The mean lens thickness had significantly decreased (P < 0.001) after cycloplegia, and the mean anterior chamber depth had significantly increased (P < 0.001). The means of the axial length (P = 0.66) and central corneal thickness (P = 0.17) had not changed significantly. The change in lens thickness was significantly correlated with the change in anterior chamber depth (r = -0.73, P = 0.02). The new biometer-SSOCT combination proved useful for accurately detecting changes in the anterior segment of the eye after cycloplegia in pediatric patients. The biometer's measurements indicated increased anterior chamber depth and decreased lens thickness after cycloplegia. The anterior chamber depth increased relative to the decrease in lens thickness.