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 International Myopia Institute introduced the concept of \"pre-myopia\" in 2019, defining it as children with refractive error ≤+0.75 D and >-0.50 D. By considering baseline refractive error, age, and other quantifiable risk factors, there is a significant likelihood that individuals falling into this category may develop myopia in the future. Therefore, it is deemed worthwhile to implement preventative intervention measures.This article delves into the epidemiology of premyopia in children and adolescents, the criteria for determining pre-myopia, the characteristics of refractive changes, and the existing evidence gaps in pre-myopia control technology. Furthermore, it explores the role and advantages of implementing pre-myopia control to enhance efforts in preventing and managing myopia. The paper highlights the essential value and future trajectory of pre-myopia control in the comprehensive management of myopia. The ultimate goal is to foster collaboration with professionals, aiming to discuss innovative strategies for effectively preventing and managing the onset and progression of myopia.
国际近视眼研究院在2019年提出了“近视眼前期”的概念，将其定义为儿童眼屈光度数≤+0.75 D且>-0.50 D，结合基线屈光度数、年龄和其他可量化危险因素，有较大可能在未来发展为近视眼，故值得采取预防性干预措施。本文从近视眼前期在儿童青少年中的流行病学特征、近视眼前期的判断标准和屈光变化特点、针对近视眼前期防控技术已有的和尚缺的研究证据、开展近视眼前期防控对促进近视眼防控关口前移的作用与收益4个方面，阐述儿童近视眼前期防控在近视眼综合防治中的重要价值和未来方向，以期和专业同道共同探讨有效防控近视眼发生发展的新策略。.

OBJECTIVE: To investigate the correlation of angles α and κ with the refractive and biological parameters in children.
METHODS: This case-series study included 438 eyes of 219 children (males/females = 105/114, age: 3-15 years). Ocular biometric parameters, including axial length, corneal radius of curvature (CR), white-to-white distance (WTW), angle κ and angle α, were measured using IOL Master 700; auto-refraction were assessed under cycloplegia. The eyes were assigned to different groups based on CR, WTW, and gender to compare the angles α and κ, and analyze the correlations between the differences of biological parameters on angles α and κ.
RESULTS: The means of axial length, CR, WTW, angle α, and angle κ were 23.24 ± 1.14 mm, 7.79 ± 0.27 mm, 11.68 ± 0.41 mm, 0.45 ± 0.25 mm, and 0.27 ± 0.22 mm, respectively. Angle α was correlated with CR and WTW (fixed effect coefficient [FEC] = 0.237, p = 0.015; FEC = -0.109, p = 0.003; respectively), and angle κ also correlated with CR and WTW (FEC = 0.271, p = 0.003; FEC = -0.147, p < 0.001, respectively). Comparing subgroups, the large CR and small WTW group had larger angles α (0.49 ± 0.27 vs. 0.41 ± 0.21, p < 0.001; 0.46 ± 0.27 vs. 0.44 ± 0.21, p < 0.05, respectively) and κ (0.29 ± 0.25 vs. 0.24 ± 0.15, p < 0.01; 0.29 ± 0.25 vs. 0.26 ± 0.19, p < 0.05, respectively). The differences in interocular angles α and κ showed correlation with interocular WTW (r = - 0.255, p < 0.001; r = - 0.385, p < 0.001). Eyes with smaller WTW tended to have larger angle κ (0.28 ± 0.27 vs. 0.25 ± 0.15, p < 0.05).
CONCLUSIONS: The size of angle α/κ may be correlated to CR and WTW, and a larger WTW eye may suggest a smaller angle κ compared with the fellow eye.

UNASSIGNED: To evaluate the longitudinal changes in subfoveal choroidal thickness (SFCT) in children with different refractive status.
UNASSIGNED: A total of 2290 children 3 to 14 years old who attended the first year of kindergarten (G0), first year of primary school (G1), fourth year of primary school (G4), or first year of junior high school (G7) in Guangzhou, China, were recruited and followed up for 2 years. All participants received cycloplegic autorefraction, axial length measurement and SFCT measurement using a CIRRUS HD-OCT device. Children were divided into groups of persistent non-myopia (PNM), persistent myopia (PM), or newly developed myopia (NDM). Children in the PNM and PM groups were further divided into subgroups of stable refraction (absolute mean annual spherical equivalent refraction [SER] change < 0.5 D) and refractive progression (absolute mean annual SER change ≥ 0.5 D).
UNASSIGNED: The mean ± SD ages for the G1 to G7 cohorts were 3.89 ± 0.30, 6.79 ± 0.47, 9.71 ± 0.34, and 12.54 ± 0.38, years, respectively. SFCT consistently decreased in the NDM group across the G1 to G7 cohorts (all P < 0.001) and exhibited variability across different age cohorts in the PNM and PM groups. Further subgroup analysis revealed significant thickening of SFCT in the PNM-stable group among the G0, G1, and G7 cohorts (all P < 0.05), whereas it remained stable among all cohorts in the PM-stable group (all P > 0.05). Conversely, SFCT exhibited thinning in the G4 and G7 cohorts in the PM-progressive group (both P < 0.01) and for the entire cohort of children in the PNM-progressive group (P = 0.012).
UNASSIGNED: SFCT increased in nonmyopic children with stable refraction, remained stable in myopic children maintained stable refraction, and decreased in those with refractive progression, whether they were myopic or not.

OBJECTIVE: To investigate the capacity of critical flicker frequency (CFF) in discriminating cataract eyes with or without macula disease using trichromatic flickers, and to develop a model to predict postoperative best corrected visual acuity (BCVA).
METHODS: Patients were divided into two groups based on the presence or absence of macular disease. CFF threshold measurements of red (R-CFF), green (G-CFF), and yellow (Y-CFF) flickers were conducted both preoperatively and postoperatively. A generalized estimating equations model (GEE) was employed to examine the relationship between CFF threshold and 3-month postoperative BCVA.
RESULTS: A total of 115 eyes were enrolled, with 59 eyes in the cataract alone group and 56 eyes in the cataract with macular disease group completing the follow-up. R-CFF was found to be consistent before and after cataract removal (P = 0.06), even in cases where OCT was not performed successfully (P > 0.05). Y-CFF showed the highest AUC (0.798) for differentiating ocular comorbidities. According to the GEE model, in patients with a CFF threshold below 26 Hz, the odds ratios for achieving a postoperative VA of 20/40 or better were 34.8% for R-CFF, 26.0% for G-CFF, and 24.5% for Y-CFF.
CONCLUSIONS: CFF emerges as a promising tool for predicting postoperative BCVA, providing valuable supplementary insights when fundus examination is obstructed. R-CFF demonstrates the best resistance to cataracts, while Y-CFF exhibits the highest sensitivity both in identifying macular diseases and predicting postoperative BCVA of 20/40 or better.

The purpose of this study is to examine the viability, precision, and consistency of a computer-based optokinetic nystagmus analyzer (nystagmus meter) for diagnosing eyesight in preschoolers. A total of 59 subjects who could pass the log of minimum angle of resolution (LogMAR) visual acuity chart were divided into three groups by age, 4-, 5-, and 6-year-old groups, and their visual acuity was tested with nystagmus meter. The percentage of children in each age group that could be detected by nystagmus was recorded along with the differences between these groups. The correlation between the test results from the two methods was found for each age group using the correlation coefficient method. Repeated measurements were used to assess the two visual acuity values of the measured nystagmus, and the repeatability of the two measurement techniques for different age groups was compared. The overall measurability of the visual acuity detected by nystagmus was 93.22%, and the measurability of the 4-, 5-, and 6-year-old groups was 90%, 95%, and 94.74%, respectively. There was no statistically significant difference in the measurability of subjects among all age groups (P = 1.0). The outcomes of the LogMAR visual acuity chart had a negative correlation with the visual acuity measured by the nystagmus meter. The overall correlation coefficient R value was -0.80, and the correlation coefficient R value of the 4-, 5-, and 6-year-old groups was -0.79, -0.76, and -0.87, respectively. The nystagmus meter has good feasibility, accuracy, and stability in visual acuity testing and can be used for visual acuity testing in children.

The development trajectories of children\'s SER remain unknown. This study aimed to characterize spherical equivalent refraction (SER) trajectories during grades 1-4 in Chinese children.
This prospective cohort study included 1226 first-grade non-myopic children from 12 public primary schools, randomly selected in two districts in Guangzhou, China. From November 2018 to March 2022, four-wave ocular examinations and questionnaire surveys have been completed. The group-based trajectory modeling was used to explore SER trajectories in grades 1-4.
All five trajectories showed an upward trend and rose faster after grade 2. Children in the sharp-developing (n = 44), high-developing (n = 136), and rapid-developing (n = 237) myopia groups developed myopia before grades 2, 3, and 4, respectively. Their SER development speed remained at a relatively high level after myopia, almost consistent with that before myopia. Children in the moderate-developing (n = 418) and low-developing (n = 391) non-myopia groups did not develop myopia before grade 4. Some characteristics in grade 1 were independently associated with SER trajectories, including sex, axial length, number of parents with myopia, residence, academic achievement, and the duration of outdoor activity. Based on the baseline characteristics, we established the model predicting the probability of children belonging to each group.
Myopia interventions are best started in grade 1 or preschool age. If interventions are not taken in time, the latest intervention window might be in grades 1, 2, and 3 for children with a high probability of belonging to the sharp-developing, high-developing, and rapid-developing myopia groups, respectively. The above probabilities might be predicted using the model we established. Moreover, the interventions for myopic children shouldn\'t be ignored.

OBJECTIVE: To investigate fundus tessellation density (TD) and its association with axial length (AL) elongation and spherical equivalent (SE) progression in children.
METHODS: The school-based prospective cohort study enrolled 1,997 individuals aged 7 to 9 years in 11 elementary schools in Mojiang, China. Cycloplegic refraction and biometry were performed at baseline and 4-year visits. The baseline fundus photographs were taken, and TD, defined as the percentage of exposed choroidal vessel area in the photographs, was quantified using an artificial intelligence-assisted semiautomatic labeling approach. After the exclusion of 330 ineligible participants because of loss to follow-up or ineligible fundus photographs, logistic models were used to assess the association of TD with rapid AL elongation (>0.36 mm/year) and SE progression (>1.00 D/year).
RESULTS: The prevalence of tessellation was 477 of 1,667 (28.6%) and mean TD was 0.008 ± 0.019. The mean AL elongation and SE progression in 4 years were 0.90 ± 0.58 mm and -1.09 ± 1.25 D. Higher TD was associated with longer baseline AL (β, 0.030; 95% confidence interval: 0.015-0.046; P < 0.001) and more myopic baseline SE (β, -0.017; 95% confidence interval: -0.032 to -0.002; P = 0.029). Higher TD was associated with rapid AL elongation (odds ratio, 1.128; 95% confidence interval: 1.055-1.207; P < 0.001) and SE progression (odds ratio, 1.123; 95% confidence interval: 1.020-1.237; P = 0.018).
CONCLUSIONS: Tessellation density is a potential indicator of rapid AL elongation and refractive progression in children. TD measurement could be a routine to monitor AL elongation.

To investigate changes in peripheral eye length (PEL) and peripheral refraction (PR) in myopic children after wearing spectacle lenses with highly or slightly aspherical lenslets (HAL or SAL) for 2 years.
We recruited 170 children aged 8 to 13 years with myopia between -0.75 diopters (D) and -4.75 D. Participants were randomized to wear HAL, SAL, or single vision spectacle lenses (SVL). PEL and PR were measured at 0° central and 15° and 30° in the nasal and temporal retina every 6 months for 2 years. The relative PR (RPR) was calculated by subtracting central from peripheral values.
PELs significantly increased with time (all P < 0.001), with the greatest elongation in the SVL group and the least in the HAL group. In the SVL and SAL groups, axial length elongated faster than the periphery. Whereas in the HAL group, N30 elongated faster than other PELs, axial length elongated less than the periphery. With time, the PR became more negative (all P < 0.001), with the most negative changes in the SVL group and the least negative changes in the HAL group. RPR became more hyperopic in the SVL and SAL groups, but less hyperopic in the HAL group (all P < 0.001).
Over the 2-year myopia progression, steeper retina and greater peripheral hyperopic defocus were found in the SVL group. In the SAL group, changes were attenuated. In the HAL group, the retina flattened and peripheral defocus became less hyperopic.
HAL and SAL lenses had little impact on PEL elongation.

Stereopsis is the ability to perceive depth using the slightly different views from two eyes. This study aims to conduct innovative stereopsis tests using the objective data outputted by eye tracking technology.
A laptop and an eye tracker were used to establish the test system. Anaglyphic glasses were employed to execute the stereopsis assessment. The test symbol employed was devised to emulate the quantitative measurement component of the Random Dot 3 Stereo Acuity Test. Sub-pixel technology was used to increase the disparity accuracy of test pages. The tested disparities were: 160″, 100″, 63″, 50″, 40″, 32″, 25″, 20″, 16″, and 12.5″. The test was conducted at a distance of 0.65m. Conventional and eye tracking stereopsis assessments were conducted on 120 subjects. Wilcoxon signed-rank test was used to test the difference, while the Bland-Altman method was used to test the consistency between the two methods.
The Wilcoxon signed-rank test showed no significant difference between conventional and eye tracking thresholds of stereopsis (Z = -1.497, P = 0.134). There was a high level of agreement between the two methods using Bland- Altman statistical analysis (The 95 per cent limits of agreement were -0.40 to 0.47 log arcsec).
Stereoacuity can be evaluated utilizing an innovative stereopsis measurement system grounded in eye tracking technology.