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.

Evaluating the impact of COVID-19 pandemic-related home confinement on the refractive error of school-aged children in Germany: a cross-sectional study based on data from 414 eye care professional centres.

OBJECTIVE: This study aimed at evaluating refractive changes in German school-aged children before and after the COVID-19 pandemic. DESIGN: Cross-sectional study. SETTING: 414 eye care professional centres from Germany. PARTICIPANTS: Refractive data from 59 926 German children aged 6-15 years were examined over a 7-year period (2015-2021). PRIMARY AND SECONDARY OUTCOME MEASURES: Spherical equivalent refraction was assessed as a function of year, age and gender. The refractive values concerning 2020 and 2021 were compared with those assigned to prior years (2015-2019). RESULTS: The refractive data associated with 2020 and 2021 showed a myopic refractive shift of approximately -0.20D compared with the 2015-2019 range. The refractive change was statistically considerable in the 6 to 11-year range (p<0.05), while from 12 to 15 years was negligible (p≥0.10). Percentage of myopes was also impacted in 2021 (p=0.002), but not in 2020 (p=0.25). From 6 to 11 years, the percentage of myopes in 2021 increased significantly by 6.02% compared with the 2015-2019 range (p≤0.04). The highest percentage increase occurred at 8 and 10 years of age, showing a rise of 7.42% (p=0.002) and 6.62% (p=0.005), respectively. From 12 to 15 years, there was no significant increase in the percentage of myopes in 2021 (p≥0.09). Percentage of myopes in 2020 was not influenced at any age (p≥0.06). CONCLUSION: Disruption of normal lifestyle due to pandemic-related home confinement appears to lead to a myopic refractive shift in children aged 6-11 years in Germany. The greater effect observed at younger ages seems to emphasise the importance of refractive development in this age group.

Prediction of refractive error and its progression: a machine learning-based algorithm.

OBJECTIVE: Myopia is the refractive error that shows the highest prevalence for younger ages in Southeast Asia and its projection over the next decades indicates that this situation will worsen. Nowadays, several management solutions are being applied to help fight its onset and development, nonetheless, the applications of these techniques depend on a clear and reliable assessment of risk to develop myopia. METHODS AND ANALYSIS: In this study, population-based data of Chinese children were used to develop a machine learning-based algorithm that enables the risk assessment of myopia's onset and development. Cross-sectional data of 12 780 kids together with longitudinal data of 226 kids containing age, gender, biometry and refractive parameters were used for the development of the models. RESULTS: A combination of support vector regression and Gaussian process regression resulted in the best performing algorithm. The Pearson correlation coefficient between prediction and measured data was 0.77, whereas the bias was -0.05 D and the limits of agreement was 0.85 D (95% CI: -0.91 to 0.80D). DISCUSSION: The developed algorithm uses accessible inputs to provide an estimate of refractive development and may serve as guide for the eye care professional to help determine the individual best strategy for management of myopia.

Clinical Evaluation of MyoCare in Europe (CEME): study protocol for a prospective, multicenter, randomized, double-blinded, and controlled clinical trial.

BACKGROUND: Myopia prevalence has been increasing in the last decades, and its pathological consequences, including myopic maculopathy and high myopia-associated optic neuropathy, are now one of the most common causes of visual impairment. It is estimated that by 2050, more than 50% of Europeans and Americans will be myopes, which is alarming due to the high morbidity of myopes over - 6.00D. Once myopia has appeared, there are different options with scientific evidence to try to slow the axial length growth. Ophthalmic lenses are the less invasive treatment to control myopia, and there is evidence about the efficacy of different designs, mainly in the Asiatic population. However, new designs have been launched, and it is not known if efficacy is the same between Asiatic and European subjects. Thus, we have set up a randomized, controlled, double-blind, and multicenter trial to investigate the efficacy of a new design of ophthalmic lenses for myopia control in European children. METHODS: A 2-year prospective, multicenter, randomized controlled, and double-blind clinical trial is used to investigate the efficacy of a new design of ophthalmic lenses to slow the progression of myopia. Three hundred children aged from 6 to 13 years old will be recruited and randomly assigned to a study or control group. The study group will be composed of 150 children wearing MyoCare while the control group will be composed of 150 children wearing Clearview. The inclusion criteria will be myopia with a spherical equivalent between - 0.75D and - 5.00D, astigmatism < 1.50D, and anisometropia < 1.00D and having a historical evolution of at least - 0.50 The primary outcome is to compare the mean annual progression of the spherical equivalent between both groups. The secondary outcomes are axial length, choroidal thickness, phorias, and accommodative status of both groups. DISCUSSION: This study will be the first randomized and controlled clinical trial in European children with spectacle lenses based on simultaneous competing defocus. The results will shed light on the clinical evidence of spectacle lenses relying on this new design for the management of myopia with results of efficacy in the non-Asiatic population. TRIAL REGISTRATION: EU Clinical Trials Register (EudraCT) 2022-001696. Registered on 27 April 2022. CLINICALTRIALS: gov NCT05919654. Registered on 26 June 2023.

The Refractive Error and Vision Impairment Estimation with Spectacle Data Study.

Purpose: To investigate whether spectacle lens sales data can be used to estimate the population distribution of refractive error among patients with ametropia and hence to estimate the current and future risk of vision impairment. Design: Cross-sectional study. Participants: A total of 141 547 436 spectacle lens sales records from an international European lens manufacturer between 1998 and 2016. Methods: Anonymized patient spectacle lens sales data, including refractive error information, was provided by a major European spectacle lens manufacturer. Data from the Gutenberg Health Survey was digitized to allow comparison of a representative, population-based sample with the spectacle lens sales data. A bootstrap analysis was completed to assess the comparability of both datasets. The expected level of vision impairment resulting from myopia at 75 years of age was calculated for both datasets using a previously published risk estimation equation combined with a saturation function. Main Outcome Measures: Comparability of spectacle lens sales data on refractive error with typical population surveys of refractive error and its potential usefulness to predict vision impairment resulting from refractive error. Results: Equivalent estimates of the population distribution of spherical equivalent refraction can be provided from spectacle lens data within limits. For myopia, the population distribution was equivalent to the Gutenberg Health Survey (≤ 5% deviation) for levels of -2.0 diopters (D) or less, whereas for hyperopia, the distribution was equivalent (≤ 5% deviation) for levels of +3.0 D or more. The estimated rates of vision impairment resulting from myopia were not statistically significantly different (chi-square, 182; degrees of freedom, 169; P = 0.234) between the spectacle lens dataset and Gutenberg Health Survey dataset. Conclusions: The distribution of refractive error and hence the risk of vision impairment resulting from refractive error within a population can be determined using spectacle lens sales data. Pooling this type of data from multiple industry sources could provide a cost-effective, timely, and globally representative mechanism for monitoring the evolving epidemiologic features of refractive error and associated vision impairment.

Positions of the horizontal and vertical centre of rotation in eyes with different refractive errors.

PURPOSE: To determine how the position of the centre of rotation of the eyeball is related to axial length and refractive error when horizontal and vertical eye movements are performed. METHODS: A custom-built eye tracker was used that determined the centre of rotation of the eye (COR) from lateral displacements of the pupil centre. Horizontal and vertical eye movements were studied in the right eyes, and each measurement performed five times in 59 subjects (32 females) with an average age of 36.6 ± 9.1 years. Spherical equivalent refractive errors ranged from -9.7 to +6.8 D with an average error of -1.5 ± 2.9 D. Axial lengths were measured with the ZEISS IOL Master 500. RESULTS: The mean horizontal centre of rotation (COR) of the right eye for a saccade from 0° to ±11.9° was 15.3 ± 1.5 mm behind the corneal apex, while the average vertical COR for the same angle of eccentricity was 12.5 ± 1.4 mm, indicating that the horizontal COR was 2.8 ± 1.7 mm behind the vertical COR. In right eyes, horizontal COR was significantly correlated with axial length (r = 0.28, p = 0.02) but not with the spherical equivalent refractive error (r = 0.39, p = 0.90). Similarly, vertical COR was significantly correlated with axial length (r = 0.25, p = 0.03) but not with the spherical equivalent refractive error (r = 0.17, p = 0.90). CONCLUSIONS: While it might be expected that the COR is dependent on axial length, the correlation was not strong. Interestingly, the location of the COR was substantially different for horizontal and vertical eye movements which may relate to the flatter curvature of the eyeball in the vertical meridian, compared to the horizontal, as described in previous studies.

Development and Testing of a Compact Autorefractor Based on Double-Pass Imaging.

Autorefraction is an objective way to determine the refractive error of the eye, without the need for feedback by the patient or a well-educated practitioner. To make refractive measurements more accessible in the background of the growing prevalence of myopia, a compact autorefractor was built, containing only few optical components and relying on double-pass imaging and the physical properties of the point-spread function and digital image processing instead. A method was developed to analyze spherical defocus as well as the defocus and angle of astigmatism. The device was tested using calibrator eye models in a range of ± 15 D spherical defocus and -3 D astigmatic defocus. Reliable results could be achieved across the whole measurement range, with only a small increase in deviation toward high values of refractive errors, showing the feasibility of a PSF-based approach for a compact and low-cost solution for objective measurements of refractive error.

Application of big-data for epidemiological studies of refractive error.

PURPOSE: To examine whether data sourced from electronic medical records (EMR) and a large industrial spectacle lens manufacturing database can estimate refractive error distribution within large populations as an alternative to typical population surveys of refractive error. SUBJECTS: A total of 555,528 patient visits from 28 Irish primary care optometry practices between the years 1980 and 2019 and 141,547,436 spectacle lens sales records from an international European lens manufacturer between the years 1998 and 2016. METHODS: Anonymized EMR data included demographic, refractive and visual acuity values. Anonymized spectacle lens data included refractive data. Spectacle lens data was separated into lenses containing an addition (ADD) and those without an addition (SV). The proportions of refractive errors from the EMR data and ADD lenses were compared to published results from the European Eye Epidemiology (E3) Consortium and the Gutenberg Health Study (GHS). RESULTS: Age and gender matched proportions of refractive error were comparable in the E3 data and the EMR data, with no significant difference in the overall refractive error distribution (χ2 = 527, p = 0.29, DoF = 510). EMR data provided a closer match to the E3 refractive error distribution by age than the ADD lens data. The ADD lens data, however, provided a closer approximation to the E3 data for total myopia prevalence than the GHS data, up to age 64. CONCLUSIONS: The prevalence of refractive error within a population can be estimated using EMR data in the absence of population surveys. Industry derived sales data can also provide insights on the epidemiology of refractive errors in a population over certain age ranges. EMR and industrial data may therefore provide a fast and cost-effective surrogate measure of refractive error distribution that can be used for future health service planning purposes.

Comparison of Methods for Estimating Retinal Shape: Peripheral Refraction vs. Optical Coherence Tomography.

Retinal shape presents a clinical parameter of interest for myopia, and has commonly been inferred indirectly from peripheral refraction (PRX) profiles. Distortion-corrected optical coherence tomography (OCT) scans offer a new and direct possibility for retinal shape estimation. The current study compared retinal curvatures derived from OCT scans vs. PRX measurements in three refractive profiles (0° and 90° meridians, plus spherical equivalent) for 25 participants via Bland-Altman analysis. The radial differences between both procedures were correlated to axial length using Pearson correlation. In general, PRX- and OCT-based retinal radii showed low correlation (all intraclass correlation coefficients < 0.21). PRX found flatter retinal curvatures compared to OCT, with the highest absolute agreement found with the 90° meridian (mean difference +0.08 mm) and lowest in the 0° meridian (mean difference +0.89 mm). Moreover, a negative relation between axial length and the agreement of both methods was detected especially in the 90° meridian (R = -0.38, p = 0.06). PRX measurements tend to underestimate the retinal radius with increasing myopia when compared to OCT measurements. Therefore, future conclusions from PRX on retinal shape should be made cautiously. Rather, faster and more clinically feasible OCT imaging should be performed for this purpose.

To Correct or Not Correct? Actual Evidence, Controversy and the Questions That Remain Open.

Clinical studies and basic research have attempted to establish a relationship between myopia progression and single vision spectacle wear, albeit with unclear results. Single vision spectacle lenses are continuously used as the control group in myopia control trials. Hence, it is a matter of high relevance to investigate further whether they yield any shift on the refractive state, which could have been masked by being used as a control. In this review, eye development in relation to eyes fully corrected versus those under-corrected is discussed, and new guidelines are provided for the analysis of structural eye changes due to optical treatments. These guidelines are tested and optimised, while ethical implications are revisited. This newly described methodology can be translated to larger clinical trials, finally exerting the real effect of full correction via single vision spectacle lens wear on eye growth and myopia progression.