Myopic Children Research Articles

Systematic review and meta-analysis of the prevalence of myopia among school-age children in the Eastern Mediterranean Region.

The recent increase in myopia is a major public health concern worldwide, including in the Eastern Mediterranean Region (EMR). To provide data on the prevalence of myopia among school-age children in the EMR. This study was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol. We searched the Web of Sciences, Scopus, Index Medicus for the Eastern Mediterranean Region, ProQuest, PubMed, and Medline for studies on the prevalence of myopia in the EMR published from January 2000 to May 2022. The data were analysed using MedCalc version 19.6.1 and myopia was defined as refractive error ≥ 0.50 D. The overall pooled prevalence of myopia was estimated using a random-effects model and its associated 95% confidence intervals. The meta-analysis included 27 quality-assessed studies from 13 countries among 51 111 school-age children. The overall pooled prevalence of childhood myopia from 2000 to 2022 was 5.23%, which was significantly higher among females than males (4.90% vs 3.94%). The prevalence of myopia was significantly higher among children aged 11-17 years than among those aged 5-10 years (7.50% vs 3.90%). There was a higher prevalence of myopia with cycloplegic refraction than noncycloplegic refraction (5.95% vs 3.73%). There was highly significant heterogeneity between the studies. Prevalence of myopia among school-age children in the EMR was high, particularly among older children, and it was more common among females. Early intervention to slow myopia progression is essential in the EMR to protect children from irreversible vision loss.

Exploring the Relationship Between Maternal Nutrition During Pregnancy and Childhood Amblyopia and Myopia Risk: Longitudinal Cohort Studies

This study aimed to investigate the relationship between pregnancy and myopia onset or progression in young adult women, utilizing a longitudinal cohort design with a substantial sample size. Myopia is a prevalent refractive error with significant public health and economic implications. There are genetic and environmental risk factors for myopia; however, the role of pregnancy in the development of myopia is unknown. No longitudinal studies with extensive sample sizes have clarified the relationship between pregnancy and myopia. This study included 100 women aged 20–50 years, who were followed up biennially for up to 14 years. Pregnancy occurrences and myopia assessments were recorded. A comparison of individuals with and without pregnancies revealed differences in the incidence of myopia and amblyopia, their ages, and body mass index. Hazard ratios for myopia onset or progression were significantly lower in individuals with at least one pregnancy, particularly during the early follow-up periods. Sensitivity analyses and adjustments for confounders supported these findings. This study demonstrated that pregnancy may prevent myopia onset or progression, particularly during early adulthood. Future research should confirm these findings and investigate the underlying mechanisms, informing clinical decisions, including refractive surgery timing in women of childbearing age.

Efficacy of repeated low-level red-light therapy in the prevention and control of myopia in children

ObjectiveIn this study, we aimed to determine how different factors influence the effectiveness of repeated low-level red-light (RLRL) therapy in preventing and treating myopia in children. MethodsBetween June 2022 and April 2023, 336 children who visited our hospital due to myopia or significant decreases in hyperopia reserve were enrolled. The children were treated twice daily for three minutes with a head-mounted low-level red-light (single wavelength of 650 nm) therapeutic device. Each of the two treatment sessions was separated by at least four hours. The axial lengths and diopters of the children's eyes were compared before and three months after treatment, and the effects of gender, age, and baseline diopter on the efficacy of RLRL therapy were analyzed. ResultsFollowing three months of treatment, the average axial length of the eyes decreased by 0.031 mm. The condition was better for the boys than for girls, but the difference was not statistically significant. As age increased (F = 8.112, P = 0.000) or as the absolute value of baseline myopia degree increased (F = 10.51, P = 0.000), axial lengths of the eyes tended to decrease. The spherical equivalent refraction (SER) of children decreased by an average of 0.012 ± 0.355D. The condition was better for the boys than for girls, but the difference was not statistically significant. SER increased in the direction of hyperopic drift as age increased (F = 2.48, P = 0.031), or as the absolute value of baseline myopia degrees increased (F = 6.835, P = 0.000). There were no obvious side effects following the treatment. ConclusionThis study showed that RLRL therapy is a potential efficient, easily operable, and practically feasible method for the prevention and control of myopia.

Peripheral myopic defocus signal affects the efficiency of visual information processing in myopic children.

Spectacle lenses with peripheral lenslets have shown promise for myopia control by providing peripheral myopic defocus signals. Here, we aimed to investigate the impact of prolonged exposure (>6 months) to peripheral myopic defocus on visual information processing in myopic children. The study included 30 myopic children who habitually wore spectacle lenses with highly aspherical lenslets (HAL group) and 34 children who habitually wore single-vision (SV group) spectacles. The quick contrast sensitivity function (qCSF) was used to measure contrast sensitivity (CS) under conditions of no or high noise. Both groups were tested with HAL and SV lenses. The perceptual template model was utilised to fit the contrast sensitivity function (CSF) and determine differences in information processing efficiency through internal additive noise ( ) and perceptual template gain (β). The areas under the log CSF in the SV group were significantly higher than for the HAL group in both zero-noise conditions with the SV test lens (p = 0.03) and high-noise conditions with the HAL test lens (p = 0.02). For 2 cycle per degree (cpd) stimuli, β was significantly higher in the SV group with the HAL test lens than in the HAL group (p = 0.02), while there was a trend towards a significant difference in β for 6 cpd stimuli (p = 0.07). However, there were no significant differences in between the two groups, with or without noise interference. The reduced CS observed in myopic children wearing HAL lenses for 6 months or more may be due to decreased β. This suggests that prolonged use of spectacle lenses with peripheral myopic defocus signals may compromise the central visual system's ability to process additional external noise, resulting in decreased efficiency in visual information processing.

Evidence for the use of atropine to control myopia in children

To describe the effectiveness of using atropine as a method of controlling the progression of myopia in children. This is a systematic review study of literature, which search strategies in the Biblioteca Virtual em Saúde (BVS) and PubMed, through different combinations of the descriptors “Myopia”, “Control”, “Children” and “Atropine ” in the 2020-2023 timeframe. After selecting the inclusion and exclusion criteria, 30 articles compose the sample corpus. Atropine concentration is directly related to efficacy, with higher doses being more effective, however, also is associated with the appearance of adverse effects, especially photophobia. The most used dose is 0.01%, which presents positive results in control and fewer side effects; most of these studies involve the Asian population. There is a variation in results between populations, due to the different level of pigment in the iris, in addition to sociocultural differences between ethnicities. The lack of intervention can result in complications, with an increased risk related to the degree among children, and is not reduced with optical correction alone. The use of atropine is promising for controlling myopia in children, however it must be tested in association with other control methods and in different populations, so that the treatment is individualized and carried out in a way that presents results, in addition to reducing complications related to refractive disorder.

Optics of spectacle lenses intended to treat myopia progression.

This is a review of the optics of various spectacle lenses that have been used in myopia control over the last 60 years, with emphasis on approximately the last 15 years.Myopia has become an increasing health problem worldwide, particularly in some East Asian countries. This has led to many attempts to slow its progression in children and reduce its endpoint value. This review is concerned with the optics of spectacle lenses for use in myopia control, from bifocal lenses to multisegment and diffusion optics lenses. Treatments are based on theories of the onset or progression of myopia. These include the hypotheses that eye growth and myopia in susceptible children may be stimulated by (1) poor accommodation response and the consequent hyperopic defocus with near vision tasks, (2) relative hyperopic peripheral refraction, and (3) high retinal image contrast as occurs in urban environments. Using spectacle lenses to slow myopia progression has a history of about 60 years. The review is laid out in approximately the order in which different types of lenses have been introduced: bifocals, conventional progressive addition lenses, undercorrection with single-vision lenses, specialized progressive addition lenses, defocus-incorporated multiple segments, diffusion optics, and concentric bifocals. In the review, some of the lenses are combined with an eye model to determine refractive errors for peripheral vision for the stationary eye and for foveal vision for the rotating eye. Numbers are provided for the reported success of particular designs in retarding myopia progression, but this is not an epidemiological paper, and there is no critical review of the findings. Some of the recent treatments, such as multiple segments, appear to reduce the eye growth and myopia progression by better than 50% over periods of up to 2 years.

Myopic maculopathy among Chinese children with high myopia and its association with choroidal and retinal changes: the SCALE-HM study

AimsTo investigate myopic maculopathy in Chinese children with high myopia and its association with choroidal and retinal changes.MethodsThis cross-sectional study included Chinese children aged 4–18 years with high myopia. Myopic...

Verification of a nationwide population-based myopia growth chart in a large longitudinal cohort of 1155 Korean children.

To evaluate predictive value of the myopia growth chart based on population-based health survey data using longitudinal cohorts. Patients aged from 5 to 18years and underwent two or more cycloplegic refraction (CR) exams with at least one year of interval were included. Percentile deviation was calculated by subtracting percentile at final exam from the percentile at initial exam based on the chart. Spherical equivalent (SE) deviation was calculated by SE at final CR subtracted from predicted SE based on initial CR using the chart. 2310 eyes from 1155 subjects were included. There were 1344 eyes (58.2%) categorized as inliers, where both initial and final CR were within the 2nd to 99th percentile. Mean percentile and SE deviations were + 11.0 ± 22.9 percentiles and -0.60 ± 1.33 diopters, each. Outliers, those except the inliers, were 966 eyes (41.8%). Most outliers (709 eyes, 73.4%) were outside the chart for both initial and final exam. The rest of the outliers (257 eyes, 26.2%) were within the 2 to 99 percentile range on the chart at least once, either at initial or final exams; most of those (202 eyes, 78.6%) progressed toward myopia more than predicted. In our large cohorts, both inliers and outliers tended to progress toward more myopia than predicted from the chart. This suggests the chart predicts childhood myopia rather conservatively. The myopia growth chart may be useful as a screening tool in detecting children at high risk of developing high myopia.

Slowing myopia progression in children

Background: A large proportion of individuals develop myopia, which is recognized as a global health concern and is predicted to increase in prevalence. Long-term eye problems are associated with myopia, particularly in young individuals. Retinal detachment and choroidal degeneration are among the causes of visual impairments associated with myopia. In this narrative review, we summarized the current measures for slowing myopia progression in children, including their safety profiles and potential drawbacks. Methods: We conducted an English literature search for articles published between January 1, 2000, and October 31, 2023, using various combinations of keywords related to myopia, myopia progression, childhood myopia, myopia control, atropine, orthokeratology, and contact lenses. We included original or review articles pertaining to lifestyle changes and pharmacological, optical, or laser interventions for managing myopia progression in children. Our search was conducted using PubMed/MEDLINE, Google Scholar, and the Wiley Online Library. We reviewed the full text of included articles and qualitatively summarized the results of relevant studies using a narrative synthesis approach. Results: Multiple meta-analyses indicated that increased outdoor time is associated with a lower myopia prevalence, with each extra hour spent outside each week reducing the risk of myopia by 2%. Candidate drugs, such as atropine, pirenzepine, and 7-methylxanthine, and certain intraocular pressure-lowering medications, such as timolol, have been studied in human trials for their ability to manage myopia. The nonselective antimuscarinic drug atropine, followed by the M1-selective antimuscarinic drug pirenzepine, displayed positive results in slowing myopia. Oral 7-methylxanthine, a nonselective adenosine receptor antagonist, reduces axial myopia caused by hyperopic defocus in a primate model. Low-intensity laser therapy using low doses of red and near-infrared light, visual biofeedback training, bifocal or multifocal spectacles, orthokeratology using a rigid gas-permeable contact lens, combined orthokeratology and atropine, soft contact lenses with a central distance zone and higher positive power in the periphery, and peripheral defocus contact lenses are among the interventional therapies with promising results in managing myopia progression in children. Conclusions: The current literature supports the efficacy of increased outdoor time, administration of pharmacological agents, and special contact lenses as treatment modalities for slowing myopia progression in children. The effectiveness of orthokeratology alone and in combination with topical atropine therapy has also been assessed. Further research is needed to pinpoint the precise mechanisms of action of these therapies and to determine the best course of treatment. The increasing global prevalence of childhood myopia necessitates robust interventional studies into slowing myopia progression and preventing high myopia and related sight-threatening conditions in adulthood.

Myopia Management Need in Germany

Purpose: The increasing prevalence of myopia, particularly in Southeast Asia, and the predicted increase of the prevalence of myopia in Western countries mean that more children will benefit from myopia management. The current study evaluated by retrospectively analyzing electronic health records from eye health care practices in Germany how many children receiving single vision correction showed an annual myopia progression that indicates the need of myopia management (MM). Material and Methods: The Euronet database with a total data set of > 1 million orders from the years 2000 to 2020 served as the basis for the present analysis. The dataset was filtered by age (6 - 14 years), refractive errors and the presence of longitudinal order data (baseline and second visit after 11 - 24 months, n = 64,825). First, the database was filtered to only include children with a myopic refraction of the right eye (in terms of the SE) of −0.5 D or below (n = 52,936). Next, the database was divided into children with an annual progression of the SE of ≤ −0.5 D (as a criterion for the need of MM, n = 25,432) and children with an annual progression of > −0.50 D (n = 27,504), respectively. The number of children that require MM per shop per year was evaluated and the groups were further characterized with regards to the distribution of baseline SE and SE progression. Results: The analysis revealed that there are children of all ages who require myopia management, while their number increases with age, reaching a maximum at 10 to 11 years and declining afterwards (60 % of all children at age 7 and 30 % of all children at age 14, respectively). Children who have an early onset and high progression have baseline SE of around −1.50 D to −1.75 D and a second prescription SE of around −3.00 D. In contrast, children with later onset and lower progression have a similar baseline SE (average −1.62 D) but develop a second prescription SE of only around −2.00 D. Conclusion: Awareness of myopia, its progression and its potential impact on eye health needs to be raised in Germany. Even though the absolute number of children requiring myopia management is still rather low compared to other regions, the baseline refraction of myopic children is already very high. It is important to note that children who require myopia management benefit from efficient treatment options.

A retrospective study of cumulative absolute reduction in axial length after photobiomodulation therapy

BackgroundTo assess the age and timeline distribution of ocular axial length shortening among myopic children treated with photobiomodulation therapy in the real world situations.MethodsRetrospective study of photobiomodulation therapy in Chinese children aged 4 to 13 years old where axial length measurements were recorded and assessed to determine effectiveness at two age groups (4 ∼ 8 years old group and 9 ∼ 13 years old group). Data was collected from myopic children who received photobiomodulation therapy for 6 ∼ 12 months. Effectiveness of myopia control was defined as any follow-up axial length ≤ baseline axial length, confirming a reduction in axial length. Independent t-test was used to compare the effectiveness of the younger group and the older group with SPSS 22.0.Results342 myopic children were included with mean age 8.64 ± 2.20 years and baseline mean axial length of 24.41 ± 1.17 mm. There were 85.40%, 46.30%, 71.20% and 58.30% children with axial length shortening recorded at follow-up for 1 month, 3 months, 6 months and 12 months, respectively. With respect to the axial length shortened eyes, the mean axial length difference (standard deviation) was − 0.039 (0.11) mm, -0.032 (0.11) mm, -0.037 (0.12) mm, -0.028 (0.57) mm at 1, 3, 6, and 12-month follow-up, respectively. Greater AL shortening was observed among the older group who had longer baseline axial lengths than the younger group (P < 0.001).ConclusionsOverall myopia control effectiveness using photobiomodulation therapy was shown to be age and time related, with the maximum absolute reduction in axial elongation being cumulative.

Effect of spectacle lenses with aspherical lenslets on choroidal thickness in myopic children: a 3-year follow-up study

BackgroundTo investigate the impact of wearing spectacle lenses with highly aspherical lenslets (HAL) for 3 years and the impact of switching from single-vision lenses (SVL) to HAL on choroidal thickness (ChT).MethodsFifty-one participants who had already worn HAL for 2 years continued wearing them for an additional year (HAL group). Further, 50 and 41 participants who had worn spectacle lenses with slightly aspherical lenslets (SAL) and SVL for 2 years, respectively, switched to wearing HAL for another year (SAL-HAL and SVL-HAL groups). Additionally, 48 new participants aged 10–15 years were enrolled to wear SVL at the third year (new-SVL group). ChT was measured every 6 months throughout the study.ResultsSignificant differences were observed in the changes in ChT among the four groups at the third year (all P < 0.05 except for the outer nasal region: P = 0.09), with the new-SVL group showing larger reductions compared with the other three groups. However, none of the three HAL-wearing groups showed significant changes in ChT at the third year (all P > 0.05). When comparing the changes in ChT for 3 years among the HAL, SAL-HAL, and SVL-HAL groups, significant differences were found before switching to HAL, but these differences were abolished after all participants switched to HAL.ConclusionsCompared to those in the SVL group, choroid thinning was significantly inhibited in all the HAL groups. Wearing HAL for 3 years no longer had a choroidal thickening effect but could still inhibit choroidal thinning compared to wearing SVL.Trial registrationThe study was registered at the Chinese Clinical Trial Registry (ChiCTR1800017683), http://www.chictr.org.cn/showproj.aspx?proj=29789.

Effect of 0.01% atropine combined with orthokeratology lens on axial elongation: a 2-year randomized, double-masked, placebo-controlled, cross-over trial.

To evaluate the effect of 0.01% atropine combined with orthokeratology (OK) lens on axial elongation in schoolchildren with myopia. Sixty children aged 8-12 years with spherical equivalent refraction (SER) from -1.00D to -4.00D in both eyes were enrolled in this randomized, double-masked, placebo-controlled, cross-over trial. Children who had been wearing OK lenses for 2 months were randomly assigned into combination group (combination of OK lens and 0.01% atropine) for 1 year followed by control group (combination of OK lens and placebo) for another 1 year or vice versa. This trial was registered in the Chinese Clinical Trial Registry (Number: ChiCTR2000033904, 16/06/2020). The primary outcome was changes in axial length (AL). Data of right eyes were analyzed. There were statistically significant differences in the changes in AL between combination and control groups after generalized estimating equation model adjusting for age and baseline SER (p = 0.001). The mean axial elongation difference between combination and control groups was 0.10 mm in the first year (0.10 ± 0.13 mm vs. 0.20 ±0.15 mm; p = 0.01), and 0.09 mm in the second year (0.22 ± 0.10 mm vs. 0.13 ± 0.14 mm; p = 0.01), respectively. The mean axial elongation difference of two groups in the first year was similar to that in the second year during the cross-over treatment. In central Mainland China in myopic children, the treatment of combination therapy is more effective than single OK lens in controlling axial elongation.

Literature Review of the New Role of Atropine Eye Drop on Children's Myopia Progression

Myopia is one of the most common refractive disorders, especially in children. It can increase the risk of degenerative eye diseases. Various studies have been conducted to date to show the potential of variations of atropine in inhibiting the progression of myopia. This scientific article summarizes the various research, mainly related to the effectiveness of atropine on myopia. The research method uses "Literature Review" by searching Pubmed and Google Scholar with the English keywords ((“Myopia” OR “Refractive error”) AND “Children” AND “Atropine” AND “Progression”), 2018 until 2023. The discussion summarizes the role of atropine in myopia and its effectiveness and safety. Future research is expected to explore, more specifically, the role of atropine in inhibiting the progression of Myopia.

Effectiveness of repeated low-level red light in myopia prevention and myopia control

Background/aimsTo compare the effects of repeated low-level red light (RLRL) treatment on axial length growth and refractive error changes in myopic and premyopic children.MethodsSubjects were assigned randomly to four subgroups:...

An Insight into Knowledge, Perspective, and Practices of Indian Optometrists towards Childhood Myopia.

The current understanding of clinical approaches and barriers in managing childhood myopia among Indian optometrists is limited. This research underscores the necessity and relevance of evidence-based practice guidelines by exploring their knowledge, attitude, and practice towards childhood myopia. A self-administered internet-based 26-item survey was circulated online among practicing optometrists in India. The questions assessed the demographics, knowledge, self-reported clinical practice behavior, barriers, source of information guiding their management, and extent of adult caregiver engagement for childhood myopia. Of 393 responses, a significant proportion of respondents (32.6-92.4%) were unaware of the ocular complications associated with high myopia, with less than half (46.5%) routinely performing ocular biometry in clinical practice. Despite the growing awareness of emerging myopia management options, the uptake remains generally poor, with single-vision distance full-correction spectacles (70.3%) being the most common mode of vision correction. Barriers to adopting optimal myopia care are medicolegal concerns, absence of clinical practice guidelines, and inadequate consultation time. Own clinical experience and original research articles were the primary sources of information supporting clinical practice. Most (>70%) respondents considered involving the adult caregiver in their child's clinical decision-making process. While practitioners' awareness and activity of newer myopia management strategies are improving, there is plenty of scope for its enhancement. The importance of evidence-based practice guidelines and continuing education on myopia control might help practitioners enhance their clinical decision-making skills.

The relationship between accommodative and binocular function with myopia progression in myopic children undergoing orthokeratology

PurposeTo determine the relationship between changes in accommodative and binocular function with myopia progression in myopic children over a two-year follow-up period, and to determine when changes in visual functions stabilized after switching from spectacles to orthokeratology (Ortho-K). MethodsThis prospective, self-controlled study followed thirty-six participants (aged 8–14 years) for two years after they switched from spectacles to Ortho-K. Accommodative and binocular function were assessed prior to and 1, 3, 6, 12, 18 and 24 months after commencing Ortho-K. Measurements included accommodative amplitude, accommodative response, accommodative facility, accommodative convergence/accommodation (AC/A), ocular alignment, positive relative accommodation (PRA), negative relative accommodation (NRA), horizontal vergence range, reading ability and stereoacuity. Myopia progression was quantified by the change in axial length. ResultsOcular alignment, monocular and binocular accommodative facility, and PRA stabilized after 1 month. The distance blur point in the convergence range, the distance break and recovery point in the divergence range, accommodative amplitude, calculated AC/A, stereoacuity and reading ability stabilized within 6 months. After two years of Ortho-K, NRA significantly increased (p = 0.044), while it showed no significant difference after one-year of lens wear (p = 0.49). The distance break point in the convergence range showed no significant difference (p = 0.20), but significantly decreased after one-year (p = 0.005). There were no significant correlations between the change in axial length with changes in accommodative or binocular function (p > 0.05). ConclusionAccommodative and binocular function changed significantly after switching from spectacles to Ortho-K and most of the parameters stabilized within the first 6 months. There was no association between the change in accommodative or binocular function and myopia progression.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia.

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye. The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length. This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly. The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

Vision-related quality of life in children: Cross-cultural adaptation and test-retest reliability of the Danish version of the paediatric refractive error profile 2.

To translate and cross-culturally adapt PREP2 into Danish and to investigate the face validity and reliability of Danish PREP2 through cognitive interviewing, Rasch and reliability analyses. The Danish PREP2 was translated using a standardized procedure and then pretested following the Three-Steps-Interviews (TSTI) process. A total of 15 myopic children aged 7-14 wearing either orthokeratology lenses (ortho-k) or single-vision spectacles (SVS) were included in pretesting comprising cognitive interviews and Rasch analysis. Data from cognitive interviewing was analysed thematically according to Collins. Rasch analysis was used to pretest the psychometric properties in terms of person- and item-fit statistics. Reliability was assessed via test-retest using Intra-class correlation coefficient (ICC) in the CONTROL study population, which consisted of 60 Danish children aged 7-14 years wearing either ortho-k or SVS. Fifteen children participated in pilot studies comprising of cognitive interviewing and Rasch analysis and 44 out of 60 CONTROL children participated in test-retest reliability analysis. The translation process resulted in a Danish version of PREP2 corroborating the original. Pretesting highlighted issues in the contextualization of items and in marking responses. Thus, we introduced a digital format with help texts. Cognitive interviewing identified issues in the following Collins' themes: comprehension (understanding of concepts), judgement (ambiguity of items) and response (selecting answers). Rasch analysis indicated that help texts were useful for clarifying context. The ICC was 0.77 (95% CI: 0.66-0.85). The cross-cultural adaptation of PREP2 was satisfactory and issues were identified and corrected through pretesting. The test-retest reliability showed substantial consistency. The instrument could be validated in a more generalizable setting in future studies. NCT03246464 (CONTROL study).

Study of association between corneal shape parameters and axial length elongation during orthokeratology using image-pro plus software

BackgroundThe aim was to validate the correlation between corneal shape parameters and axial length growth (ALG) during orthokeratology using Image-Pro Plus (IPP) 6.0 software.MethodsThis retrospective study used medical records of myopic children aged 8–13 years (n = 104) undergoing orthokeratology. Their corneal topography and axial length were measured at baseline and subsequent follow-ups after lens wear. Corneal shape parameters, including the treatment zone (TZ) area, TZ diameter, TZ fractal dimension, TZ radius ratio, eccentric distance, pupil area, and pupillary peripheral steepened zone(PSZ) area, were measured using IPP software. The impact of corneal shape parameters at 3 months post-orthokeratology visit on 1.5-year ALG was evaluated using multivariate linear regression analysis.ResultsALG exhibited significant associations with age, TZ area, TZ diameter, TZ fractal dimension, and eccentric distance on univariate linear regression analysis. Multivariate regression analysis identified age, TZ area, and eccentric distance as significantly correlated with ALG (all P < 0.01), with eccentric distance showing the strongest correlation (β = −0.370). The regressive equation was y = 1.870 − 0.235a + 0.276b − 0.370c, where y represents ALG, a represents age, b represents TZ area, and c represents eccentric distance; R2 = 0.27). No significant relationships were observed between the TZ radius ratio, pupillary PSZ area, and ALG.ConclusionsIPP software proves effective in capturing precise corneal shape parameters after orthokeratology. Eccentric distance, rather than age or the TZ area, significantly influences ALG retardation.