Myopia Control Effect Research Articles

Comparison of different concentrations atropine in controlling children and adolescent myopia: an umbrella review of systematic reviews and meta-analyses.

To evaluate the myopia control effect of different concentrations atropine in children and adolescent. Meta-analyses and systematic reviews available in the Pubmed, Embase, and Cochrane Library databases from the databases' inception to August 2023 were searched to evaluate the efficacy and tolerability of different concentrations' atropine in controlling myopia progression. Overall effects were performed using random-effects model. AMSTAR 2 tool was used to assess the quality of included studies. Prespecified outcomes were weight mean difference (WMD) with 95% credible interval (95% CI) of annual spherical equivalent refraction (SER) changes and annual axial length (AL) changes. 19 systematic reviews/meta-analyses of different atropine concentrations were included in the analysis. 14 studies reported SER changes, and 17 reported AL changes. In terms of the studies' overall methodological quality level (measured using AMSTAR 2), 1 study was rated high, 7 moderate, 7 low, and 4 critically low. The 0.01% atropine was found to have statistically significance (annual SER change WMD 0.27 [95% CI 0.21 - 0.34] D/year; annual AL change WMD -0.09 [95% CI -0.1 to -0.07]) mm/year), 0.05% atropine was preferred considering efficacy and tolerability (annual SER change WMD 0.54 [95% CI 0.49 - 0.58] D/year; annual AL change WMD -0.21 [95% CI -0.12 to -0.02]) mm/year). Different atropine concentrations alleviated children and adolescent myopia progression. However, higher-quality evidence and further investigation are needed to clarify the dose-response relationship, and practical guidelines must be developed to determine myopia control efficacy.

Efficacy of Combining Highly Aspherical Lenslets Spectacles With 0.01% Atropine Eye Drops in Myopia Control

To explore the difference in myopia control efficacy between spectacle lenses with highly aspherical lenslets (HAL) combined with 0.01% atropine eye drops and spectacle lenses with HAL alone or single vision spectacle lenses (SVL) in children and adolescents. A retrospective cohort study was conducted with a total of 105 myopic children aged 6-15 years. According to the specific myopia correction and control methods of each subject, they were evenly divided into the HAL+0.01% atropine (HAL+AT) group, the HAL group, and the SVL group, with 35 subjects in each group. Relevant data, such as cycloplegic refraction and axial length (AL) at baseline and 12 months after wearing spectacles, were retrieved. One-way analysis of variance, or the Kruskal-Wallis test, was used to analyze the changes in AL and spherical equivalent refraction (SER) after wearing spectacles for 12 months in comparison to those at baseline in the three groups. There was no statistically significant difference in the baseline parameters and duration of wearing spectacles among the three groups (P>0.05). After wearing spectacles for 12 months, the changes in SER were －0.13 (－0.25, 0.00) D, －0.25 (－0.63, －0.25) D, and －0.63 (－1.00, －0.25) D in the HAL+AT group, HAL group, and SVL group, respectively; AL elongation in the three groups was (0.09±0.11) mm, (0.19±0.16) mm, and (0.34±0.16) mm, respectively. The HAL+AT group exhibited slower SER changes (P HAL+AT vs. HAL=0.001, P HAL+AT vs. SVL=0.002) and AL elongation (P HAL+AT vs. HAL=0.009, P HAL+AT vs. SVL=0.001) than those of the HAL and the SVL groups. Compared with those of the SVL group, myopia progression was reduced by 79.4% and AL elongation was slowed down by 73.5% in the HAL+AT group, while in the HAL group, myopia progression and AL elongation were reduced by 60.3% and 44.1%, respectively. According to stratified analysis based on age and myopia progression rate, among younger children aged 6 to 8 years and older children aged 9 to 15 years, the HAL+AT group had a significantly lower proportion of subjects experiencing fast AL elongation (AL>0.36 mm/year) and a significantly higher proportion of subjects experiencing slow AL elongation (AL≤0.18 mm/year) compared to the SVL group (P<0.017). The combination intervention of spectacle lenses with HAL and 0.01% atropine eye drops is effective in controlling myopia progression in children and adolescents, with better myopia control effect achieved using this combination intervention in myopic children of all ages.

Myopia Control Effect of Defocus Incorporated Multiple Segments (DIMS) Spectacle Lens in Pakistani Children

Background: Myopia is a growing concern globally, particularly among school-aged children, leading to severe ocular complications if untreated. Objective: The purpose of this research was to determine the effectiveness of DIMS spectacle lenses in preventing myopia progression in Pakistani children. Methods: The current study was tested clinically for two years with two hundred myopic youngsters aged six to twelve years. The subjects were divided into two groups; the first group received DIMS lenses while the second group received single vision lenses. Biometry of the axial length was done using the IOL Master 500 (Carl Zeiss Meditec) and the cycloplegic autorefraction was done using the Topcon KR-800S. For monitoring the progression of myopia, axial length measurements and cycloplegic autorefraction were performed with an interval of six months. Quantitative data were analysed using independent t-tests and mixed-effects models in order to compare the results between the groups. Results: Comparing the DIMS group to the single vision lens group, the children in the former demonstrated slower myopia development. Whereas the control group's mean myopic shift was -0.67 ± 0.30 D/year, the DIMS groups was -0.32 ± 0.25 D/year (p &lt; 0.001). Significantly less axial length changes (0.15 ± 0.10 mm/year) were seen in the DIMS group as compared to the control group (0.31 ± 0.12 mm/year) (p &lt; 0.001). Conclusion: DIMS spectacle lenses are effective in preventing the progression of myopia in Pakistani children. Their use could be a viable approach to managing myopia in this population. However, the study is limited by its short follow-up period and the lack of data on long-term outcomes.

The efficacy of orthokeratology lenses with smaller back optic zone diameter in myopia control. A meta-analysis.

This study was conducted to determine whether orthokeratology (OK) lenses with a smaller back optic zone diameter (BOZD) could exhibit stronger myopia control effects. A meta-analysis was registered in PROSPERO (CRD42023408184). A comprehensive systematic database search was conducted, encompassing PubMed, Cochrane Library, EMBASE, MEDLINE, Web of Science, Ovid, CNKI and CBM, to identify relevant studies up to 25 March 2023. The primary inclusion criteria for this meta-analysis were studies that investigated the myopia control effect of OK lenses with a small optical treatment area (≤5 mm). To assess the quality of the retrieved articles, two researchers evaluated them using the Cochrane bias risk assessment criteria. The primary outcome measures were the changes in axial length (AL) and refractive error, using the weighted mean differences (WMD) and 95% confidence intervals (CI) to assess differences between small and traditional back optical treatment zone groups in terms of these outcomes. The analysis encompassed five eligible studies, with a 1 year duration. The average difference in AL between the groups was 0.12 mm (WMD = -0.12, 95% CI [-0.16, -0.09], p < 0.00001). Likewise, the average difference in refractive error between the two groups was 0.44 D (WMD = 0.44, 95% CI [0.30, 0.57], p < 0.00001). None of the studies reported severe adverse events. Current evidence suggests that OK lenses with smaller back optical treatment zone are more effective in preventing myopia progression than traditional lenses. However, a longer-term evaluation is warranted.

Myopia Control Effect of Repeated Low-Level Red-Light Therapy Combined with Orthokeratology: A Multicenter Randomized Controlled Trial

To investigate the efficacy and safety of repeated low-level red-light(RLRL) therapy combined with orthokeratology(Ortho-k) among the children who, despite undergoing Ortho-k treatment, exhibited an axial elongation of at least 0.50mm over 1 year. Multicenter, randomized, parallel-group, single-blind clinical trial (ClinicaTrials.gov,NCT04722874). Eligible children were aged 8-13 years with a cycloplegic spherical equivalent refraction of -1.00 to -5.00 diopters in the initial Ortho-k fitting examination and had annual axial length (AL) elongation ≥ 0.50 mm despite undergoing Ortho-k for 1 year. A total of 48 children were enrolled from March 2021 to January 2022, and the final follow-up was completed in March 2023. Children were randomly assigned to the RLRL combined with Ortho-k(RCO) or the Ortho-k group in a 2:1 ratio. The Ortho-k group wore Ortho-k at least 8 hours per night, while the RCO group received daily RLRL therapy twice a day for 3 minutes in addition to Ortho-k wearing. The primary outcome was AL change measured at 12 months relative to baseline. The primary analysis was conducted in children who received the assigned intervention and completed at least 1 post-randomization follow-up using the modified intention-to-treat principle. A total of 47(97.9%) children were included in the analysis (30 in the RCO group and 17 in the Ortho-k group). The mean axial elongation rate before the trial was 0.60mm/year in the RCO group and 0.61mm/year in the Ortho-k group. After 12 months following the intended intervention, the adjusted mean AL changes were -0.02mm(95% CI, -0.08 to +0.03 mm) in the RCO group and 0.27mm(0.19-0.34 mm) in the Ortho-k group. The adjusted mean difference in AL change was -0.29mm(-0.44 to -0.14mm) between the RCO and Ortho-k groups. The percentage of children achieving an uncorrected visual acuity greater than 20/25 was similar in the RCO (64.3%) and Ortho-k (65.5%) groups (Chi2 test, P=0.937). Combining RLRL therapy with Ortho-k may offer a promising approach to optimize axial elongation control among myopic children. This approach also potentially allows children to achieve satisfactory visual acuity, reducing the daytime dependence on corrective eyewear.

Effect of Low-dose Atropine on Myopia Control in Children Operated for Intermittent Exotropia

Purpose: To evaluate the effect of low-dose atropine on myopia control in children with a history of surgery for intermittent exotropia (IXT).Methods: We retrospectively reviewed the medical records of children who used 0.05% atropine for ≥ 1 year to control myopia progression. This group included 45 patients with a history of IXT surgery and 57 patients with no such history. The annual changes in spherical equivalent and axial length were compared 6 months before, 6 months after, and 1 year after atropine instillation between the IXT surgery group and myopia controls. In this comparison, the dominant eye was paired with the right eye and the non-dominant eye with the left eye. We also analyzed the difference between IXT surgery cases corrected within versus not within 10 prism diopters (PD) at the start of low-dose atropine treatment.Results: A total of 102 patients had an average of -3.81 ± 1.53 diopters (D) and used low-dose atropine for an average of 16.8 months from a mean age of 8.2 years. On average, the IXT surgery group underwent muscle surgery for 28.1 PD of IXT at 7.8 years. A year after instillation, the myopia progression rate was -0.52 ± 0.89 D/year and 0.27 ± 0.40 mm/year in the IXT surgery group compared to -0.47 ± 0.83 D/year and 0.31 ± 0.24 mm/year in the myopia control group with no significant differences. However, after 6 months of instillation, the dominant eye in the IXT surgery group exhibited a significantly faster myopia progression rate than the right eye in the myopia control group (-0.84 ± 1.61 D/year vs. -0.56 ± 0.80 D/year, &lt;i&gt;p&lt;/i&gt; = 0.04; 0.27 ± 0.33 mm/year vs. 0.22 ± 0.21 mm/year, &lt;i&gt;p&lt;/i&gt; = 0.02). No difference was found in the myopia control effect between corrected and uncorrected cases in the IXT surgery group.Conclusions: The effect of low-dose atropine on myopia control in children after IXT surgery was similar to that in myopia controls. However, it was less effective in the dominant eye during the early treatment period.

Light exposure therapy for myopia control: a systematic review and Bayesian network meta-analysis

AimsTo compare and rank the myopia control effects of different light wavelengths in children using a systematic review and Bayesian network meta-analysis (Bayesian NMA).MethodsThe review protocol was registered with PROSPERO....

Deep Learning Based Prediction of Myopia Control Effect in Children Treated With Overnight Orthokeratology.

To develop and validate a deep learning-based model for predicting 12-month axial length (AL) elongation using baseline factors and early corneal topographic changes in children treated with orthokeratology (Ortho-K) and to investigate the association between these factors and myopia control impact. A total of 115 patients with Ortho-K were enrolled. Influential baseline factors that have a statistically significant correlation with 12-month AL from medical records were selected using Pearson correlation coefficients. Simultaneously, the height, area, and volume of the defocus region were directly calculated from the corneal topography. Then, the prediction model was developed by combining multiple linear regression and deep neural network and evaluated in an independent group (83 patients for developing the algorithm and 32 patients for evaluation). Age ( r= -0.30, P <0.001), spherical equivalent refractive (SE; r =0.20, P =0.032), and sex ( r =0.19, P =0.032) were significantly correlated with the AL elongation while pupil diameter, flat k, steep k, horizontal corneal diameter (white to white), anterior chamber depth, and cell density were not ( P >0.1). The prediction model was developed using age, SE, and corneal topographic variation, and the validation of the model demonstrated its effectiveness in predicting AL elongation. The AL elongation was accurately predicted by the deep learning model, which effectively incorporated both baseline factors and corneal topographic variation.

Ocular Posterior Segment Distribution and Pharmacokinetics of Brimonidine After Intravitreal Administration in Guinea Pigs.

Purpose: Brimonidine is a highly alpha-2 adrenergic agonist, which provides a potential myopia control effect. This study aimed to examine the pharmacokinetics and concentration of brimonidine in the posterior segment tissue of eyes in guinea pigs. Methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was successfully used for brimonidine pharmacokinetics and tissue distribution research in guinea pigs following intravitreal administration (20 μg/eye). Results: Brimonidine concentrations in the retina and sclera were maintained at a high level (>60 ng/g) at 96 h postdosing. Brimonidine concentration peaked in the retina (377.86 ng/g) at 2.41 h and sclera (306.18 ng/g) at 6.98 h. The area under curve (AUC0-∞) was 27,179.99 ng h/g in the retina and 39,529.03 ng h/g in the sclera. The elimination half-life (T1/2e) was 62.43 h in the retina and 67.94 h in the sclera. Conclusions: The results indicated that brimonidine was rapidly absorbed and diffused to the retina and sclera. Meanwhile, it maintained higher posterior tissue concentrations, which can effectively activate the alpha-2 adrenergic receptor. This may provide pharmacokinetic evidence for the inhibition of myopia progression by brimonidine in animal experiments.

Paying attention to the prevention and control methods of myopia and associated visual quality in adolescents

Myopia prevention and control has become one of the difficulties of eye health in China. Previous studies have focused on the effect of myopia control, but less on the visual performance and visual quality caused by various approaches to myopia control for adolescents. On one hand, most of the prevention methods can achieve myopia control by affecting retinal imaging. On the other hand, they can affect the visual quality and even the quality of daily life. Therefore, a balance between myopia control effects and visual quality needs to be considered in clinical work. This article points out the importance of improving visual quality in the process of myopia prevention and control, analyzes the problems of visual quality related to the myopia prevention and control methods, and puts forward suggestions on myopia management, so as to improve the visual quality with the effective prevention and control of myopia in adolescents.Finally, improving the comprehensive prevention and control level of myopia for adolescents.Finally, improving the comprehensive prevention and control level of myopia for adolescents.

Long-term myopia control effect and safety in children wearing DIMS spectacle lenses for 6 years

This study evaluated the long-term myopia control effect and safety in children wearing Defocus Incorporated Multiple Segments (DIMS) spectacle lenses. Participants who completed the 2-year RCT were followed for a total of 6 years; their cycloplegic refractions and axial length were measured. Group 1 (n = 36) wore DIMS spectacles for 6 years; Group 2 (n = 14) wore DIMS lens for the first 3.5 years and SV spectacles afterwards; Group 3 (n = 22) wore SV spectacles in the first 2 years and switched to DIMS; Group 4 (n = 18) wore SV spectacles in the first 2 years, switched to DIMS for 1.5 years and then SV spectacles again. Group 1 showed no significant differences in myopia progression (− 0.52 ± 0.66 vs. − 0.40 ± 0.72D) and axial elongation (0.32 ± 0.26 vs. 0.28 ± 0.28 mm, both p > 0.05) between the first and the later 3 years. In the last 2.5 years, DIMS lens groups (Groups 1 and 3) had less myopia progression and axial elongation than the single vision groups (Groups 2 and 4). There was no evidence of rebound after stopping the treatment. Post-wear visual functions in all groups were within norms. The results supported that DIMS lenses provided sustained myopia control without adverse effects over the 6-year study period.Trial registration: clinicaltrials.gov; NCT02206217.

Long-term follow-up of changes in ocular biometric parameters in orthokeratology lens wearers with relatively large-scale axial length reduction

BackgroundTo investigate ocular biological characteristics for myopic children with axial length (AL) reduction during orthokeratology (Ortho-K) treatment and provide clinical clues for better myopia control effects.MethodsChanges in ocular parameters and treatment zone (TZ) in 75 subjects who completed one-year Ortho-K treatment were retrospectively reviewed. The subjects were divided into two groups according to one-year AL change: the AL reduction group (n = 37) and the AL elongation group (n = 38). Univariate and multivariate regression analyses were performed to determine the association between TZ, ocular parameters, and AL change.ResultsThere was no significant difference in baseline between the two groups (all P > 0.05). After one year of Ortho-K treatment, compared with those in the AL elongation group, children in the AL reduction group had a decreased anterior chamber depth (ACD) (P < 0.001), thickened crystalline lens thickness (CLT) (P = 0.002), thinned vitreous chamber depth (VCD) (P < 0.001) and smaller TZ (P = 0.03), but no difference in central corneal thickness (CCT) and pupil diameter (PD). In the multivariable analyses, AL reduction was negatively associated with baseline age (beta: − 0.048; 95% CI: − 0.083 to − 0.013; P = 0.009) and positively associated with the TZ (beta: 0.024; 95% CI: 0.009 to 0.040; P = 0.003).ConclusionsIn AL reduction eyes, thickened CLT, decreased ACD and thinned VCD were observed during Ortho-K treatment, which could be suggested as indicators for better myopia control effects in the clinic. Older baseline age and smaller TZ wearing Ortho-K were also associated with AL change. Thickened CLT may be a result of compensation for AL-reduction eyes.

Efficacy in Myopia Control: Does Race Matter?

Efficacy in Myopia Control: Does Race Matter?

The effect of back optic zone diameter on relative corneal refractive power distribution and corneal higher-order aberrations in orthokeratology

PurposeTo compare axial elongation, relative corneal refractive power (RCRP) distribution within the pupillary diameter, and corneal higher-order aberrations (HOAs) in myopic children wearing orthokeratology (ortho-k) lenses with different back optic zone diameters (BOZD). MethodsChildren aged 8–11 years were fitted with 5.0 or 6.2 mm-BOZD ortho-k lenses (groups A and B, respectively). Axial length (AL) and corneal topography were measured at baseline and during the annual visit. RCRP and corneal HOAs were compared between the two groups after one-year treatment. Multivariate linear regression analysis was performed to determine the association between AL elongation and RCRP parameters, corneal HOAs, and other variables between the groups. ResultsAfter one-year treatment, axial elongation was slower in group A than in group B, with a difference of 0.15 mm. Children in group A showed smaller treatment zone size, smaller 3/4X value (describing the distance from the apex RCRP profile rising to its three-quarter-peak level), greater RCRP sum value within the pupillary area, and higher increases in corneal total HOAs and horizontal coma (Z31). AL elongation was significantly correlated with baseline age, baseline spherical equivalent refraction (SER), treatment zone size, and 3/4X value. ConclusionsOrtho-k lenses designed with smaller BOZD increased myopia control efficacy, induced a steeper distribution of the RCRP profile within the pupillary diameter, and induced greater increases in corneal total HOAs and horizontal coma (Z31). Lens-induced RCRP profile within pupillary diameter, rising to its three-quarter-peak level at a smaller distance, may show a better myopia control effect.

Myopia Control Effect of Repeated Low-Level Red-Light Therapy in Chinese Children: A Randomized, Double-Blind, Controlled Clinical Trial

Repeated low-level red-light (RLRL) therapy is an emerging treatment for myopia control. Nevertheless, previous studies are limited by open-label design. Our study aimed to assess the efficacy and safety of RLRL therapy in controlling myopia progression compared to a sham device with only 10% of the original power. Randomized, double-blind, controlled clinical trial. A total of 112 Chinese children aged 7 to 12 years with myopia of at least -0.50 diopter (D), astigmatism of 1.50 D or less, and anisometropia of 1.50 D or less. Participants were assigned randomly in a 1:1 ratio to the RLRL group or the sham device control group, following a schedule of 3 minutes per session, twice daily, with an interval between sessions of at least 4 hours. The RLRL therapy was provided by a desktop red-light therapy device and administered at home. The sham device was the same device but with only 10% of the original device's power. Cycloplegic refraction and axial length (AL) were measured at baseline and 6 months. Changes in cycloplegic spherical equivalence refraction (SER) and AL between 2 groups were compared using a generalized estimating equation (GEE). A total of 111 children were included in the analysis (n= 56 in the RLRL group and n= 55 in the sham device control group). The mean SER change over 6 months was 0.06 ± 0.30 D in the RLRL group and -0.11 ± 0.33 D in the sham device control group (P= 0.003), with respective mean increases in AL of 0.02 ± 0.11 mm and 0.13 ± 0.10 mm (P < 0.001). In the multivariate GEE models, children in the RLRL group showed less myopia progression and axial elongation than those in the sham device control group (SER: coefficient, 0.167 D; 95% confidence interval [CI], 0.050-0.283 D; P= 0.005; AL: coefficient, -0.101 mm; 95% CI, -0.139 to -0.062 mm; P < 0.001). No treatment-related adverse events were reported. In myopic children, RLRL therapy with 100% power significantly reduced myopia progression over 6 months compared with those treated with a sham device of 10% original power. The RLRL treatment was well tolerated without treatment-related adverse effects.

Factors determining the myopia control effect of an orthokeratology lens: A two-year multi-level model.

A multi-level model was used to analyse factors, including environmental factors, affecting the controlling effect of orthokeratology on myopia progression. A 2-year prospective study was conducted in the West China Hospital, Sichuan University. Age, sex, height, baseline spherical equivalent refraction, choroidal thickness, axial length and other biometric ocular parameters were collected. Additionally, data on the following environmental factors were obtained: near-work distance and time, sleep time and time spent outdoors. After the baseline measurements, participants were followed up every 3months for 2years of lens wear. The primary outcome measure was axial length elongation over 2years of orthokeratology. All variables were included in a univariate, three-level analysis model with inclusion in the final multivariate multi-level model if statistically significant. Thirty-three participants (average age 9.73±1.55years) were included in this study. During the 2-year period of lens wearing, binocular changes in axial length increased significantly from the ninth month and continued until the end of the follow-up. Changes in axial length after 2years of lens wearing were 0.44±0.30mm and 0.37±0.26mm in the right and left eyes, respectively (both p<0.001). Based on the 2-year multi-level model, age, sex, baseline spherical equivalent refraction, flatter keratometry meridian and near-work time influence the effect of orthokeratology. This is the first study to use a multi-level model to analyse factors, including environmental factors, that affect myopia control using orthokeratology. These results showed that younger age, being female, having lower myopia at baseline, a steeper flattest keratometry meridian and no more than 5h of near work per day were associated with better myopia control effect using orthokeratology over a 2-year treatment period.

Myopia Control Effect Is Influenced by Baseline Relative Peripheral Refraction in Children Wearing Defocus Incorporated Multiple Segments (DIMS) Spectacle Lenses.

The aim of this study is to investigate if baseline relative peripheral refraction (RPR) influences the myopia control effects in Chinese myopic children wearing Defocus Incorporated Multiple Segments (DIMS) lenses. Peripheral refraction at 10°, 20°, and 30° nasal (10 N, 20 N, 30 N) and temporal (10 T, 20 T, 30 T) retina were measured at six-month intervals for children who participated in a 2-year randomized controlled trial. The relationship between the baseline peripheral refractions and myopia progression and axial length changes were analysed. A total of 79 children and 81 children in the DIMS and single vision (SV) group were investigated, respectively. In the DIMS group, more baseline myopic RPR spherical equivalent (SE) was associated with more myopic progression (10 N: r = 0.36, p = 0.001; 20 N: r = 0.35, p = 0.001) and greater axial elongation (10 N: r = −0.34, p = 0.001; 20 N: r = −0.29, p = 0.006) after adjusting for co-factors. In the SV group, baseline RPR had association with only myopia progression (10 N: r = 0.37, p = 0.001; 20 N: r = 0.36, p = 0.001; 30 N: r = 0.35, p = 0.002) but not with axial elongation after Bonferroni correction (p > 0.008). No statistically significant relationship was found between temporal retina and myopia progression or axial elongation in both groups. Children with baseline myopic RPR had statistically significant more myopia progression (mean difference around −0.40 D) and more axial elongation (mean difference 0.15 mm) when compared with the children having baseline hyperopic RPR in the DIMS group but not in the SV group. In conclusion, the baseline RPR profile may not influence future myopia progression or axial elongation for the SV lens wearers. However, DIMS lenses slowed down myopia progression and was better in myopia control for the children with baseline hyperopic RPR than the children with myopic RPR. This may partially explain why myopia control effects vary among myopic children. Customised myopic defocus for individuals may optimise myopia control effects, and further research to determine the optimal dosage, with consideration of peripheral retinal profile, is warranted.

Manual and software-based measurements of treatment zone parameters and characteristics in children with slow and fast axial elongation in orthokeratology.

To compare the treatment zone (TZ) measurements obtained using manual and software-based methods in orthokeratology (ortho-k) subjects and explore the TZ characteristics of children with slow and fast axial elongation after ortho-k. Data from 69 subjects (aged 7 to <13years old), who participated in three 24-month longitudinal orthokeratology studies, showing fast (>0.27mm, n=38) and slow (<0.09mm, n=31) axial elongation, were retrieved. The TZ after ortho-k was defined as the central flattened area enclosed by points with no refractive power change. TZ parameters, including decentration, size, width of the peripheral steepened zone (PSZ), central and peripheral refractive power changes and peripheral rate of power change, were determined manually and using python-based software. TZ parameters were compared between measurement methods and between groups. Almost all TZ parameters measured manually and with the aid of software were significantly different (p<0.05). Differences in decentration, size and the PSZ width were not clinically significant, but differences (0.45 to 0.92 D) in refractive power change in the PSZ were significant, although intraclass coefficients (0.95 to 0.98) indicated excellent agreement between methods. Significantly greater TZ decentration, smaller TZ size and greater inferior rate of power change (relative to the TZ centre) were observed in slow progressors using both methods, suggesting a potential role of TZ in regulating myopia progression in ortho-k. TZ measurements using manual and software-based methods differed significantly and cannot be used interchangeably. The combination of TZ decentration, TZ size and peripheral rate of power change may affect myopia control effect in ortho-k.

Change in Corneal Power Distribution in Orthokeratology: A Predictor for the Change in Axial Length.

PurposeTo investigate the correlation between the change in spatial corneal power distribution and axial length (AL) elongation during orthokeratology (Ortho-k) treatment using mathematical methods.MethodsSeventy-six subjects aged from eight to 13 years were fitted with Paragon CRT ortho-k lenses. Manifest refraction and corneal topography were checked at baseline and one day, one week, two weeks, one month, three months, six months, nine months, and one year after lens wear. AL was measured at baseline and the six-month and one-year follow-up visits. Relative corneal refractive power change (RCRPC) was calculated by a polynomial function and a monomial function. Factors including age, baseline spherical equivalent refractive error (SER), power exponent and RCRPC were tested against one-year AL growth in a stepwise multiple linear regression model.ResultsA total of 67 subjects completed the one-year study, with nine dropouts. The SER significantly reduced after the first month of lens wear (P < 0.001). AL significantly changed over time (P = 0.0003) with the annual growth being 0.32 ± 0.18 mm. Power exponent and RCRPC were stable throughout the follow-up visits (all P > 0.05). Change of AL was significantly correlated with baseline age (standardized β = −0.292, P < 0.001) and power exponent (standardized β = 0.691, P < 0.001), but not with the other factors being analyzed. The regression equation using baseline age (X1) and power exponent (X2) as functions for 1-year AL change (Y) was Y = 0.438-0.034X1 + 0.309X2, with R2 being 0.752.ConclusionsThe asphericity of the treatment zone may affect axial elongation in children undergoing ortho-k therapy.Translational RelevanceBecause the ortho-k lens design may affect myopia control effect in children undergoing ortho-k therapy, future ortho-k lenses should consider applying these designs to obtain a better myopia control effect in children.

Comparison of myopia progression between children wearing three types of orthokeratology lenses and children wearing single-vision spectacles.

To evaluate factors related to myopia progression in children wearing either orthokeratology (OK) lenses or single-vision spectacles (SVS) for 2years. Pooled-analysis retrospective intervention study. This study involved 105 school-aged children wearing SVS who participated in the multi-center Myovision Study and 89 school-aged children wearing one of 3 OK lens types [Menicon Z Night (M, n = 27), αORTHO®-K (A, n = 32), and Emerald™ (E, n = 30)]. In the OK-lens patients, last examination was performed at ≥ 3-weeks post lens-wear discontinuation. Of the subjects, 102 SVS-Group and 79 OK-Group (M: n = 24, A: n = 28, and E: n = 27) children completed all examinations. A relationship between refractive error (RE) change and 7 factors (correction methods, baseline age, baseline RE, baseline axial length, gender, right or left eye, and follow-up period) was derived by multiple regression modeling. Via those same methods, we investigated the relationship between RE change and 7 factors including 3 OK-lens corrections. Related influence factors were correction method (0.85 D myopia reduction in the OK Group, P < 0.001), baseline age (0.16 D myopia reduction in older-age patients, P < 0.001), and baseline RE (0.12 D myopia reduction per 1 D myopia, P = 0.01). No relationship was found between RE change and OK-lens type. No serious adverse events occurred. Regardless of OK lens design, myopia progression in school-aged children was suppressed. The effect was examined not only via axial-length elongation but also RE change, and the myopia control effect by OK lenses was found to be 0.85 D over the 2-year period.