Efficacy, predictability and safety of long-term orthokeratology: An 18-year follow-up study

Long-term effect of orthokeratology on controlling myopia progression in children with allergic conjunctivitis

BACKGROUND

To observe whether the effect of orthokeratology (OK) lenses on myopia control in children with allergic conjunctivitis (AC) after three years of wear differs from that in children without allergic conjunctivitis (nAC) and to identify the potential influencing factors.

METHODS

This was a retrospective case-control study. Patients aged 8-15 years who were fitted with OK lenses in 2019 were collected. A three-year follow-up was also conducted, documenting all corneal adverse events (AEs) and the increase in axial length (AL) of the eye after three years of wearing OK lenses. Patients were divided into groups with and without AC based on their medical history and physical signs at the initial fitting. Baseline data and AL elongation after three years were compared between the two groups.

RESULTS

A total of 309 patients were included in this study, with 47 in the AC group and 262 in the nAC group. There were no statistically significant differences between the two groups in terms of age, sex, spherical equivalent (SE), AL of the eye and environment. After three years of OK lens wear, the AL elongation in the AC group was 0.96 ± 0.45 mm, whereas it was 0.69 ± 0.45 mm in the nAC group (P < 0.001). The extent of AL elongation in AC patients was significantly greater than that in nAC patients. During the three-year follow-up period, the duration of OK lenses discontinuation due to corneal AEs in the AC group was greater than that in the nAC group (P < 0.05).

CONCLUSIONS

This study found that allergic conjunctivitis can affect the efficacy of OK lenses in controlling myopia after three years of treatment.

Daily Low-Level Red Light for Spherical Equivalent Error and Axial Length in Children With Myopia: A Randomized Clinical Trial

Importance

Treatments are needed to slow progression of or reduce incidence of myopia.

Objective

To evaluate the efficacy and safety of daily 650-nm low-level red light (LLRL) for myopia treatment.

Design, Setting, and Participants

Single-masked, randomized clinical trial at 1 site in China. Baseline measurements were completed from August to September 2021. Participants were children aged 6 to 12 years with spherical equivalent error (SER) of -6 diopters (D) to 3 D. Data were analyzed from March to July 2023.

Interventions

Irradiation daily with 650-nm LLRL for 3 minutes twice daily 4 or more hours apart or no intervention.

Main Outcomes and Measures

Primary outcomes were changes in cycloplegia SER and axial length (AL) at 6- and 12-month follow-up visits. Safety was assessed on masked fundus photograph evaluations.

Results

A total of 336 children were randomly allocated into the LLRL group or control group in a 1:1 ratio. The control group contained 86 female patients (51.2%), and the treatment group contained 90 female patients (53.6%). The mean (SD) age, SER, and AL were 9.0 (1.9) years, -1.3 (1.5) D, and 23.8 (1.0) mm for all patients. A total of 161 (95.8%) in the LLRL group and 159 (94.6%) in the control group returned for the 6-month follow-up. A total of 157 (93.5%) in the LLRL group and 152 (90.5%) in the control group returned for the 12-month follow-up. Mean (SD) changes in SER were 0.15 (0.16) D and -0.26 (0.21) D for the LLRL group and the control group, respectively (difference, -0.41 D; 95% CI, -0.48 to -0.34 D; P < .001), at 6 months and 0.24 (0.27) D and -0.65 (0.33) D for the LLRL group and the control group, respectively (difference, -0.89 D; 95% CI, -0.95 to -0.83 D; P < .001), at 12 months. Mean (SD) changes in AL were -0.06 (0.08) mm and 0.13 (0.12) mm for the LLRL group and control group, respectively (difference, 0.19 mm; 95% CI, 0.16 to 0.22 mm; P < .001), at 6 months and -0.11 (0.10) mm and 0.26 (0.16) mm for the LLRL group and control group, respectively (difference, 0.37 mm; 95% CI, 0.34 to 0.40 mm; P < .001). Masked fundus photograph review did not identify retinal changes in either group.

Conclusions and relevance

These findings suggest daily use of 650-nm LLRL for 1 year can slow progression of SER and AL without safety concerns identified. Confirmation of these findings at independent sites seems warranted, as well as determining whether these effects can be sustained with or without continued treatment and whether LLRL has any effect on pathological myopia.

Trial Registration

ChiCTR2200058963.

Development and psychometric evaluation of beliefs about the orthokeratology lens compliance scale (BOLCS): Based on the theory of planned behavior

PURPOSE

Non-adherence to standard wear, care, and follow-up procedures is a major risk factor for contact lens-related complications. The effectiveness of orthokeratology largely depends on the wearer's adherence. However, a deficiency in scales capturing adherence beliefs pertinent to orthokeratology exacerbates the lack of guidance for effective intervention strategies. The purpose of this study is to develop and evaluate the psychometric properties of a new scale based on the Theory of Planned Behavior that assesses the level of adherence among ortho-k wearers.

METHODS

This study involved three stages following the STROBE checklist: (1) developing initial scale items based on the Theory of Planned Behavior, a literature review, and a qualitative study; (2) evaluation of content and face validity; (3) psychometric testing on 296 participants. Item analysis, based on Classical Test Theory, assessed the overall consistency, reliability, and validity of the scale.

RESULTS

The final 37-item Beliefs about the Orthokeratology Lens Compliance Scale (BOLCS) comprises 11 dimensions. The Cronbach's alpha coefficients for each dimension ranged from 0.560 to 0.798. The folded half reliabilities were 0.845, and the combined reliabilities ranged from 0.676 to 0.793, indicating strong reliability. Item-level CVI (I-CVI) and scale-level CVI/average (S-CVI/Ave) values, assessed by the panel, ranged from 0.71 to 1 and 0.954, respectively. Exploratory and confirmatory factor analyses supported a factor structure consistent with the theoretical model.

CONCLUSIONS

The scale's construction adhered to a standardized process, yielding preliminary validation results with satisfactory reliability and validity.

Systematic Review of Myopia Progression after Cessation of Optical Interventions for Myopia Control

Despite high discontinuation rates for myopia optical interventions, limited attention has been given to the potential rebound effects post-discontinuation. This systematic review aims to assess the extent of the rebound effects following the cessation of common clinical optical myopia-control interventions in children. A comprehensive search of PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov was conducted from inception to October 2023. The rebound effects, defined as changes in the axial length or spherical equivalent during and after treatment cessation, were categorized into four levels. These studies encompassed 703 participants and spanned from 2019 to 2023, with durations of treatment and cessation ranging from 6 months to 3.5 years and from 2 weeks to 5 years, respectively. This review, encompassing 14 studies, revealed a predominant strong rebound effect in orthokeratology (8 studies), a weak rebound effect in multifocal soft contact lenses (4 studies), and a variable rebound effect in peripheral-plus spectacle lenses (2 studies). Notably, with the increasing cessation duration, the rebound effects diminished, potentially linked to the reversal of choroidal thickening and the disappearance of peripheral myopic defocus. In conclusion, a temporal trend of rebound effects exists in all three myopia optical interventions, possibly contributing to their myopia control mechanisms.

Two-Dimensional Peripheral Refraction and Higher-Order Wavefront Aberrations Induced by Orthokeratology Lenses Decentration

Purpose

The purpose of this study was to explore two-dimensional peripheral refraction and higher-order aberrations (HOAs) induced by orthokeratology lens decentration.

Methods

Two-dimensional peripheral refraction and HOAs in a rectangular field (horizontally 60 degrees and vertically 36 degrees) were obtained using an open-view Hartmann-Shack wavefront sensor. The peripheral field was divided into 8 regions according to a combination of superior (UZ) or inferior (LZ) and a value, 1 (T25 to T30), 2 (T20 to T25), 3 (N20 to N25), or 4 (N25 to N30). The decentration of the lens was evaluated based on the change of power in the front of the tangential corneal map. All measurements were taken at the baseline and 1 month after lens fitting.

Results

In total, 134 myopic children (age = 12.47 ± 1.70 years, SER = -2.44 ± 1.10 diopters [D]) were recruited. In general, horizontally asymmetrical change was observed in relative peripheral refraction (RPR), spherical aberration (SA), and horizontal coma. The root-mean square of higher order aberration (RMSHOA) and vertical coma demonstrated radial symmetrical change and vertically asymmetric change, respectively. Relative peripheral myopia was significantly increased after the treatment, with more myopic refraction in the temporal side. RPR changes in UZ2, UZ3, UZ4, LZ1, and LZ2 were related to the amount of lens decentration (r ≈ 0.4, P < 0.05). All HOAs increased after lens fitting (around 0.03 um, 0.02 um, 0.04 um, and 0.41 um for SA, horizontal COMA, vertical COMA, and RMSHOA in the periphery region).

Conclusions

RPR and HOAs are related to lens decentration, which might contribute to the efficacy of orthokeratology.

Translational Relevance

The study found a decentration-related optical feature after 1 month of lens wear, which is a suggested protective factor in myopia treatment. The findings might provide new insights for customized contact lens myopia treatment based on optics.

Modeling and Prediction of the Immediate and Short-Term Effect of Myopic Orthokeratology

PURPOSE

To characterize the clinical changes occurring in the initial phase of the orthokeratology (OK) treatment for myopia correction, developing a model of prediction of the refractive changes in such phase.

METHODS

Prospective study enrolling 64 eyes of 32 patients (range, 20-40 years) undergoing myopic OK treatment with the reverse geometry contact lens CRT (Paragon Vision Science). Changes in uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), refraction, corneal topography, ocular aberrations, and corneal epithelial thickness were evaluated during the first hour of OK lens wear and after 1 week of OK treatment. Multiple linear regression analysis was used to obtain a model to predict the short-term refractive effect of OK.

RESULTS

The UCVA improved at each visit, reaching normal visual acuity values after a week (P<0.001) of OK treatment, which was consistent with the significant spherical equivalent (SE) reduction and central flattening (P<0.001). Multiple linear regression analysis revealed that one night change in refraction (ΔR×1N) could be predicted according to the following expression (P<0.001, R2=0.686): ΔR×1N=1.042+0.028×Age+1.014×BCET (baseline central epithelium thickness)-0.752×BKm (baseline mean keratometry)-1.405×BSE (baseline SE)+1.032×ΔR×1 h (change in SE after 1 hr of OK lens use). Similarly, a statistically relevant linear relationship was obtained for predicting the refractive change after 1 week (ΔR×1W) of OK use (P<0.001, R2=0.928): ΔR×1W=3.470-1.046×BSE-1.552×BBCVA (baseline BCVA)-0.391×BKm+0.450×ΔR×1 h.

CONCLUSIONS

The immediate and short-term refractive effects of myopic OK with the reverse geometry contact lens CRT can be predicted with enough accuracy from baseline and first trial visits data.

Topical Review: Studies on Management of Myopia Progression from 2019 to 2021

SIGNIFICANCE

Myopia is a common eye condition that increases the risk of sight-threatening complications. Each additional diopter increases the chance of complications. The purpose of this review was to make an overview of myopia control treatment options for children with myopia progression.In this nonsystematic review, we searched PubMed and Cochrane databases for English-language studies published from 2019 to September 2021. Emphasis was given to selection of randomized controlled trials. Nineteen randomized controlled trials and two retrospective studies were included. Topical atropine and orthokeratology remain the most used treatments, whereas lenses with novel designs are emerging treatments. Overall myopia progression in the treatment groups for low-dose atropine and orthokeratology was lower than in the control groups, and their efficacy was reported in several randomized controlled trials and confirmed by various systematic reviews and meta-analysis. The findings of myopia progression and axial elongation for the MiSight, defocus incorporated multiple segment spectacle lens, highly aspherical lenslets, and diffusion optics technology spectacle lens were comparable. Public health interventions to optimize environmental influences may also be important strategies to control myopia. Optimal choice of management of myopia depends on treatment availability, acceptability to child and parents, and specific patient features such as age, baseline myopia, and lifestyle. Eye care providers need to understand the advantages and disadvantages of each therapy to best counsel parents of children with myopia.

Effect of low-dose atropine eyedrops on pupil metrics: results after half a year of treatment and cessation

Purpose

To evaluate the effect of low-dose atropine eyedrops on pupil metrics.

Methods

This study was based on a randomized, double-masked, placebo-controlled, and cross-over trial in mainland China. In phase 1, subjects received 0.01% atropine or placebo once nightly. After 1 year, the atropine group switched to placebo (atropine-placebo group), and the placebo group switched to atropine (placebo-atropine group). Ocular parameters were measured at the crossover time point (at the 12th month) and the 18th month.

Results

Of 105 subjects who completed the study, 48 and 57 children were allocated into the atropine-placebo and placebo-atropine groups, respectively. After cessation, the photopic pupil diameter (PD) and mesopic PD both decreased (− 0.46 ± 0.47 mm, P < 0.001; − 0.30 ± 0.74 mm, P = 0.008), and the constriction ratio (CR, %) increased (4.39 ± 7.54, P < 0.001) compared with values at the crossover time point of the atropine-placebo group; pupil metrics of the atropine-placebo group had no difference from the values at the crossover time point of the placebo-atropine group. After 6 months of treatment, the photopic PD and the mesopic PD increased (0.54 ± 0.67 mm, P < 0.001; 0.53 ± 0.89 mm, P < 0.001), the CR (%) decreased (− 2.53 ± 8.64, P < 0.001) compared with values at the crossover time point of the placebo-atropine group. There was no significant relationship between pupil metrics and myopia progression during 0.01% atropine treatment.

Conclusion

Pupil metrics and the CR could return to pre-atropine levels after cessation. Pupil metrics had no significant effect on myopia progression during treatment.

Analysis of the Reasons for the Discontinuation of Orthokeratology Lens Use: A 4-Year Retrospective Study

PURPOSE

Although orthokeratology has a positive effect on myopia control, some patients discontinue orthokeratology lens use. This study analyzed the data of all patients who had been fitted with an orthokeratology lens in the past 4 years and the reasons for discontinued lens use, with the aim of improving the prevention and control of myopia.

METHODS

This retrospective study analyzed the data of patients, aged 8 to 18 years, fitted with orthokeratology lenses from 2017 to 2020. The ametropic spherical lens powers ranged from -6.00 D to -0.75 D, and the cylindrical lens powers were all more than -1.50 D. The reasons for discontinuation of lens wear were analyzed and compared. The period of lens wear (median [range]) was 24 (13.5-34.5) months.

RESULTS

A total of 2,499 patients' files were retrieved. The duration of lens wear was 24 (13.5-34.5) months. A total of 50 patients discontinued lens use, including 25 patients (50.0%) who could not adhere to lens use for various reasons, nine patients (18.0%) with a short sleep time, eight patients (16.0%) with economic difficulties, and five patients (10.0%) who experienced a poor effect after wearing the lenses. Corneal infiltrates affected lens use in three patients (6.0%). In addition, 30 patients underwent surgical correction when they reached adulthood.

CONCLUSION

Although orthokeratology lenses are effective and safe, there are still a small number of patients who discontinued lens use for various reasons. Adherence and precautions should be emphasized during the process.

Assessment of Satisfaction, Compliance and Side Effects among Long-Term Orthokeratology Wearers

Purpose: This study aims to assess the satisfaction, compliance, and side effects among the long-term orthokeratology (Ortho-K) users in a tertiary hospital in Taiwan and analyze the side effects and related risk factors. Methods: Children and their guardians were assessed using a structured and validated questionnaire inquiring about background information, wear and care behaviors, daily activities, satisfaction, and related concerns. Clinical information, including refractive data and side effects, was obtained through patient medical files. Results: Three hundred and five school-aged patients were enrolled, and the average age was 13.13 ± 3.39 years, with an average wearing period of 17.1 ± 8.1 months. Over 83% of the subjects had clear daytime vision all day, around 88% felt satisfied or very satisfied with the results, and 98% exhibited a willingness to continue wearing the Ortho-K lenses. Most guardians (83%) were pleased with the controlling effect of myopic progression. Initial spherical equivalent and regular cleaning of the lens protein significantly correlated with clear day vision. Wearing >6 days/week correlated with less risk of lens binding. Based on the questionnaire, the main reasons for using Ortho-K were effectiveness, safety, and practicality, while the major concerns were discomfort, harmful to the eyes, and no effect. Conclusion: With a comprehensive care program from practitioners and good compliance of users, Ortho-K could be the most effective and satisfactory option for myopic children in Taiwan.