Comparison of Two Main Orthokeratology Lens Designs in Efficacy and Safety for Myopia Control

Clinical Safety and Efficacy of Orthokeratology Contact Lenses With Toric Peripheral Curves: A Review of the Literature

OBJECTIVE

To assess the clinical safety and efficacy of orthokeratology (OK) lenses with toric peripheral curves (TPCs), based on a review of published literature.

METHODS

A literature search on OK lenses with TPCs using 11 relevant search term combinations was conducted. Databases included PubMed, Cochrane Online Library, Prospero International Prospective Register of Systematic Reviews, and Embase. The period covered was January 1, 2012, to May 1, 2024.

RESULTS

In total, 600 publications were identified in the search databases using the search criteria. Based on titles and abstracts, 52 distinct articles were identified for further review; of these, 16 were determined related to clinical evaluation of OK lenses with TPCs. The published studies involved five different lens models from five different manufacturers: Menicon Z Night Toric (Menicon Co, Ltd, Nagoya, Japan), Euclid Emerald Toric (Euclid Systems Corporation, Herndon, VA), Lucid Night Ortho-K Toric (Lucid Korea, Seoul, Korea), Dual Axis Corneal Refractive Therapy (Paragon Vision Sciences, Gilbert, AZ), and Eyebright Base Curve Aspheric Ortho-K (Eyebright Medical Technology Co, Ltd, Beijing, China).

CONCLUSIONS

Published literature suggests that OK lenses with TPCs are effective in treating patients with both myopia and astigmatism, with favorable safety profiles.

Comparison of spectacle lenses with highly aspherical lenslets versus orthokeratology for the management of axial length elongation

CLINICAL RELEVANCE

When selecting an intervention for myopia management, parental inquiries centre around the comparative efficacy of orthokeratology versus myopic defocus spectacle lenses. This prompts an intriguing investigation into the nuanced differences between these two treatment methods.

BACKGROUND

This study aimed to compare the efficacy of spectacle lenses with highly aspherical lenslets (HAL) versus orthokeratology (Ortho-k) in controlling axial length elongation.

METHODS

Electronic medical records of children aged 8 to 14 years who were prescribed either spectacle lenses with HAL or one of the four Ortho-k brands were reviewed. The standardised axial length changes within one year were compared between HAL lenses and Ortho-k lenses with analysis of variance and multivariable regression analysis, adjusting for age, gender, and baseline spherical equivalent.

RESULTS

A total of 308 subjects were included in the analyses. The mean (standard error) of the standardised one-year changes in axial length was 0.12 ± 0.02 mm for HAL, 0.17 ± 0.02 mm for Dreamlite, 0.22 ± 0.02 mm for Alpha, 0.21 ± 0.02 mm for Lucid, and 0.18 ± 0.02 mm for Euclid user cohorts. After adjusting for covariates, the mean differences in axial length growth between HAL and both Alpha and Lucid cohorts were estimated at 0.11 mm (95% CI, 0.03 to 0.19 mm and 95% CI, 0.03 to 0.20 mm). The differences between HAL and Dreamlite or Euclid lenses were not statistically significant. Baseline spherical equivalent demonstrated a significant positive association with axial length growth in Lucid and Euclid lens users.

CONCLUSIONS

Spectacle lenses with HAL design exhibited comparable or superior efficacy in mitigating axial length growth compared to conventional Ortho-k lenses. Furthermore, orthokeratology showed greater efficacy in controlling axial length elongation among individuals with greater baseline myopia.

Effects of different orthokeratology lens designs on slowing axial length elongation in children with myopia

AIM

To elucidate whether differences exist in the impact on retarding the elongation of axial length (AL) among children with myopia when utilizing orthokeratology (ortho-k) lenses employing the corneal refractive therapy (CRT) design versus those employing the vision shaping treatment (VST) design.

METHODS

This retrospective clinical trial aimed to collect and analyze AL data from individuals who wore ortho-k lenses for three years. A total of 654 subjects were enrolled and prescribed one of the three specific brands of ortho-k lenses: CRT, Euclid, and Mouldway. The study's primary focus was to compare the rates of AL elongation and myopic progression across these three brands of ortho-k lenses.

RESULTS

In the 3-year follow-up, the AL elongation exhibited variations of 0.73±0.36 mm in the CRT lens group, 0.59±0.37 mm in the Euclid lens group, and 0.63±0.38 mm in the Mouldway lens group. A noteworthy disparity emerged between the CRT and Mouldway groups (P<0.01), as well as between the CRT and Euclid groups (P<0.001). Additionally, it was observed that 32.1% of participants who wore CRT lenses experienced a decelerated progression of myopia, in contrast to 47.2% in the Euclid group and 44.4% in the Mouldway group. Statistical analyses revealed a statistically significant distinction between the CRT and Euclid groups (P<0.01), and similarly, the CRT group demonstrated a statistically significant difference when compared to the Mouldway group (P<0.05).

CONCLUSION

Ortho-k lenses represent a pragmatic strategy for mitigating the advancement of myopia. In contradistinction to ortho-k lenses utilizing the CRT design, those employing the VST design exhibited a more favorable impact regarding retarding AL elongation.

Testing the homogeneity of odds ratio across strata for combined bilateral and unilateral data

Bilateral and unilateral combined data are commonly involved in clinical trials or observational studies designed to test the treatment effectiveness on paired organs or bodily parts within individual subjects. It is essential to examine if the treatment effect is consistent across different subgroups such as age, gender, or disease severity for understanding how the treatment works for various patient populations. In this paper, we propose three large-sample homogeneity tests of odds ratio in the stratified randomization setting using correlated combined data. Our simulation results show that the score test exhibits robust empirical type I error control and demonstrates strong power characteristics compared to other methods proposed. We apply the proposed tests to real-world datasets of acute otitis media and myopia to illustrate their practical application and utility.

Comparison of the long-term effects of atropine in combination with Orthokeratology and defocus incorporated multiple segment lenses for myopia control in Chinese children and adolescents

PURPOSE

The aim of this study was to evaluate the efficacy of Orthokeratology (Ortho-K), defocus incorporated multiple segment (DIMS) lens, combined Ortho-K/atropine, and combined DIMS/atropine for myopia control in children.

METHODS

A retrospective study included 167 myopic children aged 6-14 years with a spherical equivalent refraction (SER) of -0.75 to -4.00 diopter treated with Ortho-K (OK, n = 41), combined Ortho-K/atropine (OKA, n = 43), DIMS (n = 41), or combined DIMS/atropine (DIMSA, n = 42). Axial length (AL) was measured at baseline and at 3, 6, 9 and 12 months. Axial elongation over time and between groups were analysed.

RESULTS

After 12 months, the AL change was 0.20 ± 0.12 mm, 0.12 ± 0.14 mm, 0.22 ± 0.14 mm, and 0.15 ± 0.15 mm in the OK, OKA, DIMS, and DIMSA, respectively. There was no significant difference in AL change between OK and DIMS. OKA and DIMSA significantly slowed axial elongation compared to OK and DIMS monotherapy. After stratification by age, in the subgroup aged 6-10 years, there was significant difference in AL change between OKA and DIMS (p = 0.013), and no difference between other groups, while in the subgroup aged 10-14 years, the difference between OKA and DIMS became insignificant (p = 0.237), and the difference between OK and OKA, OK and DIMSA, DIMS and DIMSA became significant.

CONCLUSIONS

Ortho-K and DIMS lenses show similar reductions in myopia progression among children with low initial myopia. Atropine can significantly improve the efficacy of myopia control of both Ortho-K and DIMS lenses, and this add-on effect is better in older children.

Short-term Changes in Epithelial and Optical Redistribution Induced by Different Orthokeratology Designs

OBJECTIVES

This study aimed to investigate corneal epithelial and topographic changes caused by two commercial myopia orthokeratology (ortho-k) designs.

METHODS

Twenty-six subjects fitted with vision shape treatment (VST) lenses and 30 subjects fitted with corneal reshaping therapy (CRT) lenses were reviewed 1 day, 1 week, and 1 month after lens initiation. A spectral-domain optical coherence tomography system was used to create epithelial maps that were in turn used to determine the average epithelial thickness of each zone and the diameter of treatment zone. By measuring the topographic tangential differential map, the treatment zone diameter and the power and width of the high convex zone (HCZ) were obtained. All epithelial thicknesses and topographic corneal variations recorded were analyzed.

RESULTS

At the central zone, the epithelial thickness changes (△ET) decreased significantly after 1 day of ortho-k in two groups. At 2- to 9-mm peripheral zone, ortho-k increased △ET until 1 week in the VST group, whereas it kept increasing in the CRT group after 1 week. At 1 month, the central △ET is -9.51±2.38 mm in the VST group, which was comparable to -8.72±3.43 mm in the CRT group. The nasal HCZ power and the △ET of nasal and inferior nasal were significantly larger in the CRT group. A positive correlation was found between the HCZ power and △ET generated by VST-type lenses inferiorly and temporally. For the CRT group, a positive correlation was found between inferior HCZ power and △ET.

CONCLUSIONS

At the early stage of ortho-k, epithelial thickness and topography change quickly and simultaneously. Epithelial changes were in line with corneal topography reshaping. Epithelial and optical remodelling were affected by different lens types.

Study on Related Factors of the Treatment Zone After Wearing Paragon CRT and Euclid Orthokeratology Lenses

OBJECTIVE

To explore the influence factors of the treatment zone diameter (TZD) and its relationship with axial length growth (ALG) after wearing Paragon CRT and Euclid orthokeratology lenses.

METHODS

The right eye data of myopic patients wearing Paragon CRT and Euclid orthokeratology in the ophthalmology department of The First Affiliated Hospital of Soochow University were retrospectively reviewed from April 2019 to October 2022. The TZD and ALG were compared between the Paragon CRT and Euclid groups. The correlation factors of TZD after wearing lens for 1 month and the relationship between the overlapping treatment zone-to-pupil area ratio and the ALG after wearing lens for 1 year were analyzed between the two groups.

RESULTS

There were 160 patients (160 eyes) in the Paragon CRT group and 155 patients (155 eyes) in the Euclid group. After wearing lens for 1 month, the TZD in the Paragon CRT group (3.72±0.37 mm) was larger than that in the Euclid group (3.26±0.37 mm) ( P <0.001). The stepwise multivariate linear regression analysis showed that the eccentricity at the flattest meridians (Em) and the central corneal thickness were correlated with the TZD in both groups ( P <0.05). After wearing lens for 1 year, the ALG in the Paragon CRT group (0.32±0.20 mm) was larger than that in the Euclid group (0.25±0.20 mm) ( P =0.001). The stepwise multivariate linear regression analysis showed that the initial wearing age and the overlapping treatment zone area-to-pupil area ratio were correlated with the ALG in both groups ( P <0.05).

CONCLUSION

For both the Paragon CRT and Euclid orthokeratology, the wearers with thicker central corneal thickness and smaller Em usually had a smaller TZD. In both groups, the overlapping treatment zone area-to-pupil area ratio was correlated with the ALG.

Comparison of two different orthokeratology lenses and defocus incorporated soft contact (DISC) lens in controlling myopia progression

BACKGROUND

To compare axial elongation in 8-11-year-old myopes wearing orthokeratology (OK) lenses with different back optic zone diameters (BOZD), defocus incorporated soft contact (DISC) lenses, and single-vision soft contact lenses (SCLs).

METHODS

A total of 122 children (aged 8-11 years) with spherical equivalent refraction (SER) between - 1.00 D and - 4.00 D were enrolled in this prospective study and randomly assigned to four groups: 5.0 mm-BOZD OK, 6.2 mm-BOZD OK, DISC, and single-vision SCLs. Children in each group were further divided into subgroups stratified by the average baseline SER: low myopic eyes (SER: - 1.00 D to - 2.50 D) and moderate myopic eyes (SER: - 2.50 D and over). Axial length (AL) was measured at baseline and after one year.

RESULTS

The 5.0 mm-BOZD OK, 6.2 mm-BOZD OK, and DISC groups exhibited significantly slower AL elongation than the SCL group. The proportion of slow progressors (AL elongation ≤ 0.18 mm/year) in the first three groups was 42%, 23%, and 29%, respectively. Furthermore, one-year AL elongation was significantly smaller in the 5.0 mm-BOZD OK group compared with the 6.2 mm-BOZD OK group. Regardless of SER, children in the 5.0 mm-BOZD OK and DISC groups showed comparably slower AL elongation than those in the SCL group. However, fitting with 6.2 mm-BOZD OK lenses significantly retarded AL elongation in moderate myopic eyes, but not in low myopic eyes.

CONCLUSIONS

Overall, 5.0 mm-BOZD OK lenses, 6.2 mm-BOZD OK lenses, and DISC lenses were effective in retarding AL elongation in 8-11-year-old myopes compared with single-vision SCLs, but for children with SER less than - 2.50 D, fitting with 5.0 mm-BOZD OK lenses and DISC lenses yielded better myopia control efficacy compared to wearing single-vision SCLs or 6.2 mm-BOZD OK lenses.

Choroidal vasculature act as predictive biomarkers of long-term ocular elongation in myopic children treated with orthokeratology: a prospective cohort study

BACKGROUND

Despite receiving orthokeratology (ortho-k), the efficacy of retarding ocular elongation during myopia varies among myopic children. The current study aimed to investigate the early changes of choroidal vasculature at one month after ortho-k treatment and its association with one-year ocular elongation, as well as the role of such choroidal responses in predicting the one-year control efficacy of ortho-k treatment.

METHODS

A prospective cohort study was conducted in myopic children treated with ortho-k. Myopic children aged between 8 and 12 years who were willing to wear ortho-k lenses were recruited consecutively from the Eye Hospital of Wenzhou Medical University. Subfoveal choroidal thickness (SFCT), submacular total choroidal luminal area (LA), stromal area (SA), choroidal vascularity index (CVI), choriocapillaris flow deficit (CcFD) were evaluated by optical coherence tomography (OCT) and OCT angiography over a one-year period.

RESULTS

Fifty eyes from 50 participants (24 males) who finished one-year follow-ups as scheduled were included, with a mean age of 10.31 ± 1.45 years. The one-year ocular elongation was 0.19 ± 0.17 mm. The LA (0.03 ± 0.07 mm²), SA (0.02 ± 0.05 mm²) increased proportionally after one-month of ortho-k wear (both P < 0.01), as did the SFCT (10.62 ± 19.98 μm, P < 0.001). Multivariable linear regression analyses showed that baseline CVI (β = - 0.023 mm/1%, 95% CI: - 0.036 to - 0.010), one-month LA change (β = - 0.009 mm/0.01 mm², 95% CI: - 0.014 to - 0.003), one-month SFCT change (β = - 0.035 mm/10 µm, 95% CI: - 0.053 to - 0.017) were independently associated with one-year ocular elongation during ortho-k treatment after adjusting with age and sex (all P < 0.01). The area under the receiver operating characteristic curve of prediction model including baseline CVI, one-month SFCT change, age, and sex achieved 0.872 (95% CI: 0.771 to 0.973) for discriminating children with slow or fast ocular elongation.

CONCLUSIONS

Choroidal vasculature is associated with ocular elongation during ortho-k treatment. Ortho-k treatment induces increases in choroidal vascularity and choroidal thickness as early as one month. Such early changes can act as predictive biomarkers of myopia control efficacy over a long term. The utilization of these biomarkers may help clinicians identify children who can benefit from ortho-k treatment, and thus has critical implications for the management strategies towards myopia control.

Factors influencing axial elongation in myopic children using overnight orthokeratology

Several factors influence axial length in children with myopia treated using overnight orthokeratology. To identify these factors, this retrospective study collected axial length and corneal aberration data on 78 eyes before and 1-year after orthokeratology. Patients were divided according to axial elongation (cut-off, 0.25 mm/year). Baseline characteristics included age, sex, spherical equivalent refraction, pupil diameter, axial length, and orthokeratology lens type. Corneal shape effects were compared through tangential difference maps. Group differences in higher-order aberrations of a 4 mm zone were compared at baseline and 1-year following therapy. Binary logistic regression analysis was conducted to identify the variables determined for axial elongation. Significant differences between both groups included the initial age of wearing orthokeratology lenses, type of orthokeratology lens, size of central flattening area, corneal total surface C12 (1-year), corneal total surface C8 (1-year), corneal total surface spherical aberration (SA) (1-year root mean square [RMS] values), change in total corneal surface C12, and change in front and total corneal surface SA (RMS values). The age when wearing an orthokeratology lens was the most important factor influencing axial length in children with orthokeratology-treated myopia, followed by lens type and change in the C12 of the total corneal surface.