Orthokeratology for high myopia

To report the effect of stopping orthokeratology (ortho-k) lens wear on the changes in refractive errors and axial elongation in a girl who has been wearing ortho-k lenses for myopic control for over 2 years. A girl with a history of fast myopic progression enrolled in ortho-k treatment when she was 6 years old. She switched to spectacle wear after receiving ortho-k treatment for 38 months and then switched back to ortho-k lens wear. Refractive errors and axial lengths were monitored for 8 months with ortho-k lens wear, followed by about 6½ months of lens discontinuation and spectacle wear, and finally another 6 months of resumed ortho-k lens wear. The residual refractive errors in the 8 months before discontinuation of ortho-k lens wear were not more than ±0.25 diopter (D) and -0.50 D in spherical and cylindrical powers, respectively, and the average increases in axial length were 0.02 mm (OD) and 0.03 mm (OS) per month. Myopia increased by 0.75 D (OD) and 1.25 D (OS) during the lens discontinuation period, with corresponding axial elongations of 0.06 mm (OD and OS) per month. No significant changes were observed in axial elongation or residual refractive errors during the 6-month period of resumed lens wear. When a child who had been wearing ortho-k lenses for myopic control for over 2 years ceased lens wear, small net amounts of axial elongation were observed during the subsequent months with spectacle wear. These changes took place at a faster rate relative to the ortho-k lens wear period. Ortho-k lens wear appeared to slow myopic progression for this child.

This study aimed to compare the efficacy and safety of four types of orthokeratology (OK) lenses (CRT, Lucid, Euclid, and IBright) in controlling mild to moderate myopia progression among children and adolescents over 36 months. This retrospective study analyzed clinical records of 219 children (438 eyes) who wore OK lenses for 36 months. Clinical data for the four commonly used OK lenses were collected and analyzed using one-way analysis of variance (ANOVA) and Pearson's chi-squared test. At baseline, no significant differences were observed among the four groups in terms of age, sex, spherical equivalent, corneal curvature, or corneal thickness (all P > 0.05). All OK lenses effectively controlled myopia progression over the observation period, with axial length changes not exceeding 1.0 mm. At the 36-month follow-up, the IBright group showed the largest flat keratometry (K1) curvature change at 3 months (-2.40 ± 0.97 D), while other groups showed no significant differences at subsequent time points. In terms of steep keratometry (K2) curvature, the Lucid group exhibited the largest change at 24 months (-3.07 ± 1.50 D), but no significant differences were observed among groups at other time points. Axial length changes showed no statistically significant differences among the four OK lenses across follow-up visits (P > 0.05). Subgroup analysis indicated greater axial elongation in children under 12 years old compared to those over 12 years. Among children with corneal thickness less than 530μm, the CRT group demonstrated the largest K1 curvature change. The incidence of adverse events was comparable across groups (P > 0.05). All four OK lenses demonstrated comparable efficacy and safety in controlling myopia progression, providing effective treatment options for children and adolescents with mild to moderate myopia. However, differences in curvature changes and age-related effects warrant further attention.

BackgroundMany efforts have been invested in slowing progression of myopia. Among the methods, atropine administration and orthokeratology (OK) are most widely used. This study analyzed the efficacy of atropine and OK lens in controlling myopia progression and elongation of axial length.MethodsThis retrospective study included 105 patients (210 eyes) who wore OK lenses and 105 patients (210 eyes) who applied 0.125% atropine every night during the 3 following period. Student t-test, linear regression analysis, repeated measure ANOVA, and Pearson’s correlation coefficient were used for statistical analysis.ResultsThe change in axial length per year was 0.28 ± 0.08 mm, 0.30 ± 0.09 mm, and 0.27 ± 0.10 mm in the OK lens group, and 0.38 ± 0.09 mm, 0.37 ± 0.12 mm, and 0.36 ± 0.08 mm in the atropine group for years 1, 2, and 3, respectively. Linear regression analysis revealed an increase in myopia of 0.28 D and 0.34 D per year, and an increase in axial length of 0.28 mm and 0.37 mm per year in the OK lens and atropine groups, respectively. Repeated measure ANOVA showed significant differences in myopia (p = 0.001) and axial length (p < 0.001) between the atropine and OK lens groups; in astigmatism, there was no significant difference in these parameters (p = 0.320). Comparison of increases in axial length in relation to baseline myopia showed significant correlations both in the OK lens group (Pearson’s correlation coefficient, r = 0.259; p < 0.001) and atropine group (r = 0.169; p = 0.014). High myopia patients benefited more from both OK lenses and atropine than did low myopia patients. The correlation of baseline myopia and myopia progression was stronger in the OK lens group then in the atropine group.ConclusionsOK lens is a useful method for controlling myopia progression even in high myopia patients.

Clinical relevance Orthokeratology (OK) lens is commonly used to control myopia progression of children. Understanding the relationship between relative peripheral refraction (RPR) and the growth rate of axial length (AL) may assist in explaining myopic progression. Background The aim of this work is to investigate the RPR in myopic children wearing OK lenses, and to evaluate its relationship with the growth rate of AL. Methods RPRs of 31 children wearing OK lenses and 31 children wearing single-vision glasses were measured with multispectral refraction topography (MRT). MRT shows the total RPR (TRPR), RPR in the superior area (RPR-S), RPR in the inferior area (RPR-I), RPR in the temporal area (RPR-T) and RPR in the nasal area (RPR-N), respectively. It also shows RPR in the visual field of 15° (RPR-15), 30° (RPR-30) and 45° (RPR-45), respectively. RPRs in the visual field from 15° to 30°, 30° to 45° and 15° to 45° are recorded as RPR-(30–15), RPR-(45–30) and RPR-(45–15), respectively. According to the growth rate of AL, children wearing OK lenses were further divided into slow and fast growth groups. Results TRPR, RPR-I, RPR-T, RPR-N, RPR-15, RPR-30, RPR-45, RPR-(30–15), RPR-(45–30), and RPR-(45–15) of children in the OK lens group were significantly smaller than in the control group (all P < 0.05). TRPR, RPR-N, RPR-15, RPR-30, RPR-45, RPR-(30–15), and RPR-(45–15) of the slow growth group were significantly smaller than in the fast growth group (all P < 0.05). The growth rate of AL were positively correlated with TRPR (R = 0.383, P = 0.040), RPR-N (R = 0.395, P = 0.034), RPR-30 (R = 0.408, P = 0.028), RPR-45 (R = 0.377, P = 0.044), RPR-(30–15) (R = 0.390, P = 0.036). Conclusions RPRs of children show relative myopic defocus after wearing OK lenses. Furthermore, the growth rate of AL is smaller with more negative RPR.

Comparison of the efficacy of orthokeratology and highly aspherical lenslets in slowing myopia progression.

To compare isolation of staphylococci from periorbital tissues and accessories of orthokeratology (ortho-k) lens and spectacle wearers and investigate prevalence of antiseptic-resistance (QAC) genes. To determine minimum inhibitory concentrations (MIC) of antiseptics and antibiotic susceptibility of isolates. Staphylococci were isolated from eyelids, eyelashes, and conjunctival sacs of 23 ortho-k lens wearers and 20 spectacle wearers. Samples were also collected from ortho-k lenses, lens cases, and spectacle frames. Isolations of Staphylococcus aureus were compared between ortho-k subjects and controls for all samples and for coagulase-negative staphylococci (CNS) from conjunctival sacs. QAC genes were amplified in 110 S. aureus and 59 CNS isolates and prevalence compared in isolates from ortho-k lens and spectacle wearers. Associations were assessed between presence of QAC genes and antibiotic and antiseptic susceptibility. Although isolation of S. aureus did not differ significantly in periorbital samples from ortho-k and control subjects, QAC genes were significantly more common in both S. aureus and CNS from ortho-k subjects (odds ratio 4.4 and 10.74, respectively). Overall, qacA/B was the predominant gene detected, being present in 26.5% CNS and 11% S. aureus. smr and qacH were present in 12% of CNS, but were less common in S. aureus. QAC gene-positive isolates had higher MICs to benzalkonium chloride and chlorhexidine digluconate. Our results suggest that long-term use of multipurpose solutions containing quaternary ammonium compounds may select for carriage of organisms harboring QAC genes. As these genes are associated with antibiotic resistance, their increased prevalence in isolates from contact lens wearers is a concern.

The purpose of this study was to conduct a meta-analysis comparing rigid gas permeable lenses (RGP) with soft contact lenses (SCL), spectacles and orthokeratology (OK) lenses for myopia control with respect to axial length elongation, spherical equivalent and measures of corneal curvature. Medline, Cochrane, EMBASE, and Google Scholar databases were searched to September 29, 2015 using the following keywords: rigid gas permeable contact lens; refractive error; and refractive abnormalities. Randomized controlled trials, two-arm prospective studies and retrospective studies of children with myopia treated with RGP lenses compared with spectacles, SCL, and OK lenses were included. Outcome measures were changes of axial length, spherical equivalent, flatter meridian, steeper meridian and corneal apical radius. Five studies were included. Three studies reported axial length change after 2-3 years of treatment with RGP lenses and SCL/spectacles and no difference between the groups was noted (pooled mean difference = -0.077, 95% confidence interval [CI]: -0.120 to 0.097, p = 0.840). Two studies reported a change of spherical equivalent after 2-3 years of treatment with RGP lenses and SCL/spectacles, and no difference between the groups was noted (pooled mean difference = 0.275, 95% CI: -0.390 to 0.941, p = 0.417). Two studies compared corneal curvature measures between RGP and OK lenses after 3-6 months of treatment and no differences in any measures of corneal curvature were seen. The effect of RGP lenses and SCL/spectacles on axial length elongation and spherical equivalent and of RGP and OK lenses on corneal curvature in children with myopia was similar.

The aim of this study is to review the current literature on ortho-K lenses use in myopia with a particular focus on the efficacy and safety of orthokeratology in myopia, and its effects in the case of high myopia, as well as the impact of COVID-19 pandemic on myopia and orthokeratology. COVID-19 pandemic influenced the incident of myopia as well as progression of myopia. Ortho-K lenses have been shown to be safe and effective in reducing the axial elongation and decreasing myopia progression in low to moderate myopia and with some limitations in high myopia patients. During the COVID-19 pandemic, ortho-K treatment was not affected, and the pandemic had no effect on the axial elongation in myopia children undergoing treatment with ortho-K lenses. Myopia is becoming a major health problem worldwide that is increasing to an alarming rate. The progression of myopia can lead to serious irreversible complications. There is sufficient evidence proving that orthokeratology lenses are effective and safe in myopia. More studies need to be done in high myopia. Long term success of the use of ortho-k lenses increases with the proper lens fitting.

The global increase in myopia prevalence and associated secondary complications necessitates adequate monitoring of myopia progression. This review highlights the advantages and disadvantages of the most commonly used target parameters for assessing myopia progression: refractive error and axial length. Although refractive error is essential for the diagnosis and optical correction of myopia, axial length proves to be amore reliable and clinically relevant parameter for monitoring progression and guiding preventive interventions. Axial length correlates more strongly with the risk of ocular complications and is less susceptible to diurnal variations and interventions that alter the eye's refractive power. Assessing myopia progression under preventive measures requires consideration of age-dependent physiological changes in axial length. Standardized comparison parameters, such as the cumulative absolute reduction in axial elongation (CARE) can facilitate the objective evaluation of the efficacy of the intervention. Regular monitoring of refraction and axial length should also be performed in young adults with risk factors, as myopia onset and progression can occur even at this age.

Near binocular visual function in young adult orthokeratology versus soft contact lens wearers.

Effects of orthokeratology lens on axial length elongation in unilateral myopia and bilateral myopia with anisometropia children

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.

AimsTo determine if ‘Defocus Incorporated Soft Contact’ (DISC) lens wear slows childhood myopia progression.MethodsA 2-year double-blind randomised controlled trial was carried out in 221 children aged 8–13 years, with myopia...

BackgroundTo 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).MethodsA 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.ResultsThe 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.ConclusionsOverall, 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.

The association study between MTOR and high myopia in a Han Chinese population