Stability of peripheral refraction changes in orthokeratology for myopia

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.

One-year results for myopia control with aspheric base curve orthokeratology lenses: A prospective randomised clinical trial

PURPOSE

To compare the effect of orthokeratology (ortho-k) using aspheric or spherical base curve (BCA vs. BCS) contact lenses on axial elongation and the relative peripheral refraction change (RPRC) in Chinese children.

METHODS

Children aged 8-12 years with myopia between -0.75 and -4.00 D and astigmatism ≤1.00 D were randomly assigned to the BCA or BCS group. Peripheral refraction was assessed at 10°, 20° and 30° along the temporal and nasal retina at baseline and at the 12-month visit. Axial length (AL) was measured under cycloplegia at baseline and at the 6- and 12-month visits. Only right eye data were analysed. Repeated-measures analysis of covariance was performed to examine the differences in axial elongation and the RPRC between the BCA and BCS groups.

RESULTS

The 1-year results from 31 BCA and 32 BCS subjects were analysed. No significant between-group differences were found at baseline (p ≥ 0.28). At the 12-month visit, the BCA lens produced a greater absolute RPRC along the horizontal meridian than the BCS lens (p < 0.001). Axial elongation was slower in the BCA group (0.19 ± 0.20 mm) than in the BCS group (0.29 ± 0.14 mm; p = 0.03). Axial elongation was correlated with the RPRC at 10° (r = 0.43, p = 0.02) and 20° (r = 0.39, p = 0.03) along the temporal retina in the BCA group; however, these correlations were not observed in the BCS group.

CONCLUSION

The BCA ortho-k lens could improve the efficacy of slowing axial elongation in children. The improved myopia control observed in the BCA group may be the result of a larger myopic shift in relative peripheral refraction within 20° along the temporal retina.

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.

Long-term variations and influential factors of the treatment zone of wearing orthokeratology lenses

PURPOSE

To investigate the variation trend of the treatment zone (TZ) during 12 months of Orthokeratology (Ortho-K) from the perspective of the treatment zone size (TZS), decentration (TZD) and the weighted Zernike defocus coefficient of the treatment zone (Cweighteddefocus).

METHODS

94 patients were included in this retrospective study, who were fitted with a 5-curve vision shaping treatment (VST) lens (n = 44) or a 3-zone corneal refractive therapy (CRT) lens (n = 50). The TZS, TZD and Cweighteddefocus up to 12 months were analyzed.

RESULTS

TZS (F(4,372) = 10.167, P＜0.001), TZD (F(4,372) = 8.083, P＜0.001) and Cweighteddefocus (F(4,372) = 7.100, P＜0.001) were significantly increased with time during overnight Ortho-K treatment. The TZS increased sharply from 1 week to 1 month of overnight Ortho-K (F = 25.479, P <.001) and stayed smooth then. It showed growing tendency from 6 to 12 months (F = 8.407, P =.005). The TZD (F = 16.637, P <.001) and Cweighteddefocus (F = 13.401, P <.001) increased significantly until 1 month and kept stable until 12 months (all P＞0.05). The univariant linear regression analysis showed that TZS of the last visit was correlated with baseline myopia (β = 0.219, P =.034). Also, the greater final Cweighteddefocus was correlated with higher baseline myopia (β = -0.589, P＜0.001) and higher corneal astigmatism (β = -0.228, P =.007) at the onset of lens wear with the multiple linear regression.

CONCLUSION

The TZS, TZD and Cweighteddefocus kept stable after 1 month of Ortho-K while the TZS had an increasing trend after 6 months. Children with higher myopic eyes or higher corneal astigmatism at baseline tended to have smaller TZS and greater Cweighteddefocus at 12 months.

Changes in relative peripheral refraction in children who switched from single-vision lenses to Defocus Incorporated Multiple Segments lenses

PURPOSE

To investigate changes in relative peripheral refraction (RPR) associated with myopia progression in children who wore single-vision (SV) lenses for 2 years and switched to Defocus Incorporated Multiple Segments (DIMS) lenses in the third year versus children who wore DIMS lenses for 3 years.

METHODS

In the first 2 years, children were allocated randomly to wear either DIMS or SV lenses. In the third year, children in the DIMS group continued to wear these lenses, while those in the SV group were switched to DIMS lenses (Control-to-DIMS group). Central and peripheral refraction and axial length were monitored every 6 months.

RESULTS

Over 3 years, the DIMS group (n = 65) showed good myopia control and maintained a relatively constant and symmetrical RPR profile without significant changes. In the first 2 years, children who wore SV lenses (n = 55) showed asymmetrical RPR changes, with significant increases in hyperopic RPR at 20° nasal (N) (mean difference: 0.88 ± 1.06 D, p < 0.0001) and 30N (mean difference: 1.07 ± 1.09 D, p < 0.0001). The Control-to-DIMS group showed significant myopia retardation after wearing DIMS lenses in the third year. When compared with the RPR changes in the first 2 years, significant reductions in hyperopic RPR were observed at 20N (mean difference: -1.14 ± 1.93 D, p < 0.0001) and 30N (mean difference: -1.07 ± 1.17 D, p < 0.0001) in the third year. However, no significant difference between the RPR changes found in the nasal retina and temporal retina (p > 0.05) was noted in the third year.

CONCLUSION

Symmetrical changes in RPR were found in children switching from SV to DIMS lenses, and a symmetrical pattern of RPR was noted in children who wore DIMS for 3 years. Myopia control using myopic defocus in the mid-periphery influenced the RPR changes and retarded myopia progression by altering the eye's growth pattern.

Peripheral refraction, relative peripheral refraction, and axial growth: 18-month data from the randomised study-Clinical study Of Near-sightedness; TReatment with Orthokeratology Lenses (CONTROL study)

PURPOSE

To investigate changes in peripheral and relative peripheral refraction (RPR) during orthokeratology lens (OKL) use in children, and predictors for myopia progression in a randomized controlled trial.

METHODS

Refraction and axial length (AL) were measured at baseline, 6, 12, and 18 months for children aged 6-12 years, with myopia of 0.5 to 4.75 dioptres (D) spherical component randomized to either OKL or single-vision spectacles (SVS) at baseline. Cycloplegic spherical equivalent refractive error (SEQ) was measured on-axis and eccentric at 10°, 20°, and 30° during nasal and temporal gaze in the horizontal plane with Shin-Nippon Nvision-K 5001. RPR was computed as SEQ_{(eccentricity)} minus SEQ_{(on axis)} . AL was measured with Lenstar LS900.

RESULTS

Twenty-one and 28 subjects from the OKL and SVS groups, respectively were available for analysis. OKL wear induced significant myopic RPR at all eccentricities (p ≤ 0.004) whereas peripheral refraction only changed in two out of six eccentric measuring points. Baseline peripheral refraction SEQ at all eccentricities, baseline on-axis SEQ, and baseline RPR at 30° nasal eccentricity were positively correlated to treatment efficacy defined as change in AL.

CONCLUSION

We found no correlations between change in RPR and treatment efficacy defined as change in AL. Interestingly, our results suggest that the central emmetropisation that occurs during OKL-use accounts for most of the optical changes and to a lesser extent the mid-peripheral plus-zone of the lens.

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

PURPOSE

To 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).

METHODS

Children 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.

RESULTS

After 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.

CONCLUSIONS

Ortho-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.

One-year analysis of the refractive stability, axial elongation and related factors in a high myopia population after Implantable Collamer Lens implantation

PURPOSE

To investigate the refractive stability, axial length (AL) changes and their related factors in a high myopia population after Implantable Collamer Lens (ICL) implantation.

METHODS

This prospective study included 116 eyes of 116 patients divided into several groups based on the spherical equivalent refractive error (SE)-SE > - 6 D, - 12 ≤ SE < - 6 D and SE < - 12 D groups-and AL-AL < 28 mm and AL ≥ 28 mm groups. The uncorrected and corrected distance visual acuity, refraction, AL and intraocular pressure were followed for 1 year.

RESULTS

SE changed from - 11.53 ± 5.25 D preoperatively to - 0.33 ± 0.70 D at 1 week, and further changed to - 0.48 ± 0.77 D at 1 year after ICL implantation, with average progression being - 0.15 ± 0.37 D from 1 week to 1 year after surgery. AL changed from 27.95 ± 2.33 mm preoperatively to 27.98 ± 2.36 mm 1 year after surgery, with an average axial elongation of 0.03 ± 0.12 mm. The mean axial elongation rate was 0.05 mm/year in the SE < - 12 D group, being significantly faster than the other refractive groups (P < 0.05); it was 0.06 mm/year in the AL ≥ 28 mm group, being significantly faster than the AL < 28 mm group (P < 0.05).

CONCLUSION

Patients with high myopia and long AL showed a continuous myopic progression and axial elongation at an adult age one year after ICL surgery, especially in those with myopia higher than - 12.00 D and AL longer than 28.00 mm.

Comparison of peripheral refraction and higher-order aberrations between orthokeratology and multifocal soft contact lens designed with highly addition

Purpose

To compare peripheral defocus, higher-order aberrations (HOAs), and contrast visual acuity (CVA) in myopic children wearing orthokeratology (OK) lenses and multifocal soft contact lenses (MSCLs) designed with highly addition.

Methods

This is a prospective, nonrandomized, controlled study. Subjects at 8 to 13 years of age with spherical equivalent refraction from − 1.00 to − 5.00 dioptres (D) were included in the OK group (n = 30) and MSCL group (n = 23). Relative peripheral corneal defocus (RPCD) and relative peripheral refraction (RPR) were measured before and after wearing lenses. HOAs including spherical aberration (SA), coma, trefoil, and total HOAs, and high (100%) and low (10%) CVA were compared between the groups. Axial length (AL) was measured before and after wearing the lenses for 1 year.

Results

After wearing the lenses, subjects in the MSCL group had RPCD and RPR values similar to the OK group at the paracentral (within 2 mm of the cornea or 20° of the retina, all p > 0.05) but larger than the OK group at the periphery (all p < 0.05). All HOAs increased after wearing the lenses except the trefoil in the MSCL group (all p < 0.05). HOAs increased more in the OK group (all p < 0.05). The 100% and 10% CVAs were worse in the MSCL group (p = 0.02 and p = 0.004). After 1 year, AL elongation was 0.37 mm (SD = 0.16) in the MSCL group and 0.28 mm (0.16) in the OK group (p = 0.06).

Conclusion

MSCL produced larger myopic defocus at the periphery, increased less HOAs and had worse CVA than OK lens. The high addition of this MSCL did not result in better myopia control efficacy

Trial registration

Chinese Clinical Trial Registry: ChiCTR1800018564. Registered 25 September 2018; retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=31376

Nasal-temporal asymmetric changes in retinal peripheral refractive error in myopic adolescents induced by overnight orthokeratology lenses

Objective

To observe the changes in peripheral refraction in myopic adolescents after overnight orthokeratology and its influencing factors.

Methods

This was a prospective study among young myopic adolescents aged 8-14 years (n = 21). The peripheral refraction of the subjects was measured at 5, 10, 15, 20, 25, and 30° from the nasal and temporal side to the central fixation by WAM-5500 Open-field refractometer. The axial length, baseline spherical equivalent refraction, and other parameters were measured. The data were measured at baseline and 1, 3, and 12 months after wearing orthokeratology lenses.

Results

The relative peripheral refraction at the nasal and temporal side from central to 30° eccentricity revealed relative hyperopic defocus in all subjects at baseline measurement. One month after wearing the orthokeratology lenses, the relative peripheral refraction changed to myopic defocus, the nasal-temporal relative peripheral refraction was asymmetric, and the observed difference was statistically significant. Positive correlations were found between the change amount of nasal relative peripheral refraction and baseline spherical equivalent refraction, the baseline nasal relative peripheral refraction was higher than that on the temporal side, and after orthokeratology, the value of nasal relative peripheral refraction was lower than that on the temporal side. The changes at 30° on both sides were correlated to the axial elongation (r_Nasal = 0.565, r_Temporal = 0.526, p < 0.05).

Conclusion

This study demonstrated that after orthokeratology, relative peripheral hyperopia in the myopic patients turned into relative peripheral myopia, and the nasal-temporal asymmetry changed significantly after orthokeratology, which was correlated with the baseline refractive state.

Alterations in peripheral refraction with spectacles, soft contact lenses and orthokeratology during near viewing: implications for myopia control

CLINICAL RELEVANCE

The peripheral refraction profile in myopes with different corrective modalities varies significantly for both distance and near viewing and will have implications in managing myopia.

BACKGROUND

This study investigated how the magnitude of peripheral myopic defocus induced by Ortho-K varies with and without accommodation, and how this compares to single vision spectacles and soft-contact-lenses (SCL).

METHODS

Relative peripheral refraction (RPR) of 18 young adults (spherical equivalent -1.00 D to -4.50 D) was determined along the horizontal meridian (±10°, ±20°, ±25°) during distance (3-metres) and near viewing (0.2-metres), and along vertical meridian (±10°, ±15°) for distance viewing alone. Measurements were obtained in an uncorrected state and with single vision spectacles, soft contact lens and Ortho-K. Changes in RPR and astigmatic components were compared between distance and near viewing with all different modalities.

RESULTS

A significant interaction (p = 0.02) between relative peripheral refraction and the target distance (distance and near viewing) was found among different refractive modalities. Single overnight Ortho-K lens wear alone led to relative peripheral myopia for both distance (mean RPR ± SE: -0.92 ± 0.21D and -1.04 ± 0.22D) and near viewing (-0.71 ± 0.17D and -0.76 ± 0.20D). Comparisons of relative peripheral refraction between different corrective modalities at each eccentricity indicated statistical significance of RPR at extreme locations along both temporal and nasal meridian (±20 and ±25°, p < 0.05). RPR with soft contact lenses and spectacles were similar for both distance and near viewing (p > 0.05).

CONCLUSION

Single overnight Ortho-K lens wear alone shifted the RPR in the myopic direction for both distance and near viewing in comparison with single vision spectacles and soft contact lenses. The Ortho-K lens designs that offer a large amount of mid-peripheral corneal steeping, in-turn leading to high relative peripheral myopia for both distance and near viewing and might offer beneficial effects on myopia control.

Efficacy and safety of atropine to control myopia progression: a systematic review and meta-analysis

Background

The effect and safety of atropine on delaying the progression of myopia has been extensively studied, but its optimal dose is still unclear. Therefore, the purpose of this meta-analysis is to systematically evaluate the safety and effectiveness of atropine in controlling the progression of myopia, and to explore the relationship between the dose of atropine and the effectiveness of controlling the progression of myopia.

Methods

This work was done through the data searched from PubMed, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. The Cochrane Handbook was also used to evaluate the quality of the included studies. In addition, a meta-analysis was performed using Revman5.3 software.

Results

A total of 10 randomized controlled trials (RCTs) were included. Myopia progression was mitigated greater in the atropine treatment group than that in the control group, with MD = − 0.80, 95% CI (− 0.94, − 0.66) during the whole observation period. There was a statistical difference among 0.05, 0.5, and 1.0% atropine (P = 0.004). In addition, less axial elongation was shown, with MD = − 0.26, 95% CI (− 0.33, − 0.18) during the whole observation period.

Conclusion

The effectiveness of atropine in controlling the progression of myopia was dose related. A 0.05% atropine was likely to be the optimal dose.