Update on Orthokeratology in Managing Progressive Myopia in Children: Efficacy, Mechanisms, and Concerns

Comparison of three VST orthokeratology lenses in axial length growth and average corneal reshaping in myopia children: A retrospective self-controlled study

Purpose

To determine the differences in myopia control efficiency and corneal reshaping between three different brands of orthokeratology (OK) lenses (Lucid, Euclid, and Alpha).

Method

We retrospectively reviewed subjects who started simultaneously using different brands of OK lenses. For each participant, every 6 months in the 19 months of following, the changes in axial length (AL), horizontal and vertical maximum distances of the treatment zone (HMDTZ and VMDTZ), width of the high convex zone (WHCZ), distance of decentration, and horizontal and vertical components of the decentration vector were measured. The average values of the above data, the average value of the decentration vector (ADV), and the average value of decentration calculated algebraically (ADA) were calculated.

Results

All the three pairs (Lucid (n = 46) vs. Euclid (n = 46): groups Lucid-versus-Euclid-Lucid (LE-L) and LE-E), Lucid (n = 50) vs. Alpha (n = 50): groups LA-L and LA-A), and Euclid (n = 17) vs. Alpha (n = 17): groups EA-E and EA-A) showed good comparability. Regarding the change in AL during 19 months, none of the pairs showed significant differences (LE-L:0.27 ± 0.24 mm, LE-E:0.31 ± 0.24 mm (p = 0.68); LA-L:0.36 ± 0.26 mm, LA-A:0.36 ± 0.27 mm (p = 0.85); EA-E:0.34 ± 0.27 mm, EA-A:0.41 ± 0.28 mm (p = 0.63)). Regarding treatment zone, Lucid showed the largest HMDTZ and VMDTZ (both p < 0.05). Regarding the WHCZ, none of the pairs showed significant differences. For the ADV and ADA, Lucid had more ADV and ADA than Euclid (ADV: LE-L:0.73 ± 0.44 mm, LE-E:0.55 ± 0.45 mm, p < 0.05; ADA: LE-L:0.80 ± 0.41 mm, LE-E:0.63 ± 0.44 mm, p < 0.05), and the remaining pairs showed no significant difference. For the overall cohort with 113 eyes, the change in AL was weakly correlated with both ADV and ADA (both p < 0.05). Regarding the ADV/ADA, all pairs showed no significant differences, indicating equal lens position stability.

Conclusion

After OK, there were no significant differences between the different pairs of the three brands in AL growth, WHCZ, or lens position stability, although Lucid had a larger treatment zone than Euclid and Alpha, and Lucid had more decentration than Euclid. A larger lens decentration were weakly related to less AL growth.

Changes in axial length in anisometropic children wearing orthokeratology lenses

Purpose

There is a particular anisometropia occurring in one eye with myopia, while the other eye has very low myopia, emmetropia, or very low hyperopia. It is unclear how the binocular axial length changes when these children wear unilateral OK lenses only in the more myopic eyes. This study investigates the changes in the axial elongation of both eyes.

Methods

This is a 1-year retrospective study. In total, 148 children with myopic anisometropia were included. The more myopic eyes were wearing orthokeratology lenses (treated eyes), whereas the contralateral eyes were not indicated for visual correction (untreated eyes). The untreated eyes were classified into three subgroups based on the spherical equivalent refraction (SER): low myopia (≤ -0.50 D, n = 37), emmetropia (+0.49 to -0.49 D, n = 76), and low hyperopia (≥0.50 D, n = 35). Changes in the axial length (AL) were compared between the untreated and treated eyes and among the three subgroups.

Results

The axial elongation was 0.14 ± 0.18 mm and 0.39 ± 0.27 mm in all treated and untreated eyes, respectively (p < 0.001). The interocular AL difference decreased significantly from 1.09 ± 0.45 mm at the baseline to 0.84 ± 0.52 mm at 1 year (p < 0.001). The baseline median (Q1, Q3) SER of the untreated eyes were -0.75 D (-0.56, -0.88 D), 0.00 D (0.00, -0.25 D), and +0.75 D (+1.00, +0.62 D) in low myopia, emmetropia, and low hyperopia subgroups, respectively. The axial elongation was 0.14 ± 0.18 mm, 0.15 ± 0.17 mm, and 0.13 ± 0.21 mm (p = 0.92) in the treated eyes and 0.44 ± 0.25 mm, 0.35 ± 0.24 mm, and 0.41 ± 0.33 mm in the untreated eyes (p = 0.11) after 1 year. Multivariate linear regression analyses only showed significant differences in axial elongation between the emmetropia and low myopia subgroups of untreated eyes (p = 0.04; p > 0.05 between other subgroups).

Conclusion

Unilateral orthokeratology lenses effectively reduced axial elongation in the more myopic eyes and reduced interocular AL differences in children with myopic anisometropia. The refractive state of the untreated eyes did not affect the axial elongation of the more myopic eye wearing the orthokeratology lens. In the untreated eyes, AL increased faster in the low myopia subgroup than in the emmetropia subgroup.

The rate of orthokeratology lens use and associated factors in 33,280 children and adolescents with myopia: a cross-sectional study from Shanghai

OBJECTIVES

To investigate the rate of orthokeratology lens (ortho-k lens) use and its associated factors in children and adolescents with myopia.

METHODS

Cross-sectional study. Children from 104 primary and middle schools in Shanghai were enrolled by cluster sampling. Ophthalmic examinations were conducted and information was obtained using questionnaires for associated factors analysis.

RESULTS

A total of 72,920 children and adolescents were included, among which 32,259 were the potential population for ortho-k lens use. A total of 1021 participants used ortho-k lenses, equating to a use rate of 1.4% in the total population and 3.1% in the potential population. Age (OR 0.91, 95% CI: 0.88-0.95, p < 0.001), BMI (≥95th percentile: OR 0.48, 95% CI: 0.35-0.66, p < 0.001), age at initiation of refractive correction (≤12 years: OR 1.75, 95% CI: 1.31-2.33, p < 0.001), and parental myopia (either: OR 2.09, 95% CI: 1.58-2.75, p < 0.001; both: OR 3.94, 95% CI: 3.04-5.11, p < 0.001) were independently associated with ortho-k lens use. Of the ortho-k lenses users, 12.4% had a logMAR CVA of ≥0.3. A correction target (SE) of ≤-3.0 D (OR 2.05, 95% CI: 1.38-3.05, p < 0.001) and a sleeping duration of ≤6 h (OR 4.19, 95% CI: 2.03-8.64, p < 0.001) were factors independently associated with CVA ≥ 0.3.

CONCLUSIONS

A certain proportion of children and adolescents in Shanghai chose to wear ortho-k lenses, related to the situation of parents and children themselves. Health education and follow-ups should be strengthened to ensure orthokeratology application quality.

Long-Term Efficacy of Orthokeratology to Control Myopia Progression

OBJECTIVES

To assess the efficacy of orthokeratology in controlling the rate of myopia progression in children and investigate the factors associated with axial length (AL) growth rate with an average of 48 months of orthokeratology lens wear.

METHODS

As a retrospective study, 84 subjects underwent relatively complete ophthalmologic examinations. After initial lens wear, AL was measured on average every 12 months. The linear mixed-effects model (LMM) was used to compare the differences in AL growth rates at each time interval. The contribution of the independent variables to AL change was assessed using multiple linear regression.

RESULTS

In the LMM, there was a significant difference in the AL growth rate ( P <0.001) at each follow-up. The growth rate of AL was associated with initial AL, spherical equivalent refractive errors (SERs) and diameter of lens ( P =0.045, 0.003 and 0.037, respectively). When the baseline age was included as a factor, the influence of initial AL and SER became insignificant in the analysis, whereas age and diameter of lens were significantly correlated with the growth rate of AL ( P< 0.001 and P< 0.001, respectively). There were significant differences in growth rates among different age groups.

CONCLUSIONS

Results of the study demonstrated that the factors associated with lower growth rate in AL were older age and longer diameter of lens.

Axial length shortening after orthokeratology and its relationship with myopic control

Purpose

To determine the pattern of axial variation in subjects with initial shortened axial length during the entire period of orthokeratology and to discuss the possibility of shortened AL after one month of orthokeratology becoming a predictor of myopia control.

Method

This study retrospectively included 106 children with myopia aged 8 to 14 wearing OK lenses. Fifty-four eyes with shortened axial length (AL) at the first-month visit were enrolled in the axial length shortening (ALS) group, and fifty-two eyes without shortened AL were enrolled in the no axial length shortening (NALS) group. Axial length and refractive error at baseline and within the entire period of orthokeratology (20 months), including fitting, washout period and re-wear, were measured. Eighty-five children who started wearing single vision spectacle were also included as a control group.

Results

In the ALS group, AL became longer after shortening and slowly exceeded baseline; afterward, AL experienced a rebound during the washout period and shortened again if OK lenses were re-worn. After washout period, significant difference in AL (ALS:0.28 ± 0.19 mm, NALS: 0.52 ± 0.17 mm) and spherical equivalent (ALS:-0.43 ± 0.44D, NALS:-0.91 ± 0.40D) between the two groups were found(P<0.05). The changes in AL and SE were both significantly correlated with the changes in AL at the first-month visit (P<0.05).

Conclusion

After AL is shortened in the initial stage of orthokeratology, it will experience a rapid rebound during the washout period, and the shortening can reappear when re-wearing OK lenses. Hence, the evaluation of orthokeratology will be more objective and accurate after the wash-out period. In addition, the existence and degree of axial shortening can be used as a predictor of long-term myopia development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02461-4.

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

Efficacy of Myopia Control and Distribution of Corneal Epithelial Thickness in Children Treated with Orthokeratology Assessed Using Optical Coherence Tomography

The association between myopia control efficacy in children treated with orthokeratology and corneal epithelial thickness is still unknown. The aim of this study was to explore the corneal epithelial thickness and its association with axial length changes in children treated with orthokeratology. This retrospective cohort study enrolled children aged from 9 to 15 years who had received orthokeratology for myopia control and had been followed up for at least 1 year. Anterior segment optical coherence tomography was performed to generate wide epithelial thickness maps of the patients. Annual axial length changes were calculated from the axial length at 6 months after the initiation of orthokeratology lens wear and at final measurements. Corneal epithelial thickness data were obtained from 24 sectors and a central 2 mm zone of the wide epithelial thickness map. Associations between annual axial length changes and corneal epithelial thickness for each sector/zone of the wide epithelial thickness map, and orthokeratology treatment data were determined by generalized estimating equations. Finally, a total of 83 eyes of 43 patients (mean age 11.2 years) were included in the analysis. The mean annual axial length change was 0.169 mm; when regressing demographic and ortho-k parameters to mean annual axial length changes, age and target power were both negatively associated with them (β = −14.43, p = 0.008; β = −0.26, p = 0.008, respectively). After adjusting for age and target power, the annual axial length changes were positively associated with the corneal epithelium thickness of IT1, I1, SN2, and S2 sectors of the wide epithelial thickness map, and negatively with that of the I3 sector. In conclusion, we identified associations between annual axial length changes and the corneal epithelium thickness of certain sectors in children treated with orthokeratology. This may facilitate the design of orthokeratology lenses with enhanced efficacy for myopia control.

Changes in corneal densitometry after long-term orthokeratology for myopia and short-term discontinuation

Purpose

To quantify changes in corneal densitometry after long-term orthokeratology treatment in myopic children and to analyze the reversibility one month after discontinuation.

Methods

Seventy-four myopic subjects aged 8–16 years, who wore orthokeratology lenses for two years, were divided into relatively steep- (lens movement within 1.0–1.5 mm, thirty-six participants) and flat-fitting groups (lens movement within 1.5–2.0 mm, thirty-eight participants). Based on refractive errors, they were divided into low and moderate myopia groups (thirty-seven participants in each group). Corneal densitometry was performed using Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) at each follow-up timepoint. Repeated-measures analysis of variance was used to compare the parameters before and after orthokeratology.

Results

The corneal densitometry values over the 0–10 mm diameter area increased from 12.84±1.38 grayscale units (GSU) at baseline to 13.59±1.42 GSU after three-month orthokeratology (P = .001) and reached 14.92±1.45 GSU at two years (P < .001). An increase in densitometry began at one month (P = .001) over the 0–2 mm annulus compared with that at three months over the 2–6 mm and 6–10 mm zones (P = .002,.014). The densitometry values significantly increased at three months in the relatively steep-fitting group (P = .003) and at one year in the relatively flat-fitting group (P = .001). After discontinuation of orthokeratology for one month, the values showed no significant decrease.

Conclusions

Long-term orthokeratology treatment causes a small but statistically significant increase in corneal densitometry values. During the first year, the onset of these changes was related to the fitting mode. Corneal densitometry values showed no significant reduction after one-month discontinuation.

Bacterial keratitis: identifying the areas of clinical uncertainty

Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.

A new approach for quantifying epithelial and stromal thickness changes after orthokeratology contact lens wear

The aim of the study was to develop an automatic segmentation approach to optical coherence tomography (OCT) images and to investigate the changes in epithelial and stromal thickness profile and radius of curvature after the use of orthokeratology (Ortho-K) contact lenses. A total of 45 right eyes from 52 participants were monitored before, and after one month of, uninterrupted overnight Ortho-K lens wear. The tomography of their right eyes was obtained using optical OCT and rotating Scheimpflug imaging (OCULUS Pentacam). A custom-built MATLAB code for automatic segmentation of corneal OCT images was created and used to assess changes in epithelial thickness, stromal thickness, corneal and stromal profiles and radii of curvature before, and after one month of, uninterrupted overnight wear of Ortho-K lenses. In the central area (0-2 mm diameter), the epithelium thinned by 12.8 ± 6.0 µm (23.8% on average, p < 0.01) after one month of Ortho-K lens wear. In the paracentral area (2-5 mm diameter), the epithelium thinned nasally and temporally (by 2.4 ± 5.9 µm, 4.5% on average, p = 0.031). The stroma thickness increased in the central area (by 4.8 ± 16.1 µm, p = 0.005). The radius of curvature of the central corneal anterior surface increased by 0.24 ± 0.26 mm (3.1%, p < 0.01) along the horizontal meridian and by 0.34 ± 0.18 mm (4.2%, p < 0.01) along the vertical meridian. There were no significant changes in the anterior and posterior stromal radius of curvature. This study introduced a new method to automatically detect the anterior corneal surface, the epithelial posterior surface and the posterior corneal surface in OCT scans. Overnight wear of Ortho-K lenses caused thinning of the central corneal epithelium. The anterior corneal surface became flattered while the anterior and posterior surfaces of the stroma did not undergo significant changes. The results are consistent with the changes reported in previous studies. The reduction in myopic refractive error caused by Ortho-K lens wear was mainly due to changes in corneal epithelium thickness profile.

Time Course of Perceived Visual Distortion and Axial Length Growth in Myopic Children Undergoing Orthokeratology

Purpose: To establish the time course of the subjective visual function changes during the first month of orthokeratology treatment in myopic children, and to investigate how the time course variations are associated with the objective optical quality changes and the axial length growth (ALG) after 1 year of treatment.

Methods: A total of 58 myopic children aged from 8 to 16 years participated in this self-controlled prospective study. All subjects were fitted with designed spherical four-zone orthokeratology lenses. Subjective visual function was evaluated with orientation discrimination threshold (ODT), and objective optical quality was quantified with the high-order aberration root-mean-square (HOA-RMS) and the changing speed of HOA. The measurements were done before the lens fitting and 1 day, 1-, 2-, and 4-weeks after lens wear. Axial length was obtained at baseline and 1-year follow-up, and ALG was defined as the difference. One-way ANOVA was conducted to compare the difference for statistical analysis.

Results: After lens fitting, the ODT time courses peaked on day 1 in 28 children, 1 week in 15 children, 2 weeks in 11 children, and 4 weeks in 4 children. In contrast, the HOA-RMS steadily rose during the first month, and the changing speed of HOA was only transiently elevated on day 1 after the initial lens wear. The ALG was 0.12 ± 0.20 mm in subjects whose ODT peaked at day 1, 0.08 ± 0.09 mm in subjects whose ODT peaked on 1-week, and 0.12 ± 0.15 mm in subjects whose ODT peaked on 2-week or later. There was no difference in axial growth among the subjects whose ODT peaked at different days (P = 0.734).

Conclusion: While half ODT time course resembled the changing speed of HOA with a transient elevation on day 1, about a quarter of the ODT time course resemble the steadily rising of HOA-RMS, and the rest was located in the middle. The ALGs in children with different types of ODT time courses were similar.

The treatment zone size and its decentration influence axial elongation in children with orthokeratology treatment

BACKGROUND

To investigate whether the treatment zone size (TZS) and treatment zone decentration (TZD) will affect the axial elongation in myopic children undergoing orthokeratology treatment.

METHODS

A self-controlled retrospective study was conducted on 352 children who met the inclusion criteria. Axial length was measured before and at 12 months after the initial lens wear. Corneal topography was measured at baseline and at each follow-up after lens wear. The Corneal topography obtained from the 12-month visit was used to quantify TZS and TZD for each subject. Cycloplegic refraction was required for all children before fitting the orthokeratology lenses.

RESULTS

Axial elongation was significantly associated with age, baseline spherical equivalent (SE), TZS, and TZD with univariate linear regression. In groups with both small and large TZS, axial elongation was significantly decreased with large TZD (both P < 0.01). In groups with both small and large TZD, axial elongation was significantly decreased with small TZS (P = 0.03 for small TZD, P = 0.01 for large TZD). Age, SE, and TZD were significantly associated with axial elongation in multiple regression (all P < 0.01).

CONCLUSION

Relatively smaller TZS and larger TZD may be beneficial in slowing myopia progression in children with orthokeratology treatment.

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.

Results with Posterior Scleral Reinforcement for Progressive Highly Myopic Children in Hungary

PURPOSE

We have been performing posterior scleral reinforcement in our ophthalmological department since 1992 on progressive highly myopic eyes. Here, we report on our results with this technique in the foregoing 7 years in a retrospective comparative design.

METHODS

Thirty-eight eyes of 32 patients, operated according to Snyder-Thompson's method, were enrolled in this study, and a control group of 9 age- and myopia-matched children's 14 eyes was built for comparison. Pre- and postoperative best-corrected visual acuity, subjective refractive error (spherical equivalent of spectacle dioptres), and axial length were recorded. Changes within groups were calculated, as well as baseline parameters and their changes during follow-up, and compared between the groups. Correlation analysis was performed to identify factors that could influence myopia progression.

RESULTS

Myopic progression was significantly lower in the operated than in the nonoperated group, both in terms of mean annual axial length as well as refractive error changes (0.21 ± 0.08 mm versus 0.49 ± 0.19 mm and 0.18 ± 0.29 D versus 0.6 ± 0.33 D, respectively). Mean overall visual improvement was more explicit in operated eyes as compared to those left untreated (0.15 ± 0.09 versus 0.01 ± 0.1). No association of any factor with myopia progression could be identified. We encountered no serious or lasting complications.

CONCLUSION

In our clinical practice, posterior scleral reinforcement according to Snyder-Thompson proved to be a safely applicable and effective surgical method to stop or significantly retard pathological increases in axial length and dioptres, and thus can help prevent the onset of myopic degenerative lesions, and irreversible visual impairment in the long run.

Effect of 0.01% atropine eye drops on choroidal thickness in myopic children

PURPOSE

To examine the effects of low-dose atropine on the choroidal thickness (CT) of young children in Shanghai, China, as well as the ocular biometrics of myopic patients.

METHODS

A total of 59 eyes of 35 myopic children had subfoveal CT and ocular biometry measurements taken before and after 2weeks, 4weeks, and 8weeks of treatment with 0.01% atropine. All eyes were measured using swept-source optical coherence tomography. CT and changes in it were also recorded.

RESULTS

The choroid exhibited significant and continuous thickening under the fovea after patients were treated with 0.01% atropine. The magnitude of change in CT varied with the location and with the duration of treatment. The greatest change was observed in the fovea. There was no significant relationship between changes in subfoveal CT and axial length.

CONCLUSIONS

Using 0.01% atropine eye drops significantly increased CT in eyes of young myopic children, by variable magnitude depending upon location.

Highlights from the 2019 International Myopia Summit on 'controversies in myopia'

Myopia is an emerging public health issue with potentially significant economic and social impact, especially in East Asia. However, many uncertainties about myopia and its clinical management remain. The International Myopia Summit workgroup was convened by the Singapore Eye Research Institute, the WHO Regional Office for the Western Pacific and the International Agency for the Prevention of Blindness in 2019. The aim of this workgroup was to summarise available evidence, identify gaps or unmet needs and provide consensus on future directions for clinical research in myopia. In this review, among the many 'controversies in myopia' discussed, we highlight three main areas of consensus. First, development of interventions for the prevention of axial elongation and pathologic myopia is needed, which may require a multifaceted approach targeting the Bruch's membrane, choroid and/or sclera. Second, clinical myopia management requires co-operation between optometrists and ophthalmologists to provide patients with holistic care and a tailored approach that balances risks and benefits of treatment by using optical and pharmacological interventions. Third, current diagnostic technologies to detect myopic complications may be improved through collaboration between clinicians, researchers and industry. There is an unmet need to develop new imaging modalities for both structural and functional analyses and to establish normative databases for myopic eyes. In conclusion, the workgroup's call to action advocated for a paradigm shift towards a collaborative approach in the holistic clinical management of myopia.

Evaluating the myopia progression control efficacy of defocus incorporated multiple segments (DIMS) lenses and Apollo progressive addition spectacle lenses (PALs) in 6- to 12-year-old children: study protocol for a prospective, multicenter, randomized controlled trial

Background

Myopia is increasing in prevalence and is currently recognized as a significant public health issue worldwide, particularly in China. Once myopia develops, appropriate clinical interventions need to be prescribed to slow its progression. Currently, several publications indicate that myopic defocus (MD) retards eye growth and myopia progression. However, no clinical trials have compared the outcomes of different MD spectacle lenses in the same observational group, especially in mainland China. The aim of the present study is to compare the myopia control efficiency of two different MD spectacle lenses: defocus incorporated multiple segments (DIMS) lenses and Apollo progressive addition lenses (PALs).

Methods

The trial is designed as a 3-year, prospective, randomized, multicenter clinical trial of schoolchildren treated with DIMS lenses and PALs. A total of 600 Chinese primary school children aged 6–12 years will be recruited, and each group is intended to include 300 subjects. The inclusion criteria are myopia between − 1.00 and − 5.00 diopters and astigmatism ≤ 1.50 diopters. The follow-up time points will be 1 month (m), 3 m, 6 m, 12 m, 18 m, 24 m, 30 m, and 36 m. The primary outcome will be determined by the difference between the two groups in cycloplegic spherical equivalent refraction between baseline and the last follow-up visit. The secondary outcome is the axial length, and the exploratory outcomes include ocular biometric measures, peripheral refraction, binocular vision, accommodation, compliance, and the results of questionnaires related to wearing experiences.

Discussion

The present study will be the first randomized controlled trial in myopic primary school children treated with DIMS lenses and PALs in China. The results will indicate whether and how much different MD mechanisms retard myopia progression and axial elongation. In addition, the comparison will provide information on the clinical efficacy and safety of DIMS lenses and PALs, including information related to wearing experiences and visual function.

Trial registration

Chinese Clinical Trial Registry (ChiCTR), ChiCTR1900025645. Registered on 3 September 2019. http://www.chictr.org.cn/showproj.aspx?proj=42927.

Correlation between pigmented arc and epithelial thickness (COPE) study in orthokeratology-treated patients using OCT measurements

PURPOSE

To determine the intensity of corneal pigmented arc in orthokeratology (ortho-k)-treated children, and its correlation with key epithelial thickness measurements obtained by anterior segment optical coherence tomography (AS-OCT).

METHODS

This study is a retrospective case series. Medical records of children who received ortho-k treatment for myopia control in our hospital were reviewed. Intensity of ortho-k-associated pigmented arc and its correlation with key epithelial thickness parameters in the central 7-mm-diameter zone obtained by AS-OCT was examined. The subjects were further divided into apparent and unapparent pigmented arc groups for severity comparison.

RESULTS

The mean age of children was 11.4 years, and the incidence of corneal pigmented arc was 92.2% after lens wear for a mean duration of 21.2 months. Intensity of pigmented arc was found to be significantly correlated with key epithelial thickness parameters, including maximum and minimum epithelial thickness (Spearman's rank correlation coefficient (rs) = 0.404, P = 0.003; rs = - 0.426, P = 0.002, respectively), the difference between them (Min-Max) (rs = -0.624, P < 0.001) and standard deviation (rs = 0.659, P < 0.001). Significant correlation between intensity of pigmented arc and ortho-k target power (rs = 0.454, P = 0.001) was found. Comparison between the two groups showed significant difference in the same key epithelial thickness parameters.

CONCLUSIONS

Children receiving ortho-k treatment tended to develop pigmented arcs. Significant correlation between intensity of pigmented arc and key epithelial thickness parameters was observed. AS-OCT can be a useful tool for predicting intensity of pigmented arc in ortho-k-treated children.

Water Exposure and the Risk of Contact Lens-Related Disease

PURPOSE

To describe the association of water exposure with contact lens (CL)-related disease and explore the guidelines regarding water exposure to CL wearers, provided by CL manufacturing industry, global public health, and CL-related professional associations.

METHODS

A review of the literature was conducted by searching PubMed, MEDLINE, and Web of Science databases up to September 2017 for articles published or translated in English using keywords: contact lens* AND tap water OR swimming OR showering OR water exposure AND microbial keratitis OR Acanthamoeba keratitis OR corneal infiltrate* OR ocular adverse event*. References in all relevant publications were also reviewed.

RESULTS

Water exposure during CL wear is associated with complications ranging from sterile corneal infiltrative events to sight-threatening infections. Despite the documented risks due to water exposure, water-related habits are common among CL wearers. This suggests a lack of awareness and understanding regarding the risks among CL wearers and potentially CL practitioners. Discrepancies exist in guidelines for CL hygiene and compliance provided by the CL manufacturing industry, global public health, and CL-related professional associations. There is also widespread use of water imagery within CL marketing and packaging materials. These factors may give rise to confusion among wearers and may contribute toward risk-taking behaviors.

CONCLUSIONS

Consensus among stakeholders about water and CL care is needed. Guidelines should unequivocally advocate for the avoidance of any water exposure including handling CLs with wet hands, rinsing CLs or storage cases in tap water, showering while wearing CLs and swimming with CLs without wearing goggles.

Efficacy and safety of interventions to control myopia progression in children: an overview of systematic reviews and meta-analyses

Background

Myopia is a common visual disorder with increasing prevalence. Halting progression of myopia is critical, as high myopia can be complicated by a number of vision-compromising conditions.

Methods

Literature search was conducted in the following databases: Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica dataBASE (EMBASE), Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effects (DARE) and Centre for Reviews and Dissemination (CRD) Health Technology Assessment (HTA) database. Systematic reviews and meta-analyses investigating the efficacy and safety of multiple myopia interventions vs control conditions, were considered. Methodological quality and quality of evidence of eligible studies were assessed using the ROBIS tool and GRADE rating. The degree of overlapping of index publications in the eligible reviews was calculated with the corrected covered area (CCA).

Results

Forty-four unique primary studies contained in 18 eligible reviews and involving 6400 children were included in the analysis. CCA was estimated as 6.2% and thus considered moderate. Results demonstrated the superior efficacy of atropine eyedrops; 1% atropine vs placebo (change in refraction: -0.78D, [− 1.30 to − 0.25] in 1 year), 0.025 to 0.05% atropine vs control (change in refraction: -0.51D, [− 0.60 to − 0.41] in 1 year), 0.01% atropine vs control (change in refraction: -0.50D, [− 0.76 to − 0.24] in 1 year). Atropine was followed by orthokeratology (axial elongation: − 0.19 mm, [− 0.21 to − 0.16] in 1 year) and novel multifocal soft contact lenses (change in refraction: -0.15D, [− 0.27 to − 0.03] in 1 year). As regards adverse events, 1% atropine induced blurred near vision (odds ratio [OR] 9.47, [1.17 to 76.78]) and hypersensitivity reactions (OR 8.91, [1.04 to 76.03]).

Conclusions

Existing evidence has failed to convince doctors to uniformly embrace treatments for myopic progression control, possibly due to existence of some heterogeneity, reporting of side effects and lack of long-term follow-up. Research geared towards efficient interventions is still necessary.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1112-3) contains supplementary material, which is available to authorized users.

Microvascular complications in orthokeratology (Ortho-K): A real-time study on the microvasculature of the bulbar conjunctiva in Ortho-K treatment

Orthokeratology (Ortho-K) is an over-night hard contact lens therapy, which physically reshapes the corneal curvature in order to stabilize or temporally eliminate myopia in patients. We hypothesize that the prolonged physical contact and mechanical pressure induced by the Ortho-K lenses may create lasting inadvertent effects and damages (microangiopathy), and may bring about unwanted changes in the microvasculature of the bulbar conjunctiva. Computer-assisted intravital microscopy (CAIM) was used to view, document (via videotaping) and objectively quantify (via computer-assisted image analysis) the real-time dynamic and morphometric characteristics of the conjunctival microcirculation in long-term (at least over one year) Ortho-K patients (n = 11) and matched non-user control subjects (n = 8). Ortho-K patients were instructed to wear their lenses overnight following standard protocol. During the study, the conjunctival microcirculation of the left eye of all Ortho-K lens users was viewed, frequently re-focused and videotaped, without and with the lens in place, as outlined in Methods. The matched control subjects (non-lens wearing) were videotaped and studied in like manner. The dynamic and morphometric characteristics of each user and control subject were analyzed, quantified and summated as a severity index (SI) collectively for comparison. SI of Ortho-K lens users (4.18±1.08) differed significantly from SI of control subjects (1.75±1.39, p≤0.05). In addition, changes in the conjunctival microcirculation (e.g., flow velocity, vessel diameter, shape change, etc) were viewed and videotaped immediately after the myopic patients put on the Ortho-K lenses. Eight of the 11 Ortho-K lens users displayed significant percentage changes (p≤0.05) in flow velocity and 10 of 11 displayed significant percentage changes (p≤0.05) in vessel diameter, without and with the Ortho-K lenses. The results clearly indicated that significant microvascular changes via tissue remodeling occurred, and were caused directly by the physical presence of the Ortho-K lenses.

Comparison Between Viscous Teardrops and Saline Solution to Fill Orthokeratology Contact Lenses Before Overnight Wear

OBJECTIVE

To compare, in terms of efficacy, the differences between the use of saline solution and a viscous artificial tear to fill the lens during the first month of orthokeratology wear.

METHODS

A pilot, double-masked, crossed, randomized, and prospective study was conducted. In this study, 20 subjects (14 males and 6 females) with a mean age of 16.29±6.22 years (range, 10-26) were fitted with orthokeratology contact lenses. For the study, nonpreserved 0.9% NaCl commercial saline solution (Avizor, Madrid, Spain) and nonpreserved artificial teardrops with 0.3% of hyaluronic acid (Ocudry 0.3%; Avizor, Madrid, Spain) were used. Corneal staining, tear break up time (TBUT), topography, refraction, visual acuity, and subjective comfort and vision with the visual analog scale (score from 0 to 10, being 10 better comfort and vision) were evaluated at 1 day, 1 week, and 1 month of contact lens wear.

RESULTS

The corneal staining was statistically greater in the saline group than in the Ocudry group for the first day and during 1 week of wear (P<0.05). Comfort was found to be statistically better, with Ocudry 0.3% than saline solution, being 7.17±1.94 and 6.37±1.63, for the first day, and 8.78±0.43 and 8.15±0.62 for the day 28, respectively (P<0.05). However, no differences were found for subjective vision scores, TBUT, spherical equivalent, best-corrected visual acuity and uncorrected visual acuity, and mean keratometry between groups for any visit (P>0.05).

CONCLUSION

Viscous artificial tears improve the subjective comfort of patients and reduce the corneal staining, compared with saline solution during the orthokeratology lenses fitting process. However, no differences between solutions for the treatment efficacy, in vision and corneal topography, were found.

Accommodation function comparison following use of contact lens for orthokeratology and spectacle use in myopic children: a prospective controlled trial

AIM

To study effects of orthokeratology (Ortho-k) on accommodation function in myopic children.

METHODS

A prospective, non-randomized, case-control study was performed from September to October 2016. Eighty-three children with myopia were divided into two groups. One group was treated with the rigid contact lens for overnight Ortho-k, and the other was treated with single-vision spectacle lens (SVL). Accommodation function were assessed by accommodative amplitude (AA), accommodative sensitivity (AS), accommodative lag (Lag), negative relative accommodation (NRA), and positive relative accommodation (PRA) before and 1, 3, 6 and 12mo after treated.

RESULTS

Totally 72 myopic children were finished the follow-up: 37 in Ortho-k group and 35 in SVL group. Wearing time had a significant effect on AA, AS, Lag, and NRA of myopic children in two groups (all P<0.05). Meanwhile, there was an interaction effect between wearing time and wearing types (F_AA=5.3, F_AS=45.5, F_Lag=7.0, F_NRA=3.7, all P<0.05). However, the between-group difference of AA (F=0.1), AS (F=3.2), Lag (F=1.1), NRA (F=0.3), and PRA (F=0.1) showed no significance. AA, AS, NRA, Lag and PRA were improved significantly in Ortho-k group within 1 to 6mo after wearing.

CONCLUSION

Wearing Ortho-k can improve the accommodation function of myopic children, which might be one of the mechanisms for myopia control.

Vision Improvement and Compliance With the Use of Orthokeratology Lenses in School Children: A Sample From Five Primary Schools in Northern Taiwan

PURPOSE

To assess the visual acuity and compliance with the use of orthokeratology lenses (OrthoK) in school children.

METHODS

A retrospective study was conducted to determine the education-related factors influencing the improvement in visual acuity in myopic students using OrthoK in five primary schools in Taiwan.

RESULTS

Of the 5,173 eligible students from five primary schools, 1906 (36.8%) students were diagnosed with myopia. Among 201 (10.6%) students wearing OrthoK, 69.7% had used them for at least 1 year, 53.2% achieved visual acuity greater than 0.8 (6/7.5, log of minimal angle of resolution 0.1) in school, and 49.8% had received health education related to OrthoK care. Multiple logistic regression analysis showed that a higher possibility to achieve visual acuity greater than 0.8 was associated with more than 1-year use of OrthoK, good compliance, and receiving health education from an ophthalmologist.

CONCLUSION

It is important that children wearing OrthoK receive education and comply with the use of OrthoK for visual acuity improvement.

Early Intervention and Nonpharmacological Therapy of Myopia in Young Adults

Myopia is a condition of the eye where parallel rays focus in front of, instead of on, the retina, which results in excessive refractive power of the cornea or the lens or eyeball elongation. Studies carried out in recent years show that the etiology of myopia is complex with genetic and environmental factors playing a role. Refraction defects decrease the quality of vision, while progressing myopia can lead to partial loss of vision, which can be particularly dramatic in young adults. Therefore, it is so crucial to take appropriate actions aimed at preventing myopia progression. This is a review of nonpharmacological therapeutic possibilities of refraction defect prevention in young adults, with special regard to myofascial therapy, osteopathy, and massage of acupuncture points surrounding the eye.