Current approaches to myopia control

Myopia Control: Are We Ready for an Evidence Based Approach?

INTRODUCTION

Myopia and its vision-threatening complications present a significant public health problem. This review aims to provide an updated overview of the multitude of known and emerging interventions to control myopia, including their potential effect, safety, and costs.

METHODS

A systematic literature search of three databases was conducted. Interventions were grouped into four categories: environmental/behavioral (outdoor time, near work), pharmacological (e.g., atropine), optical interventions (spectacles and contact lenses), and novel approaches such as red-light (RLRL) therapies. Review articles and original articles on randomized controlled trials (RCT) were selected.

RESULTS

From the initial 3224 retrieved records, 18 reviews and 41 original articles reporting results from RCTs were included. While there is more evidence supporting the efficacy of low-dose atropine and certain myopia-controlling contact lenses in slowing myopia progression, the evidence about the efficacy of the newer interventions, such as spectacle lenses (e.g., defocus incorporated multiple segments and highly aspheric lenslets) is more limited. Behavioral interventions, i.e., increased outdoor time, seem effective for preventing the onset of myopia if implemented successfully in schools and homes. While environmental interventions and spectacles are regarded as generally safe, pharmacological interventions, contact lenses, and RLRL may be associated with adverse effects. All interventions, except for behavioral change, are tied to moderate to high expenditures.

CONCLUSION

Our review suggests that myopia control interventions are recommended and prescribed on the basis of accessibility and clinical practice patterns, which vary widely around the world. Clinical trials indicate short- to medium-term efficacy in reducing myopia progression for various interventions, but none have demonstrated long-term effectiveness in preventing high myopia and potential complications in adulthood. There is an unmet need for a unified consensus for strategies that balance risk and effectiveness for these methods for personalized myopia management.

Effects of online family health education on myopia prevention in children by parental myopia: a randomized clinical trial

CLINICAL RELEVANCE

Online family health education may be effective for myopia prevention in children, and the effects may be different between children with myopic and non-myopic parents.

BACKGROUND

Myopia is a common cause of vision loss. The aims of this study were to evaluate the effects of online family health education on preventing the development of myopia in children, and to estimate whether the effects vary according to parental myopia.

METHODS

A cluster randomised trial including grade 1 and grade 2 children from 12 primary schools was conducted in Guangzhou, China. Weekly online family health education messages were sent to parents in the intervention group. Data collection included eye examinations of children and questionnaires completed by parents.

RESULTS

Among the 3123 children included at baseline (1703 boys [54.5%]; mean [SD] age, 6.83 [0.73] years), 2376 completed the follow-up after 3 years. The differences in the incidence of myopia and myopic shift between the study groups were not significant in total. However, the 3-year cumulative incidence rate of myopia in the intervention group (125 of 445 [28.1%]) was significantly lower than that in the control group (225 of 603 [37.3%]; difference, 9.2% [95% CI, -14.9% to -3.5%]; P = 0.001) among children with non-myopic parents. In parallel, among children with non-myopic parents, the mean myopic change in SER was less for the intervention group than for the control group (-1.10 D vs. -1.24 D; difference, 0.13 D [95% CI, 0.03 to 0.23 D]; P = 0.01).

CONCLUSIONS

Compared with children with myopic parents, online family health education was more effective in children with non-myopic parents. The incidence of myopia and myopic shift in refraction have been reduced in children with non-myopic parents. Further studies are needed to assess these differences by parental myopia.

Efficacy of Repeated Low-Level Red Light (RLRL) therapy on myopia outcomes in children: a systematic review and meta-analysis

BACKGROUND

Myopia is the most prevalent form of refractive error that has a major negative impact on visual function and causes blurring of vision. We aimed to determine if Repeated Low-Level Red Light (RLRL) treatment is beneficial in treating childhood myopia in terms of axial length (AL), spherical equivalent refraction (SER), and sub foveal choroidal thickness (SFCT).

METHODS

This systematic review was performed on RLRL for treatment of myopia in children compared to single vision spectacles (SVS). We employed the search strategy with key terms myopia and low-level light therapy then we searched PubMed, Scopus, Cochrane, and Web of Science databases. The mean differences (MD) were used to evaluate the treatment effects. Heterogeneity was quantified using I2 statistics and explored by sensitivity analysis.

RESULTS

Five randomized controlled trials (RCTs) were included in our meta-analysis with a total of 833 patients, 407 in treatment group and 426 in control group. At a 3 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.16; 95% CI [-0.19, -0.12], SER (MD = 0.33; 95% CI [0.27, 0.38]), and SFCT (MD = 43.65; 95% CI [23.72, 45.58]). At a 6 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.21; 95% CI [-0.28, -0.15]), SER (MD = 0.46; 95% CI [0.26, 0.65]), and SFCT (MD = 25.07; 95% CI [18.18, 31.95]). At a 12 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.31; 95% CI [-0.42, -0.19]) and SER (MD = 0.63; 95% CI [0.52, 0.73]).

CONCLUSION

This is the first systematic review and meta-analysis investigating only RCTs evidence supporting the efficacy of 650 nm RLRL for myopia control in the short term of 3, 6, and 12 months follow up. The present review revealed the clinical significance of RLRL as a new alternative treatment for myopia control with good user acceptability and no documented functional or structural damage. However, the effect of long-term RLRL treatment and the rebound effect after cessation require further investigations.

Opsin 5 mediates violet light-induced early growth response-1 expression in the mouse retina

Myopia is an abnormal vision condition characterized by difficulties in seeing distant objects. Myopia has become a public health issue not only in Asian countries but also in Western countries. Previously, we found that violet light (VL, 360-400 nm wavelength) exposure effectively suppressed myopia progression in experimental chick and mice models of myopia. The inhibitory effects of VL on myopia progression are reduced in retina-specific opsin 5 (Opn5) knockout (KO) mice. Furthermore, VL exposure upregulated early growth response-1 (Egr-1) expression in the chorioretinal tissues of chicks. However, the expression of EGR-1 and role of OPN5 in mice following VL exposure remain unclear. In this study, we examined whether VL exposure-induced EGR-1 upregulation depends on Opn5 expression in the mouse retina. EGR-1 mRNA and protein expressions increased in the mouse retina and mouse retinal 661W cells following VL exposure. These increases were consistently reduced in retina specific Opn5 conditional KO mice and Opn5 KO 661W cells. Our results suggest that OPN5 mediates VL-induced EGR-1 upregulation in mice. These molecular targets could be considered for the prevention and treatment of myopia.

Ginkgo biloba extracts improve choroidal circulation leading to suppression of myopia in mice

Myopia is becoming more common across the world, necessitating the development of preventive methods. We investigated the activity of early growth response 1 (EGR-1) protein and discovered that Ginkgo biloba extracts (GBEs) activated EGR-1 in vitro. In vivo, C57BL/6 J mice were fed either normal or 0.0667% GBEs (200 mg/kg) mixed chow (n = 6 each), and myopia was induced with - 30 diopter (D) lenses from 3 to 6 weeks of age. Refraction and axial length were measured by an infrared photorefractor and an SD-OCT system, respectively. In lens-induced myopia mice, oral GBEs significantly improved refractive errors (- 9.92 ± 1.53 D vs. - 1.67 ± 3.51 D, p < 0.001) and axial elongation (0.22 ± 0.02 mm vs. 0.19 ± 0.02 mm, p < 0.05). To confirm the mechanism of GBEs in preventing myopia progression, the 3-week-old mice were divided into normally fed with either myopic-induced or non-myopic-induced groups and GBEs fed with either myopic-induced or non-myopic-induced groups (n = 10 each). Choroidal blood perfusion was measured with optical coherence tomography angiography (OCTA). In both non-myopic induced groups, compared to normal chow, oral GBEs significantly improved choroidal blood perfusion (8.48 ± 15.75%Area vs. 21.74 ± 10.54%Area, p < 0.05) and expression of Egr-1 and endothelial nitric oxide synthase (eNOS) in the choroid. In both myopic-induced groups, compared to normal chow, oral GBEs also improved choroidal blood perfusion (- 9.82 ± 9.47%Area vs. 2.29 ± 11.84%Area, p < 0.05) and was positively correlated with the change in choroidal thickness. These findings suggest that GBEs may inhibit the progression of myopia by improving choroidal blood perfusion.

Effeciency contact correction of hypermetropia in children of school-age in the distant term of caution

Objective – to study the affectiveness of contact correction of hypermetropia in school-age children in the long of observetion.Materials and methods. The study included 56 children (112 eyes) aged 6 to 16 years with hyperopic refraction and astigmatism, who used soft silicone hydrogel contact lenses to correct ametropia. In these patients, a study of visual acuity, objective and subjective clinical refraction, axial length of the eye, corneal thickness and diameter, keratometry, as well as phorometric data (accommodation, vergence, dispar areas of the oculomotor system and their interaction) in early and late observation periods. Results. When using contact correction in school-age children with hyperopia and hyperopic astigmatism, statistically significant after 3 years of observation there was an increase in uncorrected visual acuity by 85 % (t = 7.9; p <0.01), corrected visual acuity by 7 % (t = 7.4; p <0.01), keratometry in the weak meridian by 1 % (t = 6.1; p <0.01), by 1 % (t = 8.9; p <0.01) in the strong meridian, the thickness of the cornea in the central zone by 4 % (t = 4.6; p <0.01), as well as a decrease in the sphere equivalent by 38 % (t = 3,1; p <0,01), the amplitude of accommodation by 20 % (t = 5.8; p <0.01), the negative part of the relative accommodation by 20 % (t = 3.0; p <0.01), the positive part of the relative accommodation by 18 % (t = 3.5; p <0.01), excess accommodation response by 64 % (t = 7.2; p <0.01), foria by 33 % (t = 4.4; p <0.01), foria by close by 22 % (t = 2.8; p <0.01), the ratio of accommodation convergence to accommodation by 18 % (t = 3.1; p <0.01).Conclusions. As a result of 3-year observation of school-age children with hypermetropia in which correction was used by various optical methods, it was established that correction with soft silicone-hydrogel aspheric contact lenses is the most effective way to control this ametropia, which is confirmed by an increase in visual acuity, spheroequivalent indicators, as well as changes in the front surface of the cornea: an increase in thickness in the central zone, and an improvement in keratometry, as well as a positive effect on accommodation ability, muscle balance and stereoscopic vision.

Dynamics of the accommodative response and facility with dual-focus soft contact lenses for myopia control

OBJECTIVE

To assess the impact of using dual-focus soft contact lenses for myopia control on the dynamics of the accommodative response and facility.

METHODS

24 young adult myopes were fitted with dual-focus soft contact lenses for myopia control (MiSight®) and single-vision soft contact lenses (Proclear®). The WAM-5500 open-field autorefractor was used to measure the dynamics of the accommodative response (magnitude and variability) in binocular conditions, with accommodative data being gathered from the dominant eye, at three viewing distances (500 cm, 40 cm, and 20 cm) during 90 s. Also, the binocular accommodative facility was assessed with the WAM-5500 autorefractor. All participants performed the same experimental protocol with the dual-focus (MiSight) and single-vision (Proclear) soft contact lenses, with both experimental sessions being carried in two different days and following a counterbalanced order.

RESULTS

This study showed greater lags of accommodation with the MiSight than the Proclear lenses at near distances (40 cm: 1.27 ± 0.77 vs. 0.68 ± 0.37 D, corrected p-value = 0.002, Cohen-d = 0.90; and 20 cm: 1.47 ± 0.84 vs. 1.01 ± 0.52 D, corrected p-value = 0.007, Cohen-d = 0.75), whereas a higher variability of accommodation was observed with the dual-focus than the single-vision lenses at 500 cm (0.53 ± 0.11 vs. 0.23 ± 0.10 D), 40 cm (0.82 ± 0.31 vs. 0.68 ± 0.37 D), and 20 cm (1.50 ± 0.56 vs. 1.15 ± 0.39 D) (corrected p-value < 0.001 in all cases, and Cohen-ds = 0.67-2.33). Also, a worse quantitative (27.75 ± 8.79 vs. 34.29 ± 10.08 cycles per minute, p = 0.029, Cohen-d = 0.48) and qualitative (23.68 ± 7.12 vs. 28.43 ± 7.97 score, p = 0.039, Cohen-d = 0.45) performance was observed with the MiSight when compared to the Proclear lenses.

CONCLUSIONS

The use of dual-focus soft contact lenses for myopia control alters the dynamics of accommodative response and facility in the short-term. Although this optical design has demonstrated its effectiveness for myopia control, eye care specialists should be aware of the acute effects of these lenses on accommodation performance.

Scleral PERK and ATF6 as targets of myopic axial elongation of mouse eyes

Axial length is the primary determinant of eye size, and it is elongated in myopia. However, the underlying mechanism of the onset and progression of axial elongation remain unclear. Here, we show that endoplasmic reticulum (ER) stress in sclera is an essential regulator of axial elongation in myopia development through activation of both PERK and ATF6 axis followed by scleral collagen remodeling. Mice with lens-induced myopia (LIM) showed ER stress in sclera. Pharmacological interventions for ER stress could induce or inhibit myopia progression. LIM activated all IRE1, PERK and ATF6 axis, and pharmacological inhibition of both PERK and ATF6 suppressed myopia progression, which was confirmed by knocking down above two genes via CRISPR/Cas9 system. LIM dramatically changed the expression of scleral collagen genes responsible for ER stress. Furthermore, collagen fiber thinning and expression of dysregulated collagens in LIM were ameliorated by 4-PBA administration. We demonstrate that scleral ER stress and PERK/ATF6 pathway controls axial elongation during the myopia development in vivo model and 4-PBA eye drop is promising drug for myopia suppression/treatment.

Comparisons of Three Methods for Myopia Control in Adolescents

Objective

A rising trend in electronic use has increased the prevalence of myopia in adolescents, but the optimal approach to controlling myopia remains undetermined. Here, we explored the effects of common single vision (SV) spectacle lenses combined with 0.01% atropine eye drops (SV + A), orthokeratology (OK) lenses, and peripheral defocus (PD) spectacle lenses on myopia control in adolescents.

Methods

Totally 150 myopic adolescent patients (300 eyes) receiving treatment at The First People's Hospital of Chenzhou City were enrolled. According to doctors' advice and guardians' wishes, the patients were divided into SV + A group, OK group, and PD group, with each group consisting of 50 cases (100 eyes). The spherical equivalent, axial length, accommodative response index (accommodative sensitivity and accommodative lag), and intraocular pressure were compared before and after 12 months of wearing lenses, and the complications were recorded.

Results

Before wearing lenses, there was no statistical significance in baseline characteristics such as age, gender, and spherical equivalent among the three groups (P > 0.05). After wearing lenses, the increase in spherical equivalent and axial length in the SV + A and OK groups were lower than in the PD group (P < 0.05), and the SV + A group had the lowest axial length growth. Compared with the SV + A group, accommodative sensitivity was much higher and accommodative lag was significantly lower in the OK and PD groups (P < 0.01). In addition, there was no significant difference in intraocular pressure before and after wearing lenses among the three groups (P > 0.05). Though the OK group patients had more complications, the difference was not statistically significant (P > 0.05).

Conclusion

SV + A, OK, and PD lenses can effectively control the progression of myopia in adolescents, but SV + A and OK lenses exhibited more significant effects.

A Latent Class Analysis of Student Eye Care Behavior: Evidence From a Sample of 6–17 Years Old in China

Purpose

To understand the latent classes and distribution of an adolescent eye care behavior, and to provide a basis for the formulation of appropriate adolescent vision health management interventions.

Methods

Information on eye behavior and eye health of primary and secondary school students in Wuhan was collected by multistage stratified cluster sampling. The latent class analysis (LCA) method was used to analyze the students' eye care behavior, and the latent class model (LCM) was built.

Results

A total of 6,130 students were enrolled in this study, of which 53.56% were males, aged from 6 to 17 years old, with an average age of 10.33 ± 2.60. The latent class results classified the adolescents' eye care behaviors into bad behaviors, moderate behaviors, and healthy behaviors. The model fitting results were as follows: Akaike Information Criterion (AIC) was 36,698.216, Bayesian Information Criterion (BIC) was 36,906.565, Adjusted Bayesian Information Criterion (aBIC) was 36,808.056, and entropy was 0.838.Compared with the healthy behaviors class, the bad behaviors class was more prevalent in high schools (p = 0.003), non-demonstration schools (p = 0.001), and most of this group had astigmatism (p = 0.002). The moderate behaviors class predominately consisted of females (p = 0.001), 15–17 years old (p = 0.005, 6~8 years old as the reference), from non-demonstration schools (p < 0.001), and most had myopia (p = 0.009).

Conclusion

There were differences in basic demographic characteristics, visual acuity development level, and family visual environment among different classes. In the management and intervention of an adolescent vision health, we should continue to promote the visual health management of adolescents based on visual monitoring and realize the early intervention and guidance of individuals in bad behaviors class.

Corneal morphology correlates with choriocapillaris perfusion in myopic children

AIMS

The present study investigated the difference in choriocapillaris (CC) perfusion between different AL/K ratio groups with similar spherical equivalent refraction (SER) and analyzed factors affecting CC perfusion.

METHODS

This cross-sectional study included 129 children with low-to-moderate myopia. Axial length (AL), average K-reading (Ave-K), and SER were measured. Choroidal vascularity, including the total choroidal area (TA), choroidal luminal area (LA), stromal area (SA), choroidal vascularity index (CVI), CC flow voids (FVs), and FVs%, was obtained using optical coherence tomography angiography.

RESULTS

Participants with similar SER were divided into two groups (high AL/K ratio, n = 57; low AL/K ratio, n = 72). The high AL/K group had lower LA, TA, and CVI (P < 0.01) and lower FVs (inner ring and fovea, P < 0.05) and FVs% (outer ring, inner ring, and fovea, P < 0.05). The AL/K ratio and FVs% were negatively correlated in the outer ring (r =  - 0.174, P < 0.05) and inner ring (r =  - 0.174, P < 0.05). The Ave-K and inner FVs (r = 0.178, P < 0.05), outer FVs% (r = 0.175, P < 0.05), and inner FVs% (r = 0.196, P < 0.05) were positively correlated. In stepwise multiple regression for the outer ring, the horizontal CVI was related to FVs (β = 0.175, P < 0.05), and the vertical CVI was related to FVs% (β = 0.232, P < 0.01). Independent risk factors associated with inner FVs area were vertical CVI (β = 0.329; P < 0.001) and SER (β =  - 0.196, P < 0.05); FVs% was also associated with vertical CVI (β = 0.360, P < 0.01) and SER (β =  - 0.196, P < 0.05).

CONCLUSION

With a similar SER, myopic eyes with a higher AL/K ratio maintained more CC perfusion and lower CVI, which may indicate rapid myopic progression. Low K-reading eyes had more CC perfusion and less CVI, which may explain the relatively poor myopia control efficacy in the clinic.

Identification of the Potential Key Genes and Pathways Involved in Lens Changes of High Myopia

Aim

Methods

Results

Conclusion

Multifocal contact lenses: A bibliometric study

PURPOSE

To analyze the state of scientific publications in multifocal contact lenses field through a bibliometric study.

METHODS

The database used to carry out the study was SCOPUS and contained the descriptors "multifocal contact lens", "bifocal contact lenses", "progressive contact lenses" and "presbyopia contact lenses", limited to the fields of title, keywords and abstract. The indicators applied in this research were: doubling time and annual growth rate, Price's transience index, Lotka's law of scientific productivity, and Bradford's zones.

RESULTS

A total of 346 articles were published between 1960 and 2019. The growth in the number of publications matches the exponential adjustment slightly better (R = 0.53). The duplication time was 13.2 years. The productivity level is focused on articles with an average number of authors of just 2.06 per article. The Bradford core was formed by two journals, Optometry and Vision Science and Eye and Contact Lens.

CONCLUSIONS

Research on multifocal contact lenses has exponential growth, without evidence of having reached a saturation point. The main countries in scientific production in this field are the United States and Australia.

Cumulative Childhood Adversity and Its Associations With Mental Health in Childhood, Adolescence, and Adulthood in Rural China

Capitalizing on a 15-year longitudinal dataset of 9-12 years old children in rural China, this study adopts a life course perspective and analyzes cumulative childhood adversity and its associations with mental health problems from childhood to adulthood. Four domains of childhood life are selected to construct cumulative childhood adversity: socioeconomic hardship, family disruption, physical issue, and academic setback. Overall, cumulative childhood adversity significantly associates with children's internalizing and externalizing problems as well as adults' depression and self-esteem. However, cumulative childhood adversity has no significant relationship with internalizing and externalizing problems in adolescence. Furthermore, different domains of childhood adversity matter differently for mental health problems in different life stages. Physical issue and academic setback have the strongest association with internalizing and externalizing problems in childhood, while only socioeconomic hardship has a significant relationship with depression and self-esteem in adulthood. The relationship between cumulative childhood adversity and adult mental health problems is fully mediated by educational attainment. Finally, there is no gender difference in either the occurrence of cumulative childhood adversity or the association between cumulative childhood adversity and mental health problems.

A multicenter Spanish study of atropine 0.01% in childhood myopia progression

To evaluate the efficacy and safety of atropine 0.01% eye drops for myopia control in a multicentric pediatric Spanish cohort. An interventional, prospective, multicenter study was designed. Children aged between 6 and 14 years, with myopia between - 2.00 D to - 6.00 D, astigmatism < 1.50 D and documented previous annual progression greater than - 0.5 D (cycloplegic spherical equivalent, SE) were included. Once nightly atropine 0.01% eye drops in each eye were prescribed to all participants for 12 months. Age, gender, ethnicity and iris color were registered. All patients underwent the same follow-up protocol in every center: baseline visit, telephone consultation 2 weeks later and office controls at 4, 8 and 12 months. At each visit, best-corrected visual acuity, and cycloplegic autorefraction were assessed. Axial length (AL), anterior chamber depth and pupil diameter were measured on an IOL Master (Carl Zeiss Meditec, Inc, Dublin, CA). Adverse effects were registered in a specific questionnaire. Mean changes in cycloplegic SE and AL in the 12 months follow-up were analyzed. SE progression during treatment was compared with the SE progression in the year before enrollment for each patient. Correlation between SE and AL, and annual progression distribution were evaluated. Progression risk factors were analyzed by multivariate logistic regression analyses. Of the 105 recruited children, 92 completed the treatment. Mean SE and AL changes were - 0.44 ± 0.41 D and 0.27 ± 0.20 mm respectively. Mean SE progression was lower than the year before treatment (- 0.44 ± 0.41 D versus - 1.01 ± 0.38 D; p < 0.0001). An inverse correlation between SE progression and AL progression (r: - 0.42; p < 0.0001) was found. Fifty-seven patients (62%) had a SE progression less than - 0.50 D. No risk factors associated with progression could be identified in multivariate analyses. Mean pupil diameter increment at 12-months visit was 0.74 ± 1.76 mm. The adverse effects were mild and infrequent, and decreased over the time. Atropine 0.01% is effective and safe for myopia progression control in a multicentric Spanish children cohort. We believe this efficacy might be extensible to the myopic pediatric population from Western countries with similar social and demographic features. More studies about myopia progression risk factors among atropine treated patients are needed.

Influence of Chronic Ocular Hypertension on Emmetropia: Refractive, Structural and Functional Study in Two Rat Models

Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (<20 mmHg) and an OHT cohort (>20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time.

Early Age of the First Myopic Spectacle Prescription, as an Indicator of Early Onset of Myopia, Is a Risk Factor for High Myopia in Adulthood

Purpose

The present study investigated the risk factors for high myopia in adulthood, with a focus on the age at which children wore their first spectacles.

Methods

Adults aged between 20 and 45 years were invited to complete a questionnaire about age, sex, current refractive error, high myopia in parents, early onset of myopia presented by the age of the first myopic spectacle prescription, refractive power of the first spectacles, and life habits at different educational stages. The associations between these factors and high myopia in adulthood were then evaluated and analyzed.

Results

In total, 331 participants were enrolled. Their average refractive error was −4.03 diopters, and high myopia was noted in 27.5% of the study participants. Only 3.3% of participants had fathers with high myopia, while 6.0% had mothers with high myopia. The participants received their first myopic spectacle prescription at a mean age of 13.35 years, with a mean refractive error of −1.63 diopters. The significant risk factors for developing high myopia in adult life were earlier age of the first spectacles prescribed (p < 0.001), higher refractive power of the first spectacles (p < 0.001), mother with high myopia (p=0.015), and after-school class attendance in senior high school (p=0.018). Those who wore their first spectacles at <9 years of age were more predisposed to high myopia than those who did so at ≧13 years, with an odds ratio of 24.9.

Conclusion

The present study shows that earlier onset of myopia, which is presented by the age of the first myopic spectacle prescription, higher myopic refraction of the first spectacles, mothers with high myopia, and after-school class attendance in senior high school are risk factors for high myopia in adulthood. It suggests that delaying the onset of myopia in children is important for the prevention of high myopia in later life.

Does Orthokeratology Wearing Affect the Tear Quality of Children?

Orthokeratology is currently known as one of the most effective methods of myopia control in the process of rapid deterioration of the global myopia prevalence. As orthokeratology is widely used, it is necessary to evaluate its complications reasonably and accurately. Eye surface problems in children, such as dry eyes, have received increasing attention. At present, there is no conclusive evidence on how orthokeratology affects the ocular surface, especially the tears. To our knowledge, this is the first study to explore the relationship between orthokeratology lenses and tears through meta-analysis. However, it is still challenging to get a convincing conclusion and a higher level of evidence in this meta-analysis. Reasons for this include limitation of study design, lack of clarity on important confounding factors, lack of appropriate statistical tools, and other biases. This paper will analyze the dilemma existing in the current research from different perspectives to provide meaningful information for future studies in this field.

Efficacy in myopia control

There is rapidly expanding interest in interventions to slow myopia progression in children and teenagers, with the intent of reducing risk of myopia-associated complications later in life. Despite many publications dedicated to the topic, little attention has been devoted to understanding 'efficacy' in myopia control and its application. Treatment effect has been expressed in multiple ways, making comparison between therapies and prognosis for an individual patient difficult. Available efficacy data are generally limited to two to three years making long-term treatment effect uncertain. From an evidence-based perspective, efficacy projection should be conservative and not extend beyond that which has been empirically established. Using this principle, review of the literature, data from our own clinical studies, assessment of demonstrated myopia control treatments and allowance for the limitations and context of available data, we arrive at the following important interpretations: (i) axial elongation is the preferred endpoint for assessing myopic progression; (ii) there is insufficient evidence to suggest that faster progressors, or younger myopes, derive greater benefit from treatment; (iii) the initial rate of reduction of axial elongation by myopia control treatments is not sustained; (iv) consequently, using percentage reduction in progression as an index to describe treatment effect can be very misleading and (v) cumulative absolute reduction in axial elongation (CARE) emerges as a preferred efficacy metric; (vi) maximum CARE that has been measured for existing myopia control treatments is 0.44 mm (which equates to about 1 D); (vii) there is no apparent superior method of treatment, although commonly prescribed therapies such as 0.01% atropine and progressive addition spectacles lenses have not consistently provided clinically important effects; (viii) while different treatments have shown divergent efficacy in the first year, they have shown only small differences after this; (ix) rebound should be assumed until proven otherwise; (x) an illusion of inflated efficacy is created by measurement error in refraction, sample bias in only treating 'measured' fast progressors and regression to the mean; (xi) decision to treat should be based on age of onset (or refraction at a given age), not past progression; (xii) the decreased risk of complications later in life provided by even modest reductions in progression suggest treatment is advised for all young myopes and, because of limitations of available interventions, should be aggressive.

A 3-year follow-up study of atropine treatment for progressive myopia in Europeans

BACKGROUND

Atropine is the most powerful treatment for progressive myopia in childhood. This study explores the 3-year effectiveness of atropine in a clinical setting.

METHODS

In this prospective clinical effectiveness study, children with progressive myopia ≥ 1D/year or myopia ≤ -2.5D were prescribed atropine 0.5%. Examination, including cycloplegic refraction and axial length (AL), was performed at baseline, and follow-up. Outcome measures were spherical equivalent (SER) and AL; annual progression of SER on treatment was compared with that prior to treatment. Adjustments to the dose were made after 1 year in case of low (AL ≥ 0.3 mm/year) or high response (AL < 0.1 mm/year) of AL.

RESULTS

A total of 124 patients were enrolled in the study (median age: 9.5, range: 5-16 years). At baseline, median SER was -5.03D (interquartile range (IQR): 3.08); median AL was 25.14 mm (IQR: 1.30). N = 89 (71.8%) children were persistent to therapy throughout the 3-year follow-up. Median annual progression of SER for these children was -0.25D (IQR: 0.44); of AL 0.11 mm (IQR: 0.18). Of these, N = 32 (36.0%) had insufficient response and were assigned to atropine 1%; N = 26 (29.2%) showed good response and underwent tapering in dose. Rebound of AL progression was not observed. Of the children who ceased therapy, N = 9 were lost to follow-up; N = 9 developed an allergic reaction; and N = 17 (19.1%) stopped due to adverse events.

CONCLUSION

In children with or at risk of developing high myopia, a starting dose of atropine 0.5% was associated with decreased progression in European children during a 3-year treatment regimen. Our study supports high-dose atropine as a treatment option for children at risk of developing high myopia in adulthood.

Topical bendazol inhibits experimental myopia progression and decreases the ocular accumulation of HIF-1α protein in young rabbits

PURPOSE

To investigate the inhibitory effect of bendazol on form-deprivation myopia (FDM) in rabbits as well as the underlying biochemical processes.

METHODS

Forty-eight 3-week-old New Zealand white rabbits were randomly assigned to three groups: a control group, a form-deprivation (FD) group and an FD + bendazol group (treated with 1% bendazol in the FD eyes). Refraction, corneal curvature, vitreous chamber depth (VCD) and axial length (AL) were assessed using streak retinoscopy, keratometry, and A-scan ultrasonography, respectively. Eyeballs were enucleated for histological analysis, and ocular tissues were homogenized to determine the mRNA and protein expression of hypoxia-inducible factor-1α (HIF-1α) and muscarinic acetylcholine receptors (mAChRs).

RESULTS

Bendazol inhibited the progression of FDM and suppressed the upregulation of HIF-1α. At week 6, in the control, FD and FD + bendazol groups, the refraction values were 1.38 ± 0.43, 0.03 ± 0.47 and 1.25 ± 0.35 D, respectively (p < 0.001); the ALs were 13.91 ± 0.11, 14.15 ± 0.06 and 13.97 ± 0.10 mm, respectively (p < 0.001) and the VCDs were 6.56 ± 0.06, 6.69 ± 0.07 and 6.61 ± 0.06 mm, respectively (p < 0.001). HIF-1α was upregulated in FD eyes but downregulated in FD + bendazol eyes, while the mAChRs were the opposite.

CONCLUSIONS

In the FD rabbit model, bendazol significantly inhibits the development of myopia and downregulates HIF-1α expression, which may provide a novel therapeutic approach for myopia control.

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.

The Combined Effect of Low-dose Atropine with Orthokeratology in Pediatric Myopia Control: Review of the Current Treatment Status for Myopia

Pediatric myopia has become a major international public health concern. The prevalence of myopia has undergone a significant increase worldwide. The purpose of this review of the current literature was to evaluate the peer-reviewed scientific literature on the efficacy and safety of low-dose atropine treatment combined with overnight orthokeratology for myopia control. A search was conducted in Pubmed and Web of Science with the following search strategy: (atropine OR low-dose atropine OR 0.01% atropine) AND (orthokeratology OR ortho-k) AND (myopia control OR myopia progression). All included studies improved myopia control by the synergistic effect of orthokeratology with low-dose atropine, compared with orthokeratology treatment alone. All studies included a short or medium follow-up period; therefore longer-term studies are necessary to validate these results.

Up-Regulation of Matrix Metalloproteinase-2 by Scleral Monocyte-Derived Macrophages Contributes to Myopia Development

Myopia is a leading cause of visual impairment worldwide. This sight-compromising condition is associated with scleral thinning, extracellular matrix remodeling, and inappropriate optical axial length elongation. Although macrophages are present in the sclera, their involvement in this condition is unknown. By using a form-deprivation myopia (FDM) mouse model, we found that both the scleral macrophage density and their matrix metalloproteinase-2 (MMP-2) expression levels increased in myopic eyes. Partial scleral macrophage depletion by clodronate shifted the refraction toward hyperopia in both the form-deprived and the untreated fellow eyes compared with their respective counterparts in the vehicle-injected control mice. However, this procedure did not alter susceptibility to FDM. FDM development was 59% less in the macrophage-specific Mmp2 deletion (LysM^CreMmp-2^fl/fl) mice than in their Cre-negative littermates (Mmp2^fl/fl mice). Moreover, the expression of scleral C-C motif chemokine ligand-2 (CCL2), which is a potent monocyte chemoattractant recruiting monocytes to tissue sites, was increased during myopia progression. However, the increase in the density of scleral macrophages and myopia development were suppressed in fibroblast-specific Ccl2 deletion mice. These declines suggested that the increase in scleral macrophage density in myopic eyes stems from the up-regulation of scleral Ccl2 expression in fibroblasts, which, in turn, promotes monocytes recruitment. In summary, scleral monocyte-derived macrophages contribute to myopia development through enhancing MMP-2 expression in mice.

The Prevalence of Myopia and Factors Associated with It Among Secondary School Children in Rural Vietnam

Purpose

To assess the prevalence of myopia and associated factors among secondary school children in a rural area of Vietnam.

Methods

A school-based cross-sectional study of children in grades six to nine was conducted in four secondary schools in Hoang Mai town, Nghe An Province, Vietnam, during December 2018 and January 2019. The status of myopia was defined as a spherical equivalent objective refractive error of −0.50 D or worse in either eye. A case–control study was conducted to explore factors associated with myopia, where children with myopia were considered to be cases, and children without myopia were considered to be controls. Factors associated with myopia were analyzed using univariate and multivariate logistic regression.

Results

The prevalence of myopia among secondary school children was 14.2% (95% CI: 12.7–15.7%) and tended to increase with grade, from 10.5% in grade six to 17.7% in grade nine. Myopia prevalence in girls was significantly higher than in boys. Factors associated with myopia were a mother with a college/university education (OR = 2.5, 95% CI = 1.2–5.3), parents who wore spectacles (OR = 2.0, 95% CI = 1.1–3.8), distance from near work (OR = 5.2, 95% CI = 3.5–7.9), and taking breaks after 30 minutes of continued reading (OR = 1.6, 95% CI = 1.1–2.5). However, there were inverse associations with myopia for children belonging to the wealthiest households (OR = 0.2, 95% CI = 0.1–0.5) and time spent performing outdoor activities (OR = 0.6, 95% CI = 0.4–0.9).

Conclusion

Our study showed that the prevalence of myopia is considerable among secondary children in rural areas of Vietnam. The prevalence of myopia tended to increase among children in higher grade levels. Thus, appropriate interventions should be developed and conducted to deal with the issue of school-age myopia.

Impact of peripheral optical properties induced by orthokeratology lens use on myopia progression

The objective of the present retrospective comparative cohort study was to compare the impact of wearing glasses versus an orthokeratology (Ortho-K) lens on peripheral optical properties and myopia progression in a population of South Korean children. Participants included children with myopia, between 8 and 12 years of age (n = 22 eyes), and divided into two groups: those who used glasses (Group I, n = 9) and those who used an Ortho-K lens (Group II, n = 13). Myopia progression over one year was quantified by changes in the central axial length of the eye. Keratometry and corneal aberrations on both the anterior and posterior surfaces of the eye were obtained using a Scheimpflug camera. A custom-developed Shack-Hartmann aberrometer was also used to measure peripheral aberrations across the horizontal visual field, up to 30°, and along the nasal-temporal meridian in 10-degree steps. Central axial elongation was larger in Group I (0.59 ± 0.21 mm) than in Group II (0.34 ± 0.18 mm) (P = .01). Relative peripheral spherical refractions at 10 and 20° nasally and at 10° temporally (P = 0.04, 0.049, and 0.042, respectively) relative to the fovea were positively correlated with central axial elongation in Group II. Group II exhibited an increase in peripheral ocular high order aberrations, such as horizontal coma and asymmetric trefoil. The use of Ortho-K lenses was found to slow the rate of central axis elongation in children with myopia. This effect might be related to an increase in both peripheral spherical refraction and peripheral ocular higher order aberrations with Ortho-K lens use.

Clinical efficacy of femtosecond laser for myopia: A systematic review protocol of randomized controlled trial

BACKGROUND

Femtosecond laser (FL) is an effective method to treat patients with myopia, but its relative efficacy and safety is still unclear. Thus, this study will be conducted to assess the efficacy and safety of FL for myopia systematically.

METHODS

This study will systematically retrieve the following electronic databases up to the present: Cochrane Library, PubMed, EMBASE, Web of Science, PsycINFO, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, Wanfang, VIP, and China National Knowledge Infrastructure. All electronic databases will be searched without any limitations of language and publication status. RevMan 5.3 software will be utilized for statistical analysis.

RESULTS

We will summarize the targeted results evaluating the efficacy and safety of FL for patients with myopia.

CONCLUSIONS

This study will provide a comprehensive evidence summary on FL for patients with myopia.PROSPERO registration number: PROSPERO CRD42019148659.

Multifocal spectacles in childhood myopia: Are treatment effects maintained? A systematic review and meta-analysis

We evaluate the impact of duration on the treatment effect of multifocal spectacle lenses used to inhibit myopia progression in children. A systematic literature search identified randomized controlled trials where multifocal lenses were prescribed as the intervention, with single-vision lenses as the control. Nine randomized control trials involving 1,701 children aged 8-13 years were included in the meta-analysis. Treatment effects, that is, differences in spherical equivalent refraction between intervention and nonintervention groups, were analyzed over both 6- and 12-month intervals. As treatment duration increased, effectiveness reduced. In 6-month intervals, treatment effects were 0.07 D (95 % CI 0.02, 0.13), 0.03 D (95% CI -0.02, 0.08), and 0.02 D (95% CI -0.05, 0.11) for baseline to 6, 6-12, and 12-18 months, respectively. For 12-month intervals, treatment effects were 0.21 D (95% CI 0.12, 0.29), 0.11 D (95% CI 0.03, 0.19), and 0.12 D (95% CI -0.01, 0.25) for baseline to 12, 12-24, and 24-36 months, respectively. Even during the second 6 months of wear, the ability of multifocal spectacle lenses to inhibit myopia progression was reduced. It is not appropriate to extrapolate the treatment effect observed in the first 6 months or 12 months to estimate the likely future benefit of treatment.

IMI - Industry Guidelines and Ethical Considerations for Myopia Control Report

Purpose

To discuss guidelines and ethical considerations associated with the development and prescription of treatments intended for myopia control (MC).

Methods

Critical review of published papers and guidance documents was undertaken, with a view to carefully considering the ethical standards associated with the investigation, development, registration, marketing, prescription, and use of MC treatments.

Results

The roles and responsibilities of regulatory bodies, manufacturers, academics, eye care practitioners, and patients in the use of MC treatments are explored. Particular attention is given to the ethical considerations for deciding whether to implement a MC strategy and how to implement this within a clinical trial or practice setting. Finally, the responsibilities in marketing, support, and education required to transfer required knowledge and skills to eye care practitioners and academics are discussed.

Conclusions

Undertaking MC treatment in minors creates an ethical challenge for a wide variety of stakeholders. Regulatory bodies, manufacturers, academics, and clinicians all share an ethical responsibility to ensure that the products used for MC are safe and efficacious and that patients understand the benefits and potential risks of such products. This International Myopia Institute report highlights these ethical challenges and provides stakeholders with recommendations and guidelines in the development, financial support, prescribing, and advertising of such treatments.

Practice patterns to decrease myopia progression differ among paediatric ophthalmologists around the world

Introduction

Myopia is a worldwide epidemic. Plethora of treatments are offered to decrease myopia progression. In this study, we compared between different geographical areas worldwide the practice patterns used by paediatric ophthalmologists to decrease the progression of myopia.

Methods

Global responses to a questionnaire were analysed (n=794) for demographic variations. Pharmacological, optical and behavioural categories were defined as effective or ineffective based on the current scientific peer reviewed literature.

Results

Treatment rates varied significantly between geographical regions (mean 57%, range 39%–89%, p<0.001). Nearly all participants who treat myopia used at least one form of effective treatment, regardless of location (98%, p=0.16). Among those prescribing pharmacological treatments, European physicians offered the lowest rate of effective treatment compared with other regions (85% vs mean 97%). Rates of effective optical treatment varied significantly between locations (p<0.001), from 16% (Central-South America) to 56% (Far East). Most treating respondents advocated behavioural modifications (92%), between 87% (North America) and 100% (Central Asia). Nearly all respondents used combinations of treatment modalities (95%)—mostly pharmacological, optical and behavioural combination. However, combination rates varied significantly between regions (p<0.001).

Discussion

The utility of treatment to decrease myopia progression differs significantly across the world both in type, combination and efficacy.

Conclusion

Paediatric ophthalmologists involvement and proficiency in myopia progression treatment varies around the world. This may entail promoting continuous medical education and other incentives to increase the number and proficiency of paediatric ophthalmologist to have a more effective impact to control the myopia epidemic in children.

A Nationwide Study of Myopia in Taiwanese School Children: Family, Activity, and School-Related Factors

The purpose of the study was to explore how fixed and modifiable family, activity, and school factors affect a student's myopia risk and severity. We used national cross-sectional data from Taiwanese children in Grades 4-6. Bivariate and multivariate analyses, including logistic and ordinary least squares regression, examined factors related to children's myopia status and severity. Age, parent myopia, and school district were associated with risk of myopia. One hour or more per day of near work (OR = 1.26) increased the odds of myopia. The same amount of time in outdoor activities (OR = 0.85) or moderate or vigorous physical activities (OR = 0.82) was associated with lower risk. Near work (β = 0.06), outdoor activity (β = -0.04), and outdoor recess (β = -0.03) predicted myopia severity. To promote healthy vision, nurses should advocate for and implement interventions that increase school children's time outdoors and in physical activities and reduce their time on near work.

Using Decision Curve Analysis to Evaluate Common Strategies for Myopia Screening in School-Aged Children

Purpose: To evaluate common strategies for screening myopia. Methods: A total of 2,248 children aged 6 to 12 years from five randomly selected primary schools were included for the screening. Enrolled study participants underwent distant uncorrected visual acuity (UCVA, Standard Logarithmic Visual Acuity E Chart) and non-cycloplegic auto-refraction (NCAR, Topcon KR-8800). Among them, 1,639 children (72.9%) accepted cycloplegic auto-refraction. Taking rejection of cycloplegia into account, receiver operating characteristic curves were drawn to compare the accuracies of the four strategies (I, Cycloplegic auto-refraction; II, NCAR; III, UCVA; IV, Combination of UCVA and NCAR). Decision curve analysis (DCA) was used to compare net benefits. Tenfold cross-validation was used for statistical analyses. Results: For myopia (spherical equivalent refraction, SE ≤ -0.5D) screening, the mean sensitivities were 73.79% (SD: 5.40%), 85.57% (6.84%), 59.71% (13.49%), and 85.06% (6.68%) for Strategy I to IV; with mean specificities of 100% (0%), 87.43% (4.27%), 89.74% (10.25%), and 88.65% (5.07%), respectively. For screening early myopia (SE ≤ -0.5D and ≥-1.0D), the mean sensitivities were 73.44% (7.69%), 82.39% (5.32%), 54.27% (14.58%), and 81.76% (9.60%) for Strategy I to IV; with mean specificities of 100% (0%), 79.13% (4.86%), 85.48% (9.86%), and 81.17% (4.16%). Based on DCA, the net benefits of Strategy IV were the highest, with the probability thresholds ranging from 12% to 50%, after adjusting the TestHarms. For early myopia, the net benefits of Strategy IV were the highest with the probability threshold ranging from 5% to 34%. Conclusion: Combination of UCVA and NCAR produced the highest net benefits for myopia screening.

Myopia Growth Chart Based on a Population-Based Survey (KNHANES IV-V): A Novel Prediction Model of Myopic Progression in Childhood

PURPOSE

To introduce a novel myopia growth chart based on a population-based survey for the prediction of myopic progression.

METHODS

The study included 7,695 Korean participants aged 5 to 20 years from a population-based health survey (Korean National Health and Nutrition Examination Survey IV-V). The authors collected spherical equivalent (SE) data converted from noncycloplegic refraction data. To create a myopia growth chart, data were arranged in the order of SE from hyperopia to myopia to acquire specific percentiles of the SE by age. Myopia progression rates were calculated between two specific ages in each percentile.

RESULTS

The mean age of the participants was 11.8 years and the mean SE was -1.82 diopters (D). The SE of the 10th percentile was +0.72 D for participants aged 5 and -0.25 D for those aged 20 years, resulting in a total change in refraction of -0.97 D. In contrast, the SE of the 90th percentile was -0.75 D for participants aged 5 years and -6.73 D for those aged 20 years, showing myopia progression of -5.98 D. The myopia progression rate from 5 to 20 years of age was estimated as -0.06, -0.15, and -0.40 D/year in the 10th, 50th, and 90th percentile groups, respectively.

CONCLUSIONS

The myopia growth chart may be used to diagnose the severity or to estimate the progression of myopia. A patient in a higher percentile of myopia for his or her age may have myopia progressing at a faster rate and thus require close observation. [J Pediatr Ophthalmol Strabismus. 2019;56(2):73-77.].

Disease patterns of microbial keratitis in Singapore: A retrospective case series

PURPOSE

To investigate the disease patterns of Microbial Keratitis(MK) in patients seen in a tertiary referral hospital, to evaluate the clinical outcomes of MK and the risk factors for poorer visual outcomes.

METHODS

This is a retrospective case series of all culture-positive corneal scrapings between April 2012 and October 2016. A total of 230 patients(n = 230) were included into this study. Patient demographics, clinical information and microbiological characteristics of organisms are collected.

RESULTS

64.3% of patients with MK are contact lens(CL) users. Among CL users, there is a preponderance of females(68.9%) and they tend to be younger (27.1 ± 10.6 years). The most frequently isolated organism in this study is Pseudomonas aeruginosa(51.7%) with 69.6% of cases belonging to CL users. MK in non-CL users tend to involve other organisms, such as coagulase-negative Staphylococci, Staphylococcus aureus and Streptococcus pneumoniae. Pseudomonas aeruginosa exhibits good sensitivity rates to ciprofloxacin, levofloxacin and gentamicin. Non-Pseudomonas organisms display similar sensitivities to ciprofloxacin, levofloxacin and gentamicin. MK in non-CL users is related to predisposing factors of prior ocular trauma and concomitant ocular pathology. They tend to have worse visual acuity(VA) on presentation and after treatment compared to CL users. Poorer VA outcome is associated with larger ulcers, increasing age, trauma and non-CL wearers. Successful clinical outcome is achieved in 97.8% of patients, with only 2.2% requiring further surgical intervention.

CONCLUSION

CL use alters the disease patterns of MK as well as the underlying microbiological etiology. Fluoroquinolones and aminoglycosides are good empirical antibiotics for MK treatment. Early referral to a tertiary centre will likely allow for earlier treatment, which can result in better VA outcome, especially so in patients who are older, non-CL wearers and have larger ulcers with associated trauma.

The Topographical Effect of Optical Zone Diameter in Orthokeratology Contact Lenses in High Myopes

Purpose

To evaluate the effect of the optical zone diameter (OZ) in orthokeratology contact lenses regarding the topographical profile in patients with high myopia (−4.00 D to −7.00 D) and to study its effect over the visual quality.

Materials and Methods

Twelve patients (18 eyes) were fitted with overnight orthokeratology (OrthoK) with a randomized 6 mm or 5 mm OZ lens worn for 2 weeks, followed by a 2-week washout period, between both designs. Keratometry (K) readings, optical zone treatment diameter (OZT), peripheral ring width (PRW), higher-order aberrations (HOA), high (HC) and low contrast (LC) visual acuity, and subjective vision and comfort were measured at baseline and after 2 weeks of OrthoK lens wear of each contact lens.

Results

No significant differences were found between any measurements for the same subject at both baselines (p value > 0.05). There was no difference between OZ lens designs found in refraction, subjective vision or comfort, and HC and LC visual acuity. Contrast sensitivity was decreased in the 5 mm OZ lens design compared with 6 mm OZ design (p-value < 0.05). 5 mm OZ design provoked a greater flattening, more powerful midperipheral ring and 4^th-order corneal and total spherical aberration than the 6 mm OZ design, being statistically significant after 7 days, for corneal aberration, and 15 days, for corneal and total, of wearing the lens (p-value < 0.05). The OZT obtained were 2.8 ± 0.2 mm and 3.1 ± 0.1 mm for 5 mm and 6 mm OZ design, respectively (p-value < 0.05). Regarding PRW, the 5 mm OZ design had a wider ring width in both the nasal and temporal zones (p-value < 0.05).

Conclusions

A smaller diameter optical zone (5 mm) in orthokeratology lenses produces a smaller treatment area and a larger and more powerful midperipheral ring, increasing the 4^th-order spherical aberration that affects only the contrast sensitivity but without differences in visual acuity and subjective vision compared with a larger OZ diameter (6 mm).

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.

Scleral hypoxia is a target for myopia control

Worldwide, myopia is the leading cause of visual impairment. It results from inappropriate extension of the ocular axis and concomitant declines in scleral strength and thickness caused by extracellular matrix (ECM) remodeling. However, the identities of the initiators and signaling pathways that induce scleral ECM remodeling in myopia are unknown. Here, we used single-cell RNA-sequencing to identify pathways activated in the sclera during myopia development. We found that the hypoxia-signaling, the eIF2-signaling, and mTOR-signaling pathways were activated in murine myopic sclera. Consistent with the role of hypoxic pathways in mouse model of myopia, nearly one third of human myopia risk genes from the genome-wide association study and linkage analyses interact with genes in the hypoxia-inducible factor-1α (HIF-1α)-signaling pathway. Furthermore, experimental myopia selectively induced HIF-1α up-regulation in the myopic sclera of both mice and guinea pigs. Additionally, hypoxia exposure (5% O₂) promoted myofibroblast transdifferentiation with down-regulation of type I collagen in human scleral fibroblasts. Importantly, the antihypoxia drugs salidroside and formononetin down-regulated HIF-1α expression as well as the phosphorylation levels of eIF2α and mTOR, slowing experimental myopia progression without affecting normal ocular growth in guinea pigs. Furthermore, eIF2α phosphorylation inhibition suppressed experimental myopia, whereas mTOR phosphorylation induced myopia in normal mice. Collectively, these findings defined an essential role of hypoxia in scleral ECM remodeling and myopia development, suggesting a therapeutic approach to control myopia by ameliorating hypoxia.

The increasing prevalence of myopia and high myopia among high school students in Fenghua city, eastern China: a 15-year population-based survey

BACKGROUND

Myopia is the leading cause of preventable blindness in children and young adults. Multiple epidemiological studies have confirmed a high prevalence of myopia in Asian countries. However, fewer longitudinal studies have been performed to evaluate the secular changes in the prevalence of myopia, especially high myopia in China. In the present study, we investigated trends in the prevalence of myopia among high school students in Fenghua city, eastern China, from 2001 to 2015.

METHODS

This was a population-based, retrospective study. Data were collected among 43,858 third-year high school students. Noncycloplegic autorefraction was used to determine refractive error, which was defined as low myopia, moderate myopia, high myopia and very high myopia according to the spherical equivalent from the worse eye of each participant. The prevalence of myopia was calculated and the annual percentage change (APC) was used to quantify the time trends. All analyses were conducted using the SPSS, Stata and Graphpad Prism software.

RESULTS

From 2001 to 2015, the prevalence of overall myopia increased from 79.5% to 87.7% (APC =0.59%), with a significant increase of moderate myopia (38.8% to 45.7%, APC = 0.78%), high myopia (7.9% to 16.6%, APC = 5.48%) and very high myopia (0.08% to 0.92%, APC = 14.59%), while the prevalence of low myopia decreased from 32.7% to 24.4% (APC = - 1.73%). High myopia and very high myopia contributed the major part of the increasing trend of myopia prevalence (contribution rate 27.00% and 69.07%, respectively).

CONCLUSIONS

During the 15-year period, there was a remarkable increase in the prevalence of high and very high myopia among high school students, which might become a serious public health problem in China for the next few decades.

Short-Term Deposition of PM2.5 Particles on Contact Lens Surfaces: Effect on Oxygen Permeability and Refractive Index

PURPOSES

To identify the deposition of fine (≤2.5 μm diameter) particulate matter (PM) particles (PM_2.5) on contact lens surfaces and to investigate the effects of such deposition on the oxygen permeability (OP) and refractive index (RI) of contact lenses.

METHODS

A total of 36 contact lenses, including rigid gas permeable (RGP) lens and soft contact lens (SCL), were investigated. RGP lens (n=12) and SCL (n=12) (experimental group) were incubated in a PM_2.5 solution for 24 h, after which PM_2.5-treated RGP lens (n=6) and SCL (n=6) were further washed for 1 h in phosphate-buffered saline (PBS). All lenses were examined by field emission scanning electron microscopy. OP and RI of all lenses were measured.

RESULTS

Average-sized PM_2.5 particles deposited on RGP contact lens and SCL surfaces after immersion in the PM_2.5 solution were 3.192 ± 1.637 and 2.158 ± 1.187/100 μm², respectively. On RGP lens surfaces, we observed both large (≥2.5 µm diameter) and small (PM_2.5) particles. PM_2.5 particles were deposited in diffuse patterns, primarily along the honeycomb structural border of SCL, while no PM_2.5 particles were found in the honeycomb hole of SCL surfaces. Washing in PBS removed the larger PM particles from RGP lens surfaces, but left copious amounts of PM_2.5 particles. In contrast, nearly all PM particles were removed from SCL surfaces after PBS washing. OP values of RGP lens and SCL appeared to be unchanged by PM_2.5 deposition. RI values increased in both RGP lens and SCL groups after PM_2.5 deposition. However, these increases were not statistically significant, suggesting that PM_2.5 deposition itself does not cause fluctuations in contact lens RI.

CONCLUSIONS

Deposition of PM_2.5 particles on contact lens surfaces varies according to lens material. PM_2.5 particles deposited on SCL, but only large particles on RGP surfaces were able to be removed by washing in PBS and did not appear to alter OP and RI of either lens type.

Superdiluted atropine at 0.01% reduces progression in children and adolescents. A 5 year study of safety and effectiveness

OBJECTIVE

To confirm the clinical security and effectiveness of the daily application of 0.01% superdiluted atropine eyedrops in the progression of myopia in children.

MATERIAL AND METHODS

A total of 200 children 9-12 years of age were randomised into a treated group and a control without treatment. Refraction under cycloplegia was performed.

RESULTS

Myopia progression of the treated group was -0.14±0.35 versus -0.65±0.54 in the control group without treatment. Only 2% of patients were forced to stop treatment due to side effects.

CONCLUSION

Atropine superdiluted atropine 0.01% eyedrops is effective and well tolerated, and reduced myopia progression by 25%.