Epidemiologic study of ocular refraction among schoolchildren in Taiwan in 1995

Handheld chromatic pupillometry can reliably detect functional glaucomatous damage in eyes with high myopia

BACKGROUND/AIMS

To assess pupillary light responses (PLRs) in eyes with high myopia (HM) and evaluate the ability of handheld chromatic pupillometry (HCP) to identify glaucomatous functional loss in eyes with HM.

METHODS

This prospective, cross-sectional study included 28 emmetropes (EM), 24 high myopes without glaucoma (HM) and 17 high myopes with confirmed glaucoma (HMG), recruited at the Singapore National Eye Center. Monocular PLRs were evaluated using a custom-built handheld pupillometer that recorded changes in horizontal pupil radius in response to 9 s of exponentially increasing blue (469.1 nm) and red (640.1 nm) lights. Fifteen pupillometric features were compared between groups. A logistic regression model (LRM) was used to distinguish HMG eyes from non-glaucomatous eyes (EM and HM).

RESULTS

All pupillometric features were similar between EM and HM groups. Phasic constriction to blue (p<0.001) and red (p=0.006) lights, and maximum constriction to blue light (p<0.001) were reduced in HMG compared with EM and HM. Pupillometric features of melanopsin function (postillumination pupillary response, PIPR area under the curve (AUC) 0-12 s (p<0.001) and PIPR 6 s (p=0.01) to blue light) were reduced in HMG. Using only three pupillometric features, the LRM could classify glaucomatous from non-glaucomatous eyes with an AUC of 0.89 (95% CI 0.77 to 1.00), sensitivity 94.1% (95% CI 82.4% to 100.0%) and specificity 78.8% (95% CI 67.3% to 90.4%).

CONCLUSION

PLRs to ramping-up light stimuli are unaltered in highly myopic eyes without other diagnosed ocular conditions. Conversely, HCP can distinguish glaucomatous functional loss in eyes with HM and can be a useful tool to detect/confirm the presence of glaucoma in patients with HM.

Scanning Laser Ophthalmoscopy Demonstrates Pediatric Optic Disc and Peripapillary Strain During Horizontal Eye Rotation

Purpose: We employed automated analysis of scanning laser ophthalmoscopy (SLO) to determine if mechanical strains imposed on disc, and retinal and choroidal vessels during horizontal duction in children differ from those of adults.Methods: Thirty-one children aged 11.3 ± 2.7 (standard deviation) years underwent SLO in central gaze, and 35° ab- and adduction. Automated registration with deep learning-based optical flow analysis quantified vessel deformations as horizontal, vertical, shear, and equivalent strains. Choroidal vessel displacements in lightly pigmented fundi, and central disc vessel displacements, were also observed.Results: As in adults, strain in vessels during horizontal duction was greatest at the disc and decreased with distance from it. Strain in the pediatric disc was similar to published values in young adults,1 but in the peripapillary region was greater and propagated significantly more peripherally to at least three disc radii from it. During adduction in children, the nasal disc was compressed and disc vessels distorted, but the temporal half experienced tensile strain, while peripapillary tissues were compressed. The pattern was similar but strains were less in abduction (p < .001). Choroidal vessels were visualized in 24 of the 62 eyes and shifted directionally opposite overlying retinal vessels.Conclusions: Horizontal duction deforms the normal pediatric optic disc, central retinal vessels, peripapillary retina, and choroid, shearing the inner retina over the choroid. These mechanical effects occur at the sites of remodeling of the disc, sclera, and choroid associated with typical adult features that later emerge later, including optic cup enlargement, temporal disc tilting, and peripapillary atrophy.

Determinants of Health Care Needs in Relation to Vision Correction among Adolescents in the United Arab Emirates: A Cross-Sectional Study

BACKGROUND

Uncorrected refractive error has been suggested to affect children's development, educational performance, and socialization. Sociodemographic and environmental differences among individuals may impact their accessibility to utilizing appropriate services, impacting their vision-dependent activities.

METHODS

Guided by the population health framework, this retrospective study assessed the prevalence of self-reported vision correction needs and its determinants for a sample of adolescents (n = 6363) from the United Arab Emirates (UAE) aged 13 to 20 years between 2007 to 2009.

RESULTS

The findings suggest a relatively high prevalence of self-reported vision correction needs (26.8%), with among 24.8% males and 31.7% among females. Factors that were significantly associated with vision correction needs included age, biological sex, location of residence (emirate), nationality, parental education and employment level, household financial status, screen time use, visiting an eye specialist in the past year, and daily functional capacity.

CONCLUSION

Reporting the vision correction needs of the adolescent population and identifying its determinants may help identify and resolve modifiable barriers to accessing the appropriate vision care resources. Further research in assessing the type of refractive error, potential genetic and environmental factors, and vision care services in each emirate may help decision-makers set appropriate policies to improve the overall quality of eye health.

Progression and incidence of myopia among schoolchildren in the post-COVID-19 pandemic period: a prospective cohort study in Shantou, China

OBJECTIVES

To determine the progression and incidence of myopia in Chinese schoolchildren in the post-COVID-19 pandemic period in Shantou, China.

DESIGN

Prospective cohort study.

SETTING

Shantou Myopia Study, China.

PARTICIPANTS

1-year follow-up data were available for 621 881 schoolchildren (301 999 females). Data on spherical equivalent refraction (SER) were collected.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes were myopia progression and incidence. Myopia progression is defined as a change of SER towards the negative direction in the follow-up visit. Incidence is defined as the proportion of schoolchildren who were not myopic but developed myopia in the follow-up study. Age, sex and SER at baseline were evaluated as associated factors for myopia burden, which were defined as the secondary outcomes.

RESULTS

Mean progression of SER was -0.35±0.97 D for the population (ranging from -0.06 D at 18 years of age to -0.46 D at 11 years of age), with a rapid myopic progression for students at the age of 10-12 years (-0.50 D in girls and -0.44 D in boys). A myopic shift greater than -0.50 D/year occurred in 256 299 eyes (41.21%). Myopic progression in refraction was associated with the 10-12 years age groups (OR 1.42; 95% CI 1.39 to 1.45, p<0.001), female sex (OR 1.09; 95% CI 1.08 to 1.10, p<0.001) and higher refractive errors at baseline (OR>1.00, p<0.001). The annual incidence of myopia among schoolchildren was 24.85%, with an incidence of 26.69% in girls and 23.02% in boys.

CONCLUSIONS

Our study revealed an annual myopia progression of -0.35 D and an incidence of 24.85% among schoolchildren in the post-COVID-19 pandemic period. Myopia progressed rapidly at 10-12 years of age, with -0.50 D in girls and -0.44 D in boys. The incidence was higher for children aged 10-11 years and for girls.

The use of progressive addition lenses to improve the daily visual function of children receiving topical atropine treatment

PURPOSE

To evaluate the changes in visual function when progressive addition lenses (PAL) are added in children using topical atropine as a myopia control therapy. Daily visual complaints and the determination of their near correction were studied.

METHODS

Forty children aged 7-12 years were recruited. Distance and near visual acuity, accommodative lag, heterophoria, near point of convergence and stereopsis were examined, and a questionnaire of daily visual complaints was administered.

RESULTS

Significant differences in visual functions were found after the near correction was prescribed. Significant improvements in distance and near visual acuity, lag of accommodation and binocular visual function were observed, and fewer visual complaints were reported at the Harmon distance.

CONCLUSION

The use of PAL is helpful for children undergoing topical atropine treatment for myopia control, particularly those receiving medium to high doses. This combination therapy could also be applied to younger children who have a low tolerance to contact lenses, with less risk of ocular adverse effects.

Superficial Retinal Vessel Density and Foveal Avascular Zone in Myopic Anisometropia: An OCTA-Based Study in Young Chinese Children

This retrospective study investigated superficial retinal vessel density (SRVLD) and foveal avascular zone (FAZ) area using optical coherence tomography angiography (OCTA) in children with myopic anisometropia. We included 84 eyes of 42 individuals with myopic anisometropia and no posterior segment abnormalities. All eyes underwent OCTA. Individual SRVLD and FAZ area were measured on OCTA. Using a paired t-test, we compared the interocular difference between the fellow eyes for all the measurements. SRVLD was significantly higher in the relatively more myopic eyes than in the fellow eyes in the whole population and in patients with an interocular difference of >1.5 D (p = 003 and 0.01, respectively). In patients with an interocular difference of ≤1.5 D in spherical equivalent refraction, only the nasal sector showed higher SRVLD in the less myopic eyes. SRVLD in the whole image and parafoveal sector was significantly lower in the dominant eye (paired t-test, p = 003 and 0.03, respectively), while other locations showed no difference. The area, perimeter, and circularity index in FAZ parameters showed no difference. SRVLD showed no significant differences between the two types of eyes, with an interocular difference of ≤1.5 D but increased in the relatively more myopic eyes than in the fellow eyes in children with myopic anisometropia, with an interocular difference of >1.5 D. Increasing SRVLD may show a compensatory increase to maintain retinal function and thus maintain normal visual function in the relatively more myopic fellow eyes. As the study to use patients as self-control with OCTA analysis in both eyes, this study provides some reference value for further interpretation of the pathogenesis of anisometropia.

Biomechanical changes in myopic sclera correlate with underlying changes in microstructure

Myopia alters the microstructural and biomechanical properties of the posterior sclera, which is characterized as a layered structure with potentially different inter-layer collagen fibril characteristics. Scanning acoustic microscopy (SAM) has been used to investigate how the micron-scale bulk mechanical properties of the posterior sclera are affected by myopia. Other investigators have employed second harmonic generation (SHG) imaging to characterize the collagen microstructure of tissues. In the present study, SAM and SHG imaging were used to investigate the existence of biomechanically-distinct scleral layers and identify relationships between mechanical properties and tissue microstructure in myopic guinea pig (GP) eyes. Diffusers were worn over the right eyes of six, 1-week-old GPs for one week to induce unilateral form-deprivation myopia. GPs were euthanized, enucleated, and eyes were cryosectioned. Twelve-micron-thick adjacent vertical cryosections were scanned with SAM or SHG. SAM maps of bulk modulus, mass density, and acoustic attenuation were estimated. A fiber-extraction algorithm applied to SHG images estimated collagen fiber length, width, straightness, alignment, and number density. Results revealed that the posterior sclera may exhibit biomechanically distinct layers that are affected differently in myopia. Specifically, a layered structure was observed in the mechanical-parameter maps of control eyes that was less apparent in myopic eyes. Collagen fibers in myopic eyes had smaller diameters and were more aligned. Myopia-associated biomechanical changes were most significant in the outermost and innermost scleral layers. SAM-measured mechanical parameters were correlated with collagen fiber microstructure, particularly fiber length, alignment, and number density, which may imply the biomechanical parameters estimated from SAM measurements are related to tissue microstructure. Interestingly, some changes were greatest in more-peripheral regions, suggesting interventions to strengthen the sclera may be effective away from the optic nerve and efficacy may be achieved best when intervention is applied to the outermost layer.

The change of myopic prevalence in children and adolescents before and after COVID-19 pandemic in Suqian, China

Purpose

The aim of this study was to investigate the change of myopic prevalence in students with different demographic characteristics before and after the COVID-19 pandemic in Suqian, China.

Methods

A retrospective, cross-sectional study was conducted. Student data from 52 schools in 2019 and 2020 were collected from the electronic medical records database through cluster sampling. Ophthalmic examinations were conducted on students from September to December in 2019 and 2020. Measurements of uncorrected visual acuity (UCVA) and noncycloplegic autorefraction were included to obtain the spherical equivalent refraction (SER) and prevalence of myopia. The difference in the rate of myopia and SER of students ages 6 to 18 with various demographic characteristics was compared between the two years.

Results

Records from 118,479 students in 2019 and the 121,881 students in 2020 were obtained. In 2019 and 2020, the prevalence of overall myopia increased from 43.1% to 48.9% (5.8 percentage point), and a substantial shift in myopic rate occurred in grades 4 to 6 (6.9 percentage point). The change in the prevalence of myopia in girls (5.9 percentage point) was approximately equal to that in boys (5.8 percentage point) and it was more common in rural students (5.9 percentage point) than in urban students (5.1 percentage point). The prevalence of low myopia increased more in children, and the prevalence of moderate myopia increased more in adolescents. The mean spherical equivalent refraction (SER) (-1.34±2.03 D) was lower in 2020 than in 2019 (-1.16±1.92 D), while SER decreased mainly at ages 7 to 15. The SER presented myopic status at the age of 9 (-0.55±1.26 D in 2019, -0.71±1.42 D in 2020), and attained moderate myopia at the age of 15 (-3.06±2.41 D in 2019, -3.22±2.40 D in 2020).

Conclusions

After the COVID-19 pandemic, myopia increased in this population with variable rates of increase in different demographic groups. The change of myopia in children was comparatively greater than that in adolescents. Therefore, we should take measures to prevent and control the development of myopia after the COVID-19 pandemic, especially for younger students.

Association of School Education With Eyesight Among Children and Adolescents

IMPORTANCE

Myopia in youths is an increasingly common global problem, associated with significant social and economic burden worldwide.

OBJECTIVES

To explore the association of school education with myopia and investigate its scale, controlling confounding factors, such as age and socioeconomic status.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted from July 2019 to December 2020 using regression discontinuity (RD) based on the Compulsory Education Law to examine the complex association of school education with myopia. Participants were youths from grades 1 to 12 before tertiary or university studies in China, including individuals from 815 primary schools, 373 junior high schools, and 145 senior high schools. Data were analyzed from February through June 2021.

EXPOSURES

Participants born earlier in a year (ie, January to August) were assigned 1 more year of education and were considered to be in the treated group, while participants born September to December were considered to be in the control group.

MAIN OUTCOMES AND MEASURES

Differences in mean spherical equivalent refractive error (MSE) and uncorrected visual acuity (UVA) between treated and control groups were calculated.

RESULTS

Among a mean (SD) of 812 979 (55 953) participants across 5 surveys survey (mean SD 44.9% [0.5%] female participants; mean [SD] age, 11.19 [2.60] years), the mean (SD) MSE was -1.30 (2.93) diopters and mean (SD) UVA was 4.77 (0.34) points. Every additional year at school was associated with an decrease in MSE of -0.17 diopters/y (95% CI, -0.22 to -0.11 diopters/y) and a decrease in UVA of -0.03 points/y (95% CI, -0.04 to -0.02 points/y), which accounts for nearly 66.4% (95% CI, 85.9% to 43.0%) and 78.9% (95% CI, 102.6% to 55.3%) of changes of MSE and UVA, respectively, among all factors for youths. The greatest MSE shifts occurred in grades 3 and 7 (eg, for the June 2019 census, the RD was -0.26 diopters/y [95% CI, -0.33 to -0.20 diopters/y] for grade 3 and -0.41 diopters/y [95% CI, -0.66 to -0.15 diopters/y] for grade 7).

CONCLUSIONS AND RELEVANCE

These findings suggest that receiving more years of education, instead of age, may be a risk factor associated with myopia progression in youths.

Age- and sex-related differences in the measures of anterior segment parameters in a myopic clinical sample using Pentacam Scheimpflug tomography

PURPOSE

To assess age-and sex-related differences of anterior segment parameters in a myopic clinical sample.

METHODS

This clinic-based retrospective study involved eligible subjects grouped into myopia (i.e., low-to-moderate) and high myopia. Demographics and anterior segment parameters measures were recorded and analyzed.

RESULTS

Some 153 eligible eyes were analyzed-98 myopia and 55 high myopia-comprising 87 males and 66 females. The mean ages and ranges were 28.47 years (SD = 9.59 years), 8-50 years, and 27.82 years (SD = 9.69 years), 10-51 years, for the myopia and the high myopia groups, respectively. The means of the spherical equivalents were - 3.02 D (SD = 1.46 D, range: - 0.50 to - 5.85 D), for the myopia group and - 10.42 D (SD = 5.50 D, range: - 6.00 to - 21.86 D) for the high myopia group. No significant difference was found between degree of myopia and anterior segment measures. Males had larger anterior chamber volume (mean 175.71 ± 26.27, range: 124-225 mm³); (P = 0.007) and deeper anterior chamber depth (3.73 ± 0.27, range: 3.06-4.41 mm) (P = 0.017) than females in the myopia group. Females also had significantly steeper anterior corneal curvature, Km (ant.) but flatter posterior corneal curvature, Km (post.), (- 6.31 ± 0.25, range - 7.00 to - 5.90 D) in both the myopia group [Km (ant.): 44.06 D ± 1.33 D, range: 41.30-47.10; Km (post.): - 6.31 D ± 0.25 D, range: - 7.00 to - 5.90; P = 0.008, P = 0.002, respectively] and the high myopia group [Km (ant.): 43.79 D ± 0.33 D, range: 41.00-47.10; Km (post.): - 6.22 D ± 0.30 D, range: - 6.80 to - 5.60; P = 0.034, P = 0.049, respectively]. Age was not correlated with the anterior segment parameters in both degrees of myopia.

CONCLUSION

Sex has significant influence on the corneal curvature, anterior chamber volume and anterior chamber depth regardless of the degree of myopia.

Myopic choroidal neovascularization: management issues remain

In the modern world, myopia continues to be one of the most common refractive errors and is considered a socially signifi cant problem, since it is a common cause of decreased vision. In connection with the growth of myopia, the risk of developing complications in the fundus increases, leading to the development of degenerative changes in the retina and an irreversible decrease in visual functions in young and middle-aged people. One of these complications is myopic choroidal neovascularization, which leads to a progressive, irreversible decrease in visual acuity and poor prognosis, and the process is often bilateral in nature. The tactics of managing patients with such complications has been determined: antiangiogenic therapy is used – intravitreal therapy with anti-VEGF drugs, which is currently the fi rst choice therapy for this pathology. But in some cases, antiangiogenic therapy is contraindicated, and the question arises about the tactics of managing such patients. The aim: to study treatment options for myopic choroidal neovascularization in patients with myopia in different situations.Material and methods. The paper presents two clinical observations of patients with mChNV, considers the tactics of their management. The patients underwent standard ophthalmological examination, optical coherence tomography (OCT) and OCT-Angio (OPTOPOL Technology, Poland).Conclusions. Women with myopia planning pregnancy need a thorough examination not only by a clinician, but also by an ophthalmologist, since it is necessary to take into account not only the degree of myopia and choose the optimal delivery method, but also to study the state of the retina for the timely diagnosis of degenerative changes in the fundus.

Short-term Comparison of Refractive Errors between Two Different Age Groups after LASEK for Moderate Myopia

Purpose: To investigate the safety of laser epithelial keratomileusis (LASEK) by drawing a comparison between two groups divided according to age (18-19 vs. 20-21 years old).Methods: The study was conducted as a retrospective analysis including 339 patients (678 eyes) who underwent LASEK between January 2017 and April 2020. Patients were divided by age group, group I (18-19 years old) and group II (20-21 years old). The objectives of the study included determination of visual acuity and refractive errors before and at 1, 3, and 6 months after the procedure.Results: The preoperative mean spherical equivalents (SEs) were -4.73 ± 0.88 diopters (D) in group I and -4.58 ± 0.87 D in group II (<i>p</i> = 0.34). At 1 month postoperatively, mean SEs were 0.32 ± 0.46 D in group I and 0.26 ± 0.59 D in group II (<i>p</i> = 0.18). At 3 months postoperatively, the mean SEs were 0.30 ± 0.47 D in group I and 0.28 ± 0.50 D in group II (<i>p</i> = 0.67). At 6 months postoperatively, the mean SEs were 0.15 ± 0.47 D in group I and 0.14 ± 0.50 D in group II (<i>p</i> = 0.89). There were no significant differences in postoperative best corrected visual acuity between group I and group II at 1, 3, or 6 months (<i>p</i> = 0.20, <i>p</i> = 0.13, and <i>p</i> = 0.11, respectively).Conclusions: There were no significant differences in postoperative mean SE or safety of LASEK between moderate myopia patients 18-19 years old and those 20-21 years old.

Adjunctive effects of orthokeratology and atropine 0.01% eye drops on slowing the progression of myopia

CLINICAL RELEVANCE

All eye health care practitioners should know how to control myopia.

BACKGROUND

Investigating the adjunctive effects of orthokeratology and 0.01% atropine eye drops on controlling the progression of myopia in Chinese children.

METHODS

The prospective study included Chinese children aged 8 to 13 years having a spherical equivalent refractive error ranging from -2.00 to -5.00 D. Participants were categorised into two groups: combination group (orthokeratology and 0.01% atropine) or atropine group (0.01% atropine). The axial length and spherical equivalent refraction were measured at baseline and every three months post-treatment and compared over two years.

RESULTS

The combinaion and atropine groups comprised 20 and 22 participants. Following two years of treatment, the average spherical equivalent refraction change was 0.88 ± 0.31 D and 1.14 ± 0.63 D in the combination group and atropine group, respectively (P = 0.026), with an average increment in axial length of 0.50 ± 0.17 mm and 0.61 ± 0.21 mm, respectively (P = 0.091). In the atropine group, increased axial length was positively correlated with baseline spherical equivalent refraction (P = 0.018) and negatively correlated with baseline age (P = 0.003). However, these correlations were not observed in the combination group. In the subgroup of subjects aged 8-10 years and another subgroup of subjects with shorter initial axial length (22.00 to 24.50 mm), the changes in axial length over two years were significantly smaller in the combination group than the atropine group.

CONCLUSION

Orthokeratology and 0.01% atropine eye drops combination therapy were found to be more effective in reducing progression of myopia, as measured through spherical equivalent refraction changes, than atropine monotherapy in children over two years. Combinatorial therapy was more effective in controlling the elongation of axial length in children with younger baseline age or shorter baseline axial length.

Study of the effects of rabbit scleral fibroblasts on cellular biomechanical properties and MMP-2 expression using two modes of riboflavin/ultraviolet A wave collagen cross-linking

OBJECTIVE

The aim of this study is to evaluate the cellular biomechanical properties and MMP-2 expression changes in rabbit scleral fibroblasts using two modes of riboflavin and ultraviolet A (UVA) collagen cross-linking (CXL).

METHODS

Twenty-four New Zealand white rabbits were randomly divided into two groups, A and B. The left eye was chosen for the experimental group and the right eye for the control group. In group A, the eyes were irradiated for 30 min, with a power density of 3.0 mW/cm². In group B, the eyes were irradiated for 9 min, with a power density of 10.0 mW/cm². One week after CXL, full-field electroretinography was performed. Sixty days after CXL, the rabbits were sacrificed, and scleral fibroblasts were extracted from the CXL-treated sclera area and corresponding parts of control sclera and cultured. Cellular biomechanical properties were evaluated using the micropipette aspiration technique, and the MMP-2 protein expression was determined by Western blot analysis.

RESULTS

There was no statistical difference in the amplitude and latency of the dark adaptation 3.0 and light adaptation 3.0 between the CXL and control eyes of groups A and B (P > 0.05). Compared with the control groups, the Young's modulus of the fibroblasts and apparent viscosity of the experimental eyes in groups A and B were increased after CXL (P < 0.05), but there was no significant difference between the two groups under different irradiation modes (P > 0.05). The MMP-2 expression in scleral fibroblasts from experimental eyes was significantly higher than that in scleral fibroblasts from control eyes in groups A and B. Under the two different irradiation modes, the MMP-2 expression in the scleral fibroblasts from experimental eyes in group A was significantly higher than that in the scleral fibroblasts from experimental eyes in group B.

CONCLUSION

The riboflavin-UVA scleral CXL conducted in two different modes produced no significant side effects on the retina and could strengthen the cell biomechanical properties as well as increase the MMP-2 expression of scleral fibroblasts significantly.

Incidence and risk factors for retinal detachment following laser-assisted in-situ keratomileusis

Purpose:

The aim of this work was to study the incidence and potential risk factors for development of retinal detachment (RD) after laser-assisted in situ keratomileusis (LASIK) surgery over a long-term follow-up.

Methods:

This was a retrospective interventional case series. A total of 694 eyes of 352 patients were included who had undergone LASIK surgery at a tertiary eye care institute between January 2005 and September 2015 who had a minimum follow-up of 5 years after the surgery were included. Kaplan–Meier analysis and Cox proportion regression model was used to estimate the potential risk factors and cumulative risk for the development of RD.

Results:

Out of the total patients, 5 eyes developed RD after a mean follow-up of 7 years. The cumulative risk of RD after 1 year was 0.4%, after 2 years was 0.5% and after 7 years was 0.7%. Increased risk of RD was not associated with age at LASIK surgery, gender, laterality, and spherical equivalent (P > 0.05). A significantly increased risk for the development of RD was observed in eyes that were given prior prophylactic laser photocoagulation for peripheral lesions in multivariate cox proportional regression analysis with a hazard ratio (HR) of 9.33 (CI- 1.554-56.094; P = 0.015).

Conclusion:

We emphasize the need for a regular follow-up after the LASIK procedure to ensure timely treatment of any new retinal lesions.

A synopsis of the prevalence rates and environmental risk factors for myopia

The prevalence rates of myopia are higher in urban Asian cities such as Hong Kong and Singapore. One observation over the past few decades is that the prevalence rates of myopia have been rising and there is an epidemic of myopia in Asia. The age-old question of the roles of nature and nurture in this process remains unanswered. The strongest evidence for an environmental link to myopia is near work activity. Childhood exposure to night lighting has also been explored in different studies but the results have been mixed. Twin studies, segregation analysis and association studies have demonstrated that hereditary factors play an important role in myopia development. The exact nature and interplay of genetic and environmental factors is not known and data suggest that environmental factors may interact with genetic factors to increase the risks of developing myopia. Future research is needed to identify specific modifiable lifestyle factors and genetic markers for myopia. This will enable preventive measures such as health education to be instituted.

The biological basis of myopic refractive error

Myopia is among the most common refractive errors and is associated with the greatest risk of pathological outcomes. Most animals, including humans, are born with hyperopic errors. During development, axial elongation of the eye occurs and is regulated through a vision-dependent process, known as emmetropisation The extremely rapid changes in the prevalence of myopia and the dependence of myopia on the level of education indicate that there are very strong environmental impacts on the development of myopia. This conflicts with the common occurrence of familial patterns of inheritance of myopia, which suggests a role for genetic determination. There are more than 150 defined genetic syndromes in which familial high myopia is one of the features, including some that are not associated with other syndromes. The evidence for the roles of both nature and nurture in the aetiology of myopia is discussed. This review also examines the experimentally induced refractive errors associated with form-deprivation, recovery from form deprivation and the effects of both negative and positive lenses. In addition, it looks at the local and optical control of eye growth. Finally, the various control pathways for growth are considered. These include dopamine, ZENK-glucagon, retinoic acid and retinoic acid receptors, crystallin, seratonin and melatonin, vasoactive intestinal peptide and enkephalins, nitric oxide and various growth factors.

Ocular growth and metabolomics are dependent upon the spectral content of ambient white light

Myopia results from an excessive axial growth of the eye, causing abnormal projection of remote images in front of the retina. Without adequate interventions, myopia is forecasted to affect 50% of the world population by 2050. Exposure to outdoor light plays a critical role in preventing myopia in children, possibly through the brightness and blue-shifted spectral composition of sunlight, which lacks in artificial indoor lighting. Here, we evaluated the impact of moderate levels of ambient standard white (SW: 233.1 lux, 3900 K) and blue-enriched white (BEW: 223.8 lux, 9700 K) lights on ocular growth and metabolomics in a chicken-model of form-deprivation myopia. Compared to SW light, BEW light decreased aberrant ocular axial elongation and accelerated recovery from form-deprivation. Furthermore, the metabolomic profiles in the vitreous and retinas of recovering form-deprived eyes were distinct from control eyes and were dependent on the spectral content of ambient light. For instance, exposure to BEW light was associated with deep lipid remodeling and metabolic changes related to energy production, cell proliferation, collagen turnover and nitric oxide metabolism. This study provides new insight on light-dependent modulations in ocular growth and metabolomics. If replicable in humans, our findings open new potential avenues for spectrally-tailored light-therapy strategies for myopia.

Association of refraction and ocular biometry in highly myopic eyes

Clinical relevance: Ocular biometry is key to understanding the determinants of ocular development and pathology changes, especially for the thriving myopic population in Asia. Investigating biometric data in highly myopic eyes within a wide age spectrum is therefore of high importance.Background: To report the magnitude of change in spherical equivalent for each unit of change in the ocular biometry parameters in a highly myopic population in China.Methods: Highly myopic patients aged 7 to 70 years were recruited from the Zhongshan Ophthalmic Center, China. Each patient had a cycloplegic refraction and a measurement of ocular biometry.Results: Data from 823 right eyes were available for analysis, with a mean age of 22.7 years and a median spherical equivalent of -8.88 D. Axial length and lens thickness increased with age, while anterior chamber depth (ACD) decreased in older subjects. There was a significant trend of increasing axial length, lens thickness, vitreous chamber depth (VCD) and decreasing ACD and calculated lens power over spherical equivalent quartiles (all p < 0.001). The univariate linear regression models showed that 1-D change in refraction equalled to a 0.33- to 0.34-mm increase of axial length, and a 0.32 to 0.33-mm increase of VCD in highly myopic eyes. Among the three components of axial length, lens thickness was associated with myopia shift in the groups of 7-18 years and 19-39 years (both p < 0.001), and VCD was significant in all groups (all p < 0.001), while ACD was not significant in any age group.Conclusion: The associations between refraction and axial length were consistent in children, young adults and the elderly with high myopia. Lens thickening with a higher degree of myopia appeared at a very early age, and vitreous chamber depth remained to be a prominent factor of refraction change in highly myopic eyes throughout seven to 70 years of age.

Bayesian Meta-Analysis of Myopia Control with Multifocal Lenses

The aim of this study is to provide reliable guidelines for the mean percentage efficacy together with the 95% credibility interval in slowing down progression of myopia by a specific intervention over defined time periods, derived from a substantial number of randomised controlled clinical trials (RCTs) with consistent outcomes. Multifocal spectacles and contact lenses represent interventions with the largest number of RCTs carried out. Our meta-analyses considered 10 RCTs involving 1662 children which have tested the efficacy of progressive addition spectacle lenses (PALs). In a separate model for comparison purposes nine RCTs with 982 children trialling soft multifocal contact lenses (MFCLs) were analysed. Bayesian random-effects hierarchical models were fitted. The highest efficacy in retarding progression of the scaled sphere equivalent refraction was achieved after 12 M follow-up with the mean 28% reduction in progression and the 95% credibility interval between 21% and 35%. For comparison, the 95% credibility interval for the mean efficacy of soft MFCLs at 12 M follow up is 21% to 37%. We conclude that both multifocal spectacle and contact lenses moderately slow down progression of myopia, relative to single-vision spectacle lenses (SVLs) in the first 12 months after intervention. The relative efficacy of PALs tends to weaken after the first 12 months.

A STROBE-compliant case-control study: Effects of cumulative doses of topical atropine on intraocular pressure and myopia progression

Topical atropine has become a mainstream treatment of myopia throughout East and Southeast Asia, but it is uncertain whether long-term topical atropine therapy induces intraocular pressure (IOP) elevation and subsequent development of glaucoma. We then prospectively examined the effects of long-term atropine treatment on IOP.Our case series collected 186 myopic children who were younger than 16 years of age. Complete ocular examination data, IOP and refractive status measurements beginning in 2008 were collected for all participants. Participants were divided into two groups: 121 children who received atropine therapy at various concentrations were classified as the treated group, whereas 65 children who did not receive atropine therapy were classified as the untreated (reference) group. In the treated group, clinicians prescribed different concentrations of atropine eye drops according to their discretion with regard to the severity of myopia on each visit of the patient. We then calculated the cumulative dose of atropine therapy from 2008 to the patients' last follow-up in 2009. Furthermore, the treated group was then further divided into low- and high-refractive-error groups of nearly equal size for further analysis.There were no significant differences for the baseline refractive errors and IOPs between the treated and untreated groups. Both the low- and high-cumulative atropine dosage subgroups showed significantly lower myopic progression than the untreated group, but there was no significant difference between the two subgroups in terms of different cumulative dosages. All groups, including the untreated group, showed an increase of mean IOP at the last follow-up, but both low- and high-cumulative atropine dosage subgroups experienced a smaller increase of IOP. The mean IOP of all atropine-treated groups showed no significant increase in either low- or high-refractive-error eyes.This study revealed that topical atropine eye drops do not induce ocular hypertension and are effective for slowing the progression of myopia. The treatment effects are not correlated with the cumulative atropine dosages.

[Pharmaceutical aspects of medicated myopia control]

The article presents data on the mechanism of various approaches of drug-induced myopia control and their potential effectiveness, and analyses promising options for medicated correction of myopia.

Evolution of the Prevalence of Myopia among Taiwanese Schoolchildren: A Review of Survey Data from 1983 through 2017

PURPOSE

The aim of this study was to evaluate the changes in the prevalence of myopia in Taiwanese schoolchildren over the past few decades and to analyze the risk factors for myopia.

DESIGN

Analysis of 8 consecutive population-based myopia surveys conducted from 1983 through 2017.

PARTICIPANTS

An average of 8917 (5019-11 656) schoolchildren 3 to 18 years of age were selected using stratified systematic cluster sampling or by probability proportional to size sampling.

METHODS

All participants underwent complete ophthalmic evaluations. Three drops of 0.5% tropicamide were used to obtain the cycloplegic refractive status of each participant. Questionnaires were used to acquire participant data from the 1995, 2005, 2010, and 2016 surveys.

MAIN OUTCOME MEASURES

Prevalence of myopia (spherical equivalence of ≤-0.25 diopter [D]) and high myopia (≤-6.0 D) was assessed. Multivariate analyses of risk factors were conducted.

RESULTS

The prevalence of myopia among all age groups increased steadily. From 1983 through 2017, the weighted prevalence increased from 5.37% (95% confidence interval [CI], 3.50%-7.23%) to 25.41% (95% CI, 21.27%-29.55%) for 7-year-olds (P = 0.001 for trend) and from 30.66% (95% CI, 26.89%-34.43%) to 76.67% (95% CI, 72.94%-80.40%) for 12-year-olds (P = 0.001 for trend). The prevalence of high myopia also increased from 1.39% (95% CI, 0.43%-2.35%) to 4.26% (95% CI, 3.35%-5.17%) for 12-year-olds (P = 0.008 for trend) and from 4.37% (95% CI, 2.91%-5.82%) to 15.36% (95% CI, 13.78%-16.94%) for 15-year-olds (P = 0.039 for trend). In both the 2005 and 2016 survey samples, children who spent less than 180 minutes daily on near-work activities showed significantly lower risks for myopia developing (<60 minutes: odds ratio [OR], 0.48 and 0.56; 60-180 minutes: OR, 0.69 and 0.67). In the 2016 survey, spending more than 60 minutes daily on electronic devices was associated significantly with both myopia and high myopia (OR, 2.43 and 2.31).

CONCLUSIONS

The prevalence of myopia among schoolchildren increased rapidly from 1983 through 2017 in Taiwan. The major risk factors are older age and time spent on near-work activities. Use of electronic devices increased the amount of time spent on near-work and may increase the risk of developing myopia.

Cross-Sectional Analysis of University Students' Health Using a Digitised Health Survey

University student years are a particularly influential period, during which time students may adopt negative behaviours that set the precedent for health outcomes in later years. This study utilised a newly digitised health survey implemented during health screening at a university in Singapore to capture student health data. The aim of this study was to analyze the health status of this Asian university student population. A total of 535 students were included in the cohort, and a cross-sectional analysis of student health was completed. Areas of concern were highlighted in student’s body weight, visual acuity, and binge drinking. A large proportion of students were underweight (body mass index (BMI) < 18.5)—18.9% of females and 10.6% of males—and 7% of males were obese (BMI > 30). Although the overall prevalence of alcohol use was low in this study population, 9% of females and 8% of males who consumed alcohol had hazardous drinking habits. Around 16% of these students (male and female combined) typically drank 3–4 alcoholic drinks each occasion. The prevalence of mental health conditions reported was very low (<1%). This study evaluated the results from a digitised health survey implemented into student health screening to capture a comprehensive health history. The results reveal potential student health concerns and offer the opportunity to provide more targeted student health campaigns to address these.

Myopia and Regional Variations in Retinal Thickness in Healthy Eyes

Purpose

To investigate the effects of refraction on retinal thickness measurements at different locations and layers in healthy eyes of Saudi participants.

Methods

Thirty-six randomly selected adults aged 27.0 ± 5.7 years who attended a Riyadh hospital from 2016 to 2017 were categorized into three groups: non-myopic (spherical equivalent refraction [SER], +1.00 to –0.50 diopters [D]), low myopic (SER, –0.75 to –3.00D), and moderate to high myopic (SER ≤ –3.25D). Full, inner, and outer retinal thicknesses were measured at nine locations by spectral-domain stratus optical coherence tomography (Optovue Inc., Fremont, CA, USA) and were compared according to refractive group and sex.

Results

The mean SERs for the non-myopia, low myopia, and moderate to high myopia groups were 0.2 ± 0.6, –1.5 ± 0.5, and –7.5 ± 1.9 D, respectively. Refractive error, but not sex, had significant effects on the retinal layer thickness measurements at different locations (P < 0.05). The parafoveal and outer retinal layers were significantly thicker than the perifoveal and inner retina layers in all groups (P < 0.05). The full foveal thickness was higher and the full parafoveal and perifoveal regions were thinner in moderate to high myopic eyes than in the non-myopic eyes (P < 0.05), but were similar to those in the low myopic eyes (P > 0.05). The foveal thicknesses measured in the inner and outer layers of the retina were higher but the thicknesses measured at the inner and outer layers of the parafoveal and perifoveal regions were lower in moderate to high myopic eyes.

Conclusion

There were regional differences in the retinal layer thicknesses of healthy Saudi eyes, which was dependent on the central refractions. This is important when interpreting retinal nerve fiber layer thicknesses in myopia and disease management in Saudi participants.

Glaucoma assessment in high myopic eyes using optical coherence tomography with long axial length normative database

BACKGROUND

We investigated the performance of glaucoma assessment using RS-3000 spectral domain optical coherence tomography with a long axial length (AL) normative database versus Cirrus HD-OCT in eyes with high myopia.

METHODS

This is a prospective case-control study. Eyes with AL ≥26 mm were enrolled, including 40 control eyes and 41 eyes with primary open-angle glaucoma. Each participant received OCT imaging with both devices at the same visit. We calculated the area under receiver operating characteristic curve (AUROC) for circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (GCC) parameters, and compared the false-positive and false-negative rates between the two devices.

RESULTS

Both devices performed comparably well in glaucoma assessment regarding cpRNFL parameters, with the best parameter being the average cpRNFL for RS-3000 (AUROC: 0.899) and the clock-hour 7 cpRNFL for Cirrus HD (AUROC: 0.912). Regarding macular GCC parameters, although the nasal-inferior outer sector of the RS-3000 (AUROC 0.873) and the inferior-temporal sector of the Cirrus HD (AUROC 0.840) performed well in glaucoma assessment, generally speaking there was a higher false-positive rate using Cirrus HD when compared with that of RS-3000.

CONCLUSION

For eyes with long AL, both OCT devices are comparable in the ability of discriminating glaucoma from non-glaucoma in terms of cpRNFL parameters, while the macular GCC parameters of RS-3000 were less likely to over-diagnose glaucoma in highly myopic eyes.

Sex-Specific Differences in Circumpapillary Retinal Nerve Fiber Layer Thickness

PURPOSE

To investigate the role of sex on retinal nerve fiber layer (RNFL) thickness at 768 circumpapillary locations based on OCT findings.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

We investigated 5646 eyes of 5646 healthy participants from the Leipzig Research Centre for Civilization Diseases (LIFE)-Adult Study of a predominantly white population.

METHODS

All participants underwent standardized systemic assessments and ocular imaging. Circumpapillary RNFL (cRNFL) thickness was measured at 768 points equidistant from the optic nerve head using spectral-domain OCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). To control ocular magnification effects, the true scanning radius was estimated by scanning focus. Student t test was used to evaluate sex differences in cRNFL thickness globally and at each of the 768 locations. Multivariable linear regression and analysis of variance were used to evaluate individual contributions of various factors to cRNFL thickness variance.

MAIN OUTCOME MEASURES

Difference in cRNFL thickness between males and females.

RESULTS

Our population consisted of 54.8% females. The global cRNFL thickness was 1 μm thicker in females (P < 0.001). However, detailed analysis at each of the 768 locations revealed substantial location specificity of the sex effects, with RNFL thickness difference ranging from -9.98 to +8.00 μm. Females showed significantly thicker RNFLs in the temporal, superotemporal, nasal, inferonasal, and inferotemporal regions (43.6% of 768 locations), whereas males showed significantly thicker RNFLs in the superior region (13.2%). The results were similar after adjusting for age, body height, and scanning radius. The superotemporal and inferotemporal RNFL peaks shifted temporally in females by 2.4° and 1.9°, respectively. On regions with significant sex effects, sex explained more RNFL thickness variance than age, whereas the major peak locations and interpeak angle explained most of the RNFL thickness variance unexplained by sex.

CONCLUSIONS

Substantial sex effects on cRNFL thickness were found at 56.8% of all 768 circumpapillary locations, with specific patterns for different sectors. Over large regions, sex was at least as important in explaining the cRNFL thickness variance as was age, which is well established to have a substantial impact on cRNFL thickness. Including sex in the cRNFL thickness norm could therefore improve glaucoma diagnosis and monitoring.

A 3-year Randomized Clinical Trial of MiSight Lenses for Myopia Control

SIGNIFICANCE

Results of this randomized, double-masked clinical trial demonstrate the effectiveness of the MiSight soft contact lens in slowing myopia progression over multiple years.

PURPOSE

The purpose of this study was to quantify the effectiveness of MiSight daily disposable soft contact lens in slowing the progression of juvenile-onset myopia.

METHODS

Myopic children (spherical equivalent refraction, -0.75 to -4.00 D; astigmatism, <1.00 D) aged 8 to 12 years with no prior contact lens experience were enrolled in a 3-year, double-masked, randomized clinical trial at four investigational sites in four countries. Subjects in each group were matched for age, sex, and ethnicity and were randomized to either a MiSight 1-day contact lens (test) or Proclear 1-day (control; omafilcon A) and worn on a daily disposable basis. Primary outcome measures were the change in cycloplegic spherical equivalent refraction and axial length.

RESULTS

Of the subjects enrolled, 75.5% (109/144) completed the clinical trial (53 test, 56 control). Unadjusted change in spherical equivalent refraction was -0.73 D (59%) less in the test group than in the control group (-0.51 ± 0.64 vs. -1.24 ± 0.61 D, P < .001). Mean change in axial length was 0.32 mm (52%) less in the test group than in the control group (0.30 ± 0.27 vs. 0.62 ± 0.30 mm, P < .001). Changes in spherical equivalent refraction and axial length were highly correlated (r = -0.90, P < .001). Over the course of the study, there were no cases of serious ocular adverse events reported. Four asymptomatic corneal infiltrative (one test, three control) events were observed at scheduled study visits.

CONCLUSIONS

Results of this clinical trial demonstrate the effectiveness of the MiSight daily disposable soft contact lens in slowing change in spherical equivalent refraction and axial length.

Evidence That Emmetropization Buffers Against Both Genetic and Environmental Risk Factors for Myopia

Purpose

To test the hypothesis that emmetropization buffers against genetic and environmental risk factors for myopia by investigating whether risk factor effect sizes vary depending on children's position in the refractive error distribution.

Methods

Refractive error was assessed in participants from two birth cohorts: Avon Longitudinal Study of Parents and Children (ALSPAC) (noncycloplegic autorefraction) and Generation R (cycloplegic autorefraction). A genetic risk score for myopia was calculated from genotypes at 146 loci. Time spent reading, time outdoors, and parental myopia were ascertained from parent-completed questionnaires. Risk factors were coded as binary variables (0 = low, 1 = high risk). Associations between refractive error and each risk factor were estimated using either ordinary least squares (OLS) regression or quantile regression.

Results

Quantile regression: effects associated with all risk factors (genetic risk, parental myopia, high time spent reading, low time outdoors) were larger for children in the extremes of the refractive error distribution than for emmetropes and low ametropes in the center of the distribution. For example, the effect associated with having a myopic parent for children in quantile 0.05 vs. 0.50 was as follows: ALSPAC: age 15, -1.19 D (95% CI -1.75 to -0.63) vs. -0.13 D (-0.19 to -0.06), P = 0.001; Generation R: age 9, -1.31 D (-1.80 to -0.82) vs. -0.19 D (-0.26 to -0.11), P < 0.001. Effect sizes for OLS regression were intermediate to those for quantiles 0.05 and 0.50.

Conclusions

Risk factors for myopia were associated with much larger effects in children in the extremes of the refractive error distribution, providing indirect evidence that emmetropization buffers against both genetic and environmental risk factors.

Interventions to slow progression of myopia in children

BACKGROUND

Nearsightedness (myopia) causes blurry vision when one is looking at distant objects. Interventions to slow the progression of myopia in children include multifocal spectacles, contact lenses, and pharmaceutical agents.

OBJECTIVES

To assess the effects of interventions, including spectacles, contact lenses, and pharmaceutical agents in slowing myopia progression in children.

SEARCH METHODS

We searched CENTRAL; Ovid MEDLINE; Embase.com; PubMed; the LILACS Database; and two trial registrations up to February 2018. A top up search was done in February 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs). We excluded studies when most participants were older than 18 years at baseline. We also excluded studies when participants had less than -0.25 diopters (D) spherical equivalent myopia.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods.

MAIN RESULTS

We included 41 studies (6772 participants). Twenty-one studies contributed data to at least one meta-analysis. Interventions included spectacles, contact lenses, pharmaceutical agents, and combination treatments. Most studies were conducted in Asia or in the United States. Except one, all studies included children 18 years or younger. Many studies were at high risk of performance and attrition bias. Spectacle lenses: undercorrection of myopia increased myopia progression slightly in two studies; children whose vision was undercorrected progressed on average -0.15 D (95% confidence interval [CI] -0.29 to 0.00; n = 142; low-certainty evidence) more than those wearing fully corrected single vision lenses (SVLs). In one study, axial length increased 0.05 mm (95% CI -0.01 to 0.11) more in the undercorrected group than in the fully corrected group (n = 94; low-certainty evidence). Multifocal lenses (bifocal spectacles or progressive addition lenses) yielded small effect in slowing myopia progression; children wearing multifocal lenses progressed on average 0.14 D (95% CI 0.08 to 0.21; n = 1463; moderate-certainty evidence) less than children wearing SVLs. In four studies, axial elongation was less for multifocal lens wearers than for SVL wearers (-0.06 mm, 95% CI -0.09 to -0.04; n = 896; moderate-certainty evidence). Three studies evaluating different peripheral plus spectacle lenses versus SVLs reported inconsistent results for refractive error and axial length outcomes (n = 597; low-certainty evidence). Contact lenses: there may be little or no difference between vision of children wearing bifocal soft contact lenses (SCLs) and children wearing single vision SCLs (mean difference (MD) 0.20D, 95% CI -0.06 to 0.47; n = 300; low-certainty evidence). Axial elongation was less for bifocal SCL wearers than for single vision SCL wearers (MD -0.11 mm, 95% CI -0.14 to -0.08; n = 300; low-certainty evidence). Two studies investigating rigid gas permeable contact lenses (RGPCLs) showed inconsistent results in myopia progression; these two studies also found no evidence of difference in axial elongation (MD 0.02mm, 95% CI -0.05 to 0.10; n = 415; very low-certainty evidence). Orthokeratology contact lenses were more effective than SVLs in slowing axial elongation (MD -0.28 mm, 95% CI -0.38 to -0.19; n = 106; moderate-certainty evidence). Two studies comparing spherical aberration SCLs with single vision SCLs reported no difference in myopia progression nor in axial length (n = 209; low-certainty evidence). Pharmaceutical agents: at one year, children receiving atropine eye drops (3 studies; n = 629), pirenzepine gel (2 studies; n = 326), or cyclopentolate eye drops (1 study; n = 64) showed significantly less myopic progression compared with children receiving placebo: MD 1.00 D (95% CI 0.93 to 1.07), 0.31 D (95% CI 0.17 to 0.44), and 0.34 (95% CI 0.08 to 0.60), respectively (moderate-certainty evidence). Axial elongation was less for children treated with atropine (MD -0.35 mm, 95% CI -0.38 to -0.31; n = 502) and pirenzepine (MD -0.13 mm, 95% CI -0.14 to -0.12; n = 326) than for those treated with placebo (moderate-certainty evidence) in two studies. Another study showed favorable results for three different doses of atropine eye drops compared with tropicamide eye drops (MD 0.78 D, 95% CI 0.49 to 1.07 for 0.1% atropine; MD 0.81 D, 95% CI 0.57 to 1.05 for 0.25% atropine; and MD 1.01 D, 95% CI 0.74 to 1.28 for 0.5% atropine; n = 196; low-certainty evidence) but did not report axial length. Systemic 7-methylxanthine had little to no effect on myopic progression (MD 0.07 D, 95% CI -0.09 to 0.24) nor on axial elongation (MD -0.03 mm, 95% CI -0.10 to 0.03) compared with placebo in one study (n = 77; moderate-certainty evidence). One study did not find slowed myopia progression when comparing timolol eye drops with no drops (MD -0.05 D, 95% CI -0.21 to 0.11; n = 95; low-certainty evidence). Combinations of interventions: two studies found that children treated with atropine plus multifocal spectacles progressed 0.78 D (95% CI 0.54 to 1.02) less than children treated with placebo plus SVLs (n = 191; moderate-certainty evidence). One study reported -0.37 mm (95% CI -0.47 to -0.27) axial elongation for atropine and multifocal spectacles when compared with placebo plus SVLs (n = 127; moderate-certainty evidence). Compared with children treated with cyclopentolate plus SVLs, those treated with atropine plus multifocal spectacles progressed 0.36 D less (95% CI 0.11 to 0.61; n = 64; moderate-certainty evidence). Bifocal spectacles showed small or negligible effect compared with SVLs plus timolol drops in one study (MD 0.19 D, 95% CI 0.06 to 0.32; n = 97; moderate-certainty evidence). One study comparing tropicamide plus bifocal spectacles versus SVLs reported no statistically significant differences between groups without quantitative results. No serious adverse events were reported across all interventions. Participants receiving antimuscarinic topical medications were more likely to experience accommodation difficulties (Risk Ratio [RR] 9.05, 95% CI 4.09 to 20.01) and papillae and follicles (RR 3.22, 95% CI 2.11 to 4.90) than participants receiving placebo (n=387; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Antimuscarinic topical medication is effective in slowing myopia progression in children. Multifocal lenses, either spectacles or contact lenses, may also confer a small benefit. Orthokeratology contact lenses, although not intended to modify refractive error, were more effective than SVLs in slowing axial elongation. We found only low or very low-certainty evidence to support RGPCLs and sperical aberration SCLs.

Contrast sensitivity and visual acuity in subjects wearing multifocal contact lenses with high additions designed for myopia progression control

OBJECTIVES

To assess the visual performance of multifocal contact lenses (MFCLs) with high addition powers designed for myopia control.

METHODS

Twenty-four non-presbyopic adults (mean age 24 years, range 18-36 years) were fitted with soft MFCLs with add powers of +2.0 D (Add2) and +4.0 D (Add4) (RELAX, SwissLens) and single vision lenses (SVCL; Add0) in a counterbalanced order. In this double-masked study, half of the participants were randomly fitted with 3 mm-distance central zone MFCLs while the other half received 4.5 mm-distance central zone MFCLs. Visual acuity was measured at distance (3.0 m) and at near (0.4 m). Central and peripheral contrast sensitivity was evaluated at distance using the Gabor patch test. The area under the logarithmic contrast sensitivity function curve (ALCSF) was calculated and compared between the groups (i.e. different additions powers used).

RESULTS

Near and distance visual acuities were not affected by the lenses, neither Add2 nor Add4, when compared to Add0, however, CZ3 significantly reduced distance visual acuity with Add4 when compared to CZ4.5 (-0.08 logMAR vs. for CZ3 and -0.18 logMAR for CZ4.5, p = 0.013). MFCLs impaired central ALCSF only when Add2 was used (15.99 logCS for Add2 and 16.36 logCS for SVCLs, p = 0.021). Peripheral ALCSF was statistically lower for both addition powers of the MFCLs when compared to SVCLs (12.70 for Add2 and Add4, 13.73 for SVCLs, p = 0.009). The above effects were the same for both central zones used.

CONCLUSIONS

MFCLs with CZ3 diameter and high add power (Add4) slightly reduced distance visual acuity when compared to CZ4.5 but no reduction in this parameter was found with medium add power (Add2). Central contrast sensitivity was impaired only by MFCLs with the lower add power (Add2). Both add powers in the MFCLs reduced peripheral contrast sensitivity to a similar extent.

Regional changes in the elastic properties of myopic Guinea pig sclera

Biomechanical changes in the sclera likely underlie the excessive eye elongation of axial myopia. We studied the biomechanical characteristics of myopic sclera at the microscopic level using scanning acoustic microscopy (SAM) with 7-μm in-plane resolution. Guinea pigs underwent form-deprivation (FD) in one eye from 4 to 12 days of age to induce myopia, and 12-μm-thick scleral cryosections were scanned using a custom-made SAM. Two-dimensional maps of the bulk modulus (K) and mass density (ρ) were derived from the SAM data using a frequency-domain approach. We assessed the effect on K and ρ exerted by: 1) level of induced myopia, 2) region (superior, inferior, nasal or temporal) and 3) eccentricity from the nerve using univariate and multivariate regression analyses. Induced myopia ranged between -3D and -9.3D (Mean intraocular difference of -6.2 ± 1.7D, N = 11). K decreased by 0.036 GPa for every 1.0 D increase in induced myopia across vertical sections (p < 0.001). Among induced myopia right eyes, K values in the inherently more myopic superior region were 0.088 GPa less than the inferior region (p = 0.002) and K in the proximal nasal region containing the central axis were 0.10 GPa less than temporal K (p = 0.036). K also increased 0.12 GPa for every 1 mm increase in superior vertical distance (p < 0.001), an effect that was blunted after 1 week of FD. Overall, trends for ρ were less apparent than for K. ρ values increased by 20.7 mg/cm3 for every 1.00 D increase in induced myopia across horizontal sections (p < 0.001), and were greatest in the region containing the central posterior pole. ρ values in the inherently more myopic superior region were 13.1 mg/cm3 greater than that found in inferior regions among control eyes (p = 0.002), and increased by 11.2 mg/cm3 for every 1 mm increase in vertical distance (p = 0.001). This peripheral increase in ρ was blunted after 1 week of FD. Scleral material properties vary depending on the location in the sclera and the level of induced myopia. Bulk modulus was most reduced in the most myopic regions (both induced myopia and inherent regional myopia), and suggests that FD causes microscopic local decreases in sclera stiffness, while scleral mass density was most increased in the most myopic regions.

Refractive Error in Chinese Preschool Children: The Shanghai Study

Purpose:

To examine the prevalence of refractive error and some associated factors in Chinese preschool children.

Methods:

The Jinshan District Eye Study was a school-based survey of eye health in a large sample of 4- to 6-year-olds attending kindergartens from May 2013 to December 2013 in Shanghai. Refractive error was measured using an autorefractor under noncycloplegic conditions. Axial length (AL) was measured with an ocular biometry system. In addition, body height and weight were also recorded.

Results:

A total of 7,166 children successfully completed their refraction measurements. The median (interquartile range) of spherical equivalent (SE) for all the children was +0.25 D (−0.13 D to +0.62 D), and the range was −15.88 to +18.13 D. The mean AL for all the children was 22.35±0.70 mm, and the range was 18.20 to 27.71 mm. The overall prevalence of myopia (−1.00 D or less), hyperopia (+2.00 D or greater), and astigmatism (1.00 D or greater) were 5.9%, 1.0%, and 12.7%, respectively. After multivariate analysis, more myopic SE (or less hyperopic SE) was significantly associated with girls, longer AL, taller, and lighter.

Conclusion:

Shanghai has a high prevalence of refractive error in the world. However, longitudinal studies are needed to evaluate refractive changes over time in individual children and warranted to prevent the development of myopia.

Effects of low and moderate refractive errors on chromatic pupillometry

Chromatic pupillometry is an emerging modality in the assessment of retinal and optic nerve disorders. Herein, we evaluate the effect of low and moderate refractive errors on pupillary responses to blue- and red-light stimuli in a healthy older population. This study included 139 participants (≥50 years) grouped by refractive error: moderate myopes (>−6.0D and ≤−3.0D, n = 24), low myopes (>−3.0D and <−0.5D, n = 30), emmetropes (≥−0.5D and ≤0.5D, n = 31) and hyperopes (>0.5D and <6.0D, n = 54). Participants were exposed to logarithmically ramping-up blue (462 nm) and red (638 nm) light stimuli, designed to sequentially activate rods, cones and intrinsically-photosensitive retinal ganglion cells. Pupil size was assessed monocularly using infra-red pupillography. Baseline pupil diameter correlated inversely with spherical equivalent (R = −0.26, P < 0.01), and positively with axial length (R = 0.37, P < 0.01) and anterior chamber depth (R = 0.43, P < 0.01). Baseline-adjusted pupillary constriction amplitudes to blue light did not differ between groups (P = 0.45), while constriction amplitudes to red light were greater in hyperopes compared to emmetropes (P = 0.04) at moderate to bright light intensities (12.25–14.0 Log photons/cm²/s). Our results demonstrate that low and moderate myopia do not alter pupillary responses to ramping-up blue- and red-light stimuli in healthy older individuals. Conversely, pupillary responses to red light should be interpreted cautiously in hyperopic eyes.

Aniseikonia and anisometropia: implications for suppression and amblyopia

Aniseikonia is a difference in the perceived size or shape of images between eyes, and can arise from a variety of physiological, neurological, retinal, and optical causes. Aniseikonia is associated with anisometropia, as both anisometropia itself and the optical correction for anisometropia can cause aniseikonia. Image size differences above one to three per cent can be clinically symptomatic. Common symptoms include asthenopia, headache and diplopia in vertical gaze. Size differences of three and more impair binocular visual functions such as binocular summation and stereopsis. Above five per cent of aniseikonia, binocular inhibition or suppression tend to occur to prevent diplopia and confusion. Aniseikonia can be measured using a range of techniques and can be corrected or reduced by prescribing contact lenses or specially designed spectacle lenses. Subjective testing of aniseikonia is the only way to accurately measure the overall perceived amount of aniseikonia. However, currently it is not routinely assessed in most clinical settings. At least two-thirds of patients with amblyopia have anisometropia, thus we may expect aniseikonia to be common in patients with anisometropic amblyopia. However, aniseikonia may not be experienced by the patient under normal binocular viewing conditions if the image from the amblyopic eye is of poor quality or is too strongly suppressed for image size differences to be recognised. This lack of binocular simultaneous perception in amblyopia may also prevent the measurement of aniseikonia, as most common techniques require direct comparisons of images seen by each eye. Current guidelines for the treatment of amblyopia advocate full correction of anisometropia to equalise image clarity, but do not address aniseikonia. Significant image size differences between eyes may lead to suppression and abnormal binocular adaptations. It is possible that correcting anisometropia and aniseikonia simultaneously, particularly at the initial diagnosis of anisometropia, would reduce the need to develop suppression and improve treatment outcomes for anisometropic amblyopia.

[Rehabilitation methods for individuals with functional vision disorders]

PURPOSE

To develop a rehabilitation system for people with functional vision disorders.

MATERIAL AND METHODS

The study included 56 schoolchildren with functional visual impairments aged 8-17 years, among which 7 had spasm of accommodation, and 49 - paralysis or paresis of accommodation. The examination included visometry, refractometry, ophthalmometry, measurement of the axial eye length, absolute and relative accommodation parameters, fusional reserves, as well as character of binocular vision and asthenopic complaints.

RESULTS

The patients with spasms, pareses and paralyses of accommodation were revealed to have decreased visual acuity, absence or sharp decrease in absolute and relative accommodation, fusional reserves, and simultaneous vision. A method for treating such patients has been developed, which aims for improvement of the blood supply to the ciliary muscle, accommodation reflex, visual acuity and differential sensitivity of the retina, vergence and version accommodation tonicity, convergence and fusion ability. The treatment led to normalization of absolute and relative accommodation, and increase of fusional reserves. The character of vision became binocular, asthenopic complaints stopped. The 'anlauf' glasses allow long-term preservation of the effect of received treatment, as well as prevention of visual disturbances in eye-straining work.

CONCLUSION

The complex approach to the treatment of patients with spasms, pareses and paralyses of accommodation leads to restoration of the functions of visual analyzer in fairly short time (15-20 sessions).

Four-year change in ocular biometric components and refraction in schoolchildren: A cohort study

Purpose

To determine 4-year changes of ocular biometric and dioptric components in Iranian children aged 7-11 years following the first phase.

Methods

468 children were evaluated in the first phase of the study in 2012 and again in 2016-2017. Multi-stage stratified cluster sampling was applied to select the participants. The Topcon autorefractometer and the LENSTAR/BioGraph biometer (WaveLight AG, Erlangen, Germany) were used for cycloplegic refraction and biometry, respectively. All measurements were repeated at 4 years as the baseline assessments.

Results

Of 468 children, 251 (53.6%) were boys. Spherical equivalent (SE) showed a marked myopic shift (P = 0.000) in the second phase which was significantly higher in boys (0.24 vs. 0.18 D) (P < 0.001). Axial length (AL) and anterior chamber depth (ACD) increased by 0.49 ± 0.05 and 0.12 ± 0.02 mm, while lens thickness (LT) and lens power (LP) decreased by 0.08 ± 0.01 mm and 1.59 ± 0.12 D, respectively (P < 0.05). The mean corneal curvature and thickness did not change significantly during 4 years. All biometric component changes were greater in boys. Biometric changes in different age groups showed a decreased LP, increased AL, and increased ACD in most age groups (P < 0.05), while LT and SE did not change significantly in the age groups 9 and 11 years and 8 and 9 years, respectively. Changes in the corneal thickness, diameter, curvature, and refractive astigmatism were not significant in any of the age groups (P > 0.05).

Conclusions

Statistical and clinical changes were seen in AL, ACD, LP, and LT. The changes observed in biometric components (AL, ACD, and LT) had a sinus rhythm.

Prevalence of Myopia among Children Attending Pediatrics Ophthalmology Clinic at Ohud Hospital, Medina, Saudi Arabia

Introduction

Around half of the visually impaired population has uncorrected refractive errors (URE), and myopia constitutes a high proportion of them. URE should be screened and treated early to prevent long-term complications. The aim of this study was to determine the prevalence of myopia among all patients attending a pediatric outpatient clinic at Ohud Hospital in Medina, Saudi Arabia (KSA).

Method

This study was conducted using a convenience sample of all patients attending the clinic (1500 patients) aged between 3 and 14 years, and they were enrolled in the study during the period from May 2017 until September 2017.

Result

Of 1215 subjects, only 43 (3.54%) were diagnosed with myopia. Out of the study participants, 56.8% were female and the mean age was 9.7 ± 3.6. Myopia was more prevalent in male participants than female participants (n = 525, 4%, n = 690, 3.1%, p=0.5). Low myopia was the most common form among the screened individuals. The level of myopia was associated with the degree of the strabismus angle. Approximately 22% of patients with myopia had >25° strabismus angle. There was a statistically significant association with both near work indoor and outdoor activities on weekends and the level of myopia.

Conclusion

The prevalence of myopia among pediatrics patients in Medina is 3.54%. We hope that the results of this study will contribute to a better understanding of this public health issue in Saudi Arabia in order to implant a strict screening program for early detection and interventions to reduce the risk of further progression of visual impairment.

The diluted atropine for inhibition of myopia progression in Korean children

AIM

To evaluate the efficacy and safety of three different concentrations of diluted atropine for the control of myopia in Korean children, and to assess the risk factors associated with rapid myopia progression.

METHODS

A total of 285 children, with refractive errors within the range of -6 diopters (D) between 5 and 14 years of age were included. After using 0.01%, or 0.025%, or 0.05% atropine, for about 1y, changes in refraction, axial lengths and frequency of adverse events were analyzed. Logistic regression analyses were performed to evaluate the risk factors associated with rapid myopia progression.

RESULTS

The changes in the mean spherical equivalent values were -0.134 D/mo in the before atropine group, -0.070 D/mo in the 0.01% atropine group, -0.047 D/mo in the 0.025% atropine group, and -0.019 D/mo in the 0.05% atropine group, with significant differences between the groups (P<0.001). The axial elongation was 0.046 mm/mo, 0.037 mm/mo, 0.025 mm/mo, and 0.019 mm/mo respectively, with significant differences between the groups (P=0.003). The incidence of photophobia and near vision difficulty was not different among the three atropine groups (P=0.425 and P=0.356, respectively). Multivariate logistic regression analyses showed that only highly myopic parents were a significant predictive factor of rapid myopia progression in Korean children (odds ratio, 8.155; 95% confidence interval, 3.626-18.342; P<0.001).

CONCLUSION

Treatment with 0.01%, 0.025% and 0.05% atropine solution inhibits myopia progression in Korean children in a dose-dependent manner. Children with highly myopic parents preferentially shows a rapid myopia progression rate.

[Atropine use for the prevention of myopia progression]

Given the prevalence of myopic refraction (from 50 to 84% in Asian countries and 35 to 49% in European countries and the United States in young people), the development of methods for monitoring and preventing myopia continues to be an urgent task. One of the directions of pharmacological intervention on the progression of myopia is associated with the use of a non-selective M-cholinoreceptors antagonist - atropine. The review presents the results of studies on various aspects of the potential for topical application of atropine to control the progression of myopia (experimental and clinical data on the mechanism of action, the effectiveness of clinical use, the possible side effects of various concentrations of the drug).The heterogeneity of the data presented does not yet lead to the conclusion that the long-term instillations of atropine are effective in prevention of progressive myopia. In addition, the wide application of this method, for example, in the territory of the Russian Federation, is limited by approved official instruction for the local application of the atropine solution in ophthalmology.

The Prevalence and Severity of Myopia among Suburban Schoolchildren in Taiwan

Introduction: We aimed to determine the prevalence and severity of   myopia in suburban schoolchildren. The refractive error, best corrected visual acuity (BCVA) and other ocular indices of 6069 schoolchildren (aged 6 to 15 years) from elementary and junior high schools in Chiayi County, Taiwan were examined in 2013-2015. Materials and Methods: Spherical equivalent (SE) was stratified into 4 categories: emmetropia, mild myopia, moderate myopia, and high myopia for underlying analysis. Chi-squared (χ2) tests were used to determine significant associations between myopia and BCVA and age levels. To compare statistical significance among different age levels, P values of Bonferroni tests were calculated. Receiver operating characteristic (ROC) curves and correlation coefficient were calculated to assess the correlation between myopia and each ocular index. Results: The youngest subject diagnosed with myopia was a 7-year-old. Myopia had significant associations with both BCVA and age levels (95% confidence intervals [CI] = 2.553, 2.713 and -0.284, -0.248, respectively), under P <0.05. Among the calculated ROC values, BCVA had the highest area of 0.676 with myopia. This further confirmed that BCVA was highly correlated with myopia in schoolchildren. Other ocular indices like intraocular pressure (IOP), pupil distance, ocular alignments, or ocular height had ROC curves below 0.5 to myopia. Conclusion: This study concluded that the onset of myopia started earlier and progressively worsened with years of investigation among the suburban schoolchildren. Myopia had significant associations with BCVA and age levels. To effectively reduce the prevalence and severity of myopia, it is time to take actions on eye care education for suburban schoolchildren. Key words: Mean refractive index, Ocular condition, Visual acuity

Short term effect of choroid thickness in the horizontal meridian detected by spectral domain optical coherence tomography in myopic children after orthokeratology

AIM

To investigate choroidal thickness changes in the horizontal meridian after orthokeratology.

METHODS

This is a prospective cross-sectional observed study. Subjects (n=30; 11.3±1.7y) with low-to-moderate myopia (-1.0 to -6.0 diopters), wore orthokeratology (Ortho-K) lenses for 3mo. Before and after Ortho-K, OCT scans were made through the fovea in the horizontal meridian. Choroid thickness around the fovea was acquired by custom software. The analyzed regions along the horizontal meridian were divided into 7 equal zones. Ocular parameters were measured by Lenstar LS 900 non-contact biometry.

RESULTS

Only the right eye ocular parameters were analyzed in this study. Before Ortho-K, choroidal thickness along the horizontal meridian was 273.7±31.8 µm in the temporal zone, 253.1±38.6 µm in the macula zone, and 194.8±52.2 µm in the nasal zone. After Ortho-K, the choroid was thicker in each horizontal zone (P<0.05). The increased thickness was greatest in the temporal zone (13.5±22.5 µm) and least in the nasal zone (8.4±14.2 µm). The axial length (AL) increased 0.02 mm (P>0.05). The choroid thickness change in each horizontal zone was negatively correlated with AL (r, -0.3 to -0.4; P<0.05) except one of the nasal zones.

CONCLUSION

In myopic children, the thickness of the choroid is greatest in the temporal zone and thinnest in the nasal zone. After nightly Ortho-K for 3mo, the thickness increase along the horizontal meridian. The choroid thickness changes are negatively correlated with the change of AL.