Prevalence of myopia in local and international schools in Hong Kong

Cognitive workload affects ocular accommodation and pupillary response

SIGNIFICANCE

Cognitive involvement in reading causes variations in the tonus of autonomic nerve system. The aim of this study was to examine the effect of short-term cognitive load on accommodation and pupils' absolute values and temporal variability in test persons performing three different types of tasks.

PURPOSE

We aimed to show how cognitive tasks of different type and difficulty level affect accommodation and pupil behavior during a short time interval.

METHODS

Participants (n = 58; mean age 16.4 years, SD = 0.56) performed reading from a 10-inch LCD screen placed at 40 cm distance. Three different types of tasks (numerical, textual, and the Stroop task), each at three different levels of cognitive load were introduced. Participants had 90 s to complete each task. Accommodative and pupillary responses were measured with videoretinoscope Power Refractor 3 at 50 Hz.

RESULTS

Pupil size was largest in the Stroop task (M = 5.20 mm, SD = 0.75 mm), followed by the numerical tasks (M = 5.02 mm, SD = 0.72 mm) and textual tasks (M = 4.78 mm, SD = 0.71 mm). Accommodative fluctuations - measured as accommodation SD - were largest in the textual tasks (M = 0.67 D, SD = 0.34 D), followed by the numerical tasks (M = 0.61 D, SD = 0.40 D) and the Stroop task (M = 0.52 D, SD = 0.21 D).

CONCLUSIONS

In our experiment, short-term cognitive load was associated with altered pupillary and accommodative response to near tasks. In conflicting tasks (Stroop) or in performing continuing calculations, the pupils were larger; in tasks requiring logical reasoning, the accommodative fluctuations were greater. These effects can potentially be associated with current near-point stress and myopia growth models.

A Study to Analyze Refractive Errors in Relation to Age and Sex

Background and objective Refractive defects should be detected and treated early to avoid irreversible vision loss and other potential problems in the future. In this study, we aimed to analyze the refractive errors (REs) and their relationship with gender and age. Methods This study was conducted at the Northern Border University Health Center, Arar, Saudi Arabia. REs were analyzed using spherical equivalents (SEs), cylinders, and their orientations. SEs of REs were taken as half the cylinder plus the spherical component. Emmetropia was defined as SE between -0.50 and +0.50 diopter sphere (DS), myopia as SE ≤0.50 DS, and hyperopia as SE ≥0.50 DS for adults and SE ≥1.0 for children (up to 10 years). Statistical analysis was performed using the IBM SPSS Statistics software package (IBM, Armonk, NY). Qualitative data were presented as frequency and percentage while quantitative data were presented as mean and standard deviation (SD). Chi-square was used as a significant test and a p-value <0.05 was considered statistically significant. Results A total of 240 patients were included in the study. There were 138 men and 102 females aged 3-60 years (57.5 and 42.5%, respectively). The mean age of males was 24.4 years and that of females was 25.5 years. The p-value was statistically significant in terms of analysis with age. The study found an association between age and RE magnitude and variability. Conclusion Based on our findings, RE is a common problem that affects individuals of all ages. Regular screenings are advised for individuals in order to detect REs early.

Shedding light on myopia by studying complete congenital stationary night blindness

Myopia is the most common eye disorder, caused by heterogeneous genetic and environmental factors. Rare progressive and stationary inherited retinal disorders are often associated with high myopia. Genes implicated in myopia encode proteins involved in a variety of biological processes including eye morphogenesis, extracellular matrix organization, visual perception, circadian rhythms, and retinal signaling. Differentially expressed genes (DEGs) identified in animal models mimicking myopia are helpful in suggesting candidate genes implicated in human myopia. Complete congenital stationary night blindness (cCSNB) in humans and animal models represents an ON-bipolar cell signal transmission defect and is also associated with high myopia. Thus, it represents also an interesting model to identify myopia-related genes, as well as disease mechanisms. While the origin of night blindness is molecularly well established, further research is needed to elucidate the mechanisms of myopia development in subjects with cCSNB. Using whole transcriptome analysis on three different mouse models of cCSNB (in Gpr179^-/-, Lrit3^-/- and Grm6^-/-), we identified novel actors of the retinal signaling cascade, which are also novel candidate genes for myopia. Meta-analysis of our transcriptomic data with published transcriptomic databases and genome-wide association studies from myopia cases led us to propose new biological/cellular processes/mechanisms potentially at the origin of myopia in cCSNB subjects. The results provide a foundation to guide the development of pharmacological myopia therapies.

Spectacle lenses with slightly aspherical lenslets for myopia control: clinical trial design and baseline data

Objectives

Myopia is a major public health problem and it is essential to find safe and effective means to control its progression. The study design and baseline data are presented for a one-year prospective, double-masked, crossover, randomized clinical trial evaluating the efficacy of single vision spectacle lenses with concentric rings of slightly aspherical contiguous lenslets technology (SAL) on myopia control.

Methods

One hundred 8- to 13-year old Chinese children with a refractive error of -0.75 D to -4.75 D were assigned to two groups. In Group 1, SAL and single vision lenses were each worn for 6 months, and Group 2 wore the lenses in the reversed order. Primary outcomes are axial length and spherical equivalent of cycloplegic refractive error. Secondary outcomes included corneal thickness, anterior chamber depth, lens thickness, visual acuity, and lens adaptation.

Results

No significant differences in baseline parameters (cycloplegic spherical equivalent, axial length, age) were found between groups (0.49 < p < 0.94). All children adapted well to the test lenses and there was no significant difference in visual acuity between the SAL and single vision lenses (p = 0.27).

Conclusions

The children in the two well balanced groups had comparable visual acuity and adapted well to the test lenses. These results imply that visual acuity can be well improved by SAL lenses. Clear visual acuity provides the assurance for good compliance in this longitudinal study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02562-0.

Prevalence and Factors Associated with Myopia Among High School Students in Hawassa City, South Ethiopia, 2019

PURPOSE

Myopia is one of the avoidable causes of visual impairment. Twenty-seven percent of the world population were myopic in 2010 and after 30 years it is expected half of the peoples in the planet will become myopic. The aim of this study was to determine the prevalence and factors associated with myopia among high school students.

MATERIALS AND METHODS

A cross-sectional school-based study design using stratified simple random sampling technique was used to select 349 high school students from 21 high schools in Hawassa city. The study was conducted from April 24 to May 7, 2019. Structured questionnaire, six meter Snellen visual acuity chart, trial frame, trial set, retinoscope and cyclopentolate 1% eye drops were used to collect data. Data were analyzed using Statistical Package for Social Science (SPSS) version 20 computer software. Variables having p-value <0.05 in multivariate logistic regression were considered as statistically significant.

RESULTS

A total of 349 participants having a response rate of 97% were involved with the mean age of 16.90±1.32 years. Prevalence of myopia was 16.05% (95%CI: 12.6, 20.1). Early age of schooling (adjusted odds ratio, AOR=3.14; 95%CI: 1.16, 10.06), parents being myopic (AOR=8.46; 95%CI: 7.11, 12.08), prolonged near work (AOR=11.65; 95%CI: 2.11, 64.5), short working distance (AOR=10.90; 95%CI: 0.57, 20.55), lack of outdoor sport activities (AOR=7.37; 95%CI: 2.71, 20.03) and visual display unit (VDU) usage (AOR=8.36; 95%CI: 2.39, 29.33) were variables significantly associated with myopia.

CONCLUSION AND RECOMMENDATIONS

The prevalence of myopia was high in the study area. Early age of schooling, parents being myopic, prolonged near work, short working distance, lack of outdoor sport activities, and visual display unit usage were variables significantly associated with myopia. There should be strategies to prevent visual impairments secondary to myopia with affordable optical corrections and appropriate use of visual display units.

Risk Factors for Myopia in 2 Hong Kong School Systems: A Pilot Study

PURPOSE

Myopia has reached "epidemic" proportions, especially in several East Asian countries. Most myopia emerges during childhood, particularly during the school years. The aim of this study was to investigate myopia prevalence and compare risk factors of myopia among Hong Kong Chinese primary school children under 2 different educational systems.

DESIGN

Cross-sectional study.

METHODS

Visual assessments were conducted in 1 government-funded primary school (n = 159) and 1 international school (n = 223) in Hong Kong in September and October 2018, respectively. Measurements were performed on children aged 8 to 10 years old. Noncycloplegic refraction and axial length were measured, respectively. A validated questionnaire focusing on demographic information, nonscreen time (eg, reading and writing on paper materials), screen time (ie, smartphones and tablets usage), time spent on outdoor activities, and other myopia risk factors was completed by parents of participants.

RESULTS

The prevalence of myopia [37.5% vs 12.8%, P < 0.001; spherical equivalent refraction (SER) ≤ -1.00 diopter (D)] and refractive astigmatism [25.0% vs 7.2%, P < 0.001; cylinder (Cyl) ≥ 1.00 diopter cylinder (DC)] were significantly higher in the local school than in the international school. Students in the local school were slightly older than those attending the international school (9.17 ± 0.82 years vs 8.95 ± 0.85 years, P = 0.046), and there was no significant difference in gender distribution between the 2 schools (P = 0.51). There were significant differences in the demographic information including parental myopia (P < 0.001), family income (P < 0.001), and parents' educational level (P < 0.001) between the 2 schools. Multiple regression analysis showed that parental myopia history and continuous near work was associated with myopia in the local school, while the father's educational level was related to myopia in the international school.

CONCLUSIONS

In this pilot study, despite the much higher prevalence of parental myopia and high myopia in the international school, the myopia prevalence among the students is lower in this school than in the local school, suggesting that environmental factors other than genetics might have a stronger protective effect in this school population.

The effect of spatially-related environmental risk factors in visual scenes on myopia

Myopia, the most common refractive error, is estimated to affect over two billion people worldwide, especially children from East Asian regions. Children with early onset myopia have an increased risk of developing sight threatening complications in later life. In addition to the contribution of genetic factors, of which expression is controversially suggested to be subject to environmental regulation, various environmental factors, such as near-work, outdoor, and living environment, have also been determined to play significant roles in the development of refractive error, especially juvenile myopia. Cues from daily visual scenes, including lighting, spatial frequency, and optical defocus over the field of visual stimuli, are suggested to influence emmetropisation, thereby affecting myopia development and progression. These risk factors in visual scenes of the everyday life may explain the relationship between urbanicity and myopia prevalence. This review first summarises the previously reported associations between myopia development and everyday-life environments, including schooling, urban settings, and outdoors. Then, there is a discussion of the mechanisms hypothesised in the literature about the cues from different visual scenes of urbanicity in relation to myopia development.

Reduction in Accommodative Response of Schoolchildren by a Double-Mirror System

PURPOSE

This study first proposed the application of a double-mirror system (DMS) to extend viewing distance and investigate the accommodative response of schoolchildren under a DMS.

METHOD

Fifty-seven subjects aged between 7 and 12 years old were recruited in this study, and the experiment was divided into two stages. The first stage consisted of a case history inquiry, a refraction state, and a visual function examination. In the second stage, the subjects gazed at an object at distances of 0.4 m, 2.285 m, and through a DMS, respectively, and their accommodative responses were measured using an open-field autorefractor.

RESULTS

There was no significant difference in the schoolchildren's accommodative response between subjects gazing at an object at 2.285 m (0.14 ± 0.35 D, p > 0.05) and those gazing at it through a DMS (0.20 ± 0.35 D). However, their accommodative response showed a significant difference between subjects gazing at an object at 0.4 m and 2.285 m and those gazing at it at 0.4 m and through a DMS.

CONCLUSION

In this experiment, the results of the children's accommodative response measured at 2.285 m or through a DMS are very similar. The viewing distance can be extended by a DMS, resulting in accommodative relaxation. This result may have potential applications in myopia control.

Functional integration of eye tissues and refractive eye development: Mechanisms and pathways

Refractive eye development is a tightly coordinated developmental process. The general layout of the eye and its various components are established during embryonic development, which involves a complex cross-tissue signaling. The eye then undergoes a refinement process during the postnatal emmetropization process, which relies heavily on the integration of environmental and genetic factors and is controlled by an elaborate genetic network. This genetic network encodes a multilayered signaling cascade, which converts visual stimuli into molecular signals that guide the postnatal growth of the eye. The signaling cascade underlying refractive eye development spans across all ocular tissues and comprises multiple signaling pathways. Notably, tissue-tissue interaction plays a key role in both embryonic eye development and postnatal eye emmetropization. Recent advances in eye biometry, physiological optics and systems genetics of refractive error have significantly advanced our understanding of the biological processes involved in refractive eye development and provided a framework for the development of new treatment options for myopia. In this review, we summarize the recent data on the mechanisms and signaling pathways underlying refractive eye development and discuss new evidence suggesting a wide-spread signal integration across different tissues and ocular components involved in visually guided eye growth.

Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

Long-term progression of myopic maculopathy in degenerative myopia as imaged by SD-OCT and IR imaging

CLINICAL RELEVANCE

Clinicians can benefit from developing an understanding of the natural disease progression of myopic maculopathy in degenerative myopia using optical coherence tomography (OCT).

BACKGROUND

The prevalence of high myopia is constantly increasing. In this work, infrared imaging and OCT is used to study the natural course of the disease.

METHODS

This is a retrospective longitudinal study. Medical records of 72 patients with high myopia (< 6.00 D) and a minimum five-year follow-up period were analysed. Collected data on all enrolled patients included demographic characteristics and medical history, as well as recordings on best-corrected visual acuity, slitlamp examination, OCT, and fluorescein angiography in cases of suspected myopic choroidal neovascularisation. Images were independently marked by two graders.

RESULTS

The mean age of patients was 54.6 ± 14.4 years (59.72% female) with baseline logMAR best-corrected visual acuity of 0.22 ± 0.28. At baseline examination, 70.83% of the study group showed signs of maculopathy and 62.5% diffuse or patchy atrophy. During follow-up, 22.2% of patients with any type of atrophy showed enlarged affected areas. Two patients with baseline lacquer cracks developed new lesions. There was a weak correlation between patient age and maculopathy progression (r = 0.233; p = 0.03). While central retinal thickness was not associated with maculopathy progression (p = 0.203), a moderate correlation was found between choroidal thickness and maculopathy progression (r = -0.516; p < 0.001).

CONCLUSION

Lesion characteristics in myopic degeneration have been elucidated, taking advantage of the ongoing technological advances in retinal imaging. The understanding of disease patterns and progression is essential for appropriate management of patients, while discovering biomarkers which lead to choroidal neovascularisation development is of urgent importance to establish international diagnostic criteria and treatment protocols.

The association between nearwork-induced transient myopia and progression of refractive error: A 3-year cohort report from Beijing Myopia Progression Study

PURPOSE

To investigate the natural change of nearwork-induced transient myopia (NITM), and its association with the progression of refractive error.

METHODS

Students of the Beijing Myopia Progression Study were examined at baseline and follow-up examinations, which included cycloplegic autorefraction. Initial NITM and its decay were assessed objectively immediately after binocularly-viewing and performing a sustained 5-minute near task (20 cm).

RESULTS

There were 223 students with both NITM and cycloplegic refractive data enrolled. There were 142 myopic (63.7%), 32 emmetropic (14.4%), and 49 hyperopic (22.0%) students according to their baseline cycloplegic refraction. The annual refractive change was -0.45 (-0.73, -0.21) D. From the baseline to the one-year and two-year follow-up periods, the initial NITM (median) increased significantly in the myopic students (0.16, 0.21, and 0.20D, p = 0.01, respectively). The overall proportion of NITM decay types shifted significantly from none being induced at baseline (non-induced: 17.0%, complete decay 57.4%, incomplete decay 25.6%) to incomplete decay at the 2-year follow-up (non-induced: 6.7%, complete decay 65.0%, incomplete decay 28.3%, p = 0.01). For the hyperopic students, after adjusting for risk factors, for every 1 diopter increase in the initial NITM at baseline, there was approximately a -1.48 diopter more relative myopic refractive progression (p = 0.01). No significant association was found between refractive change and the NITM parameters for either the myopic or emmetropic students after adjusting for the same confounders. However, this relation was significant in the hyperopes (p = 0.01).

CONCLUSION

NITM was only found to be significantly associated with the progression of a myopic refractive shift among the hyperopes.

Predominance of hyperopia in autosomal dominant Best vitelliform macular dystrophy

Background/Aims

Patients with BEST1-associated autosomal dominant Best vitelliform macular dystrophy (AD-BVMD) have been reported to be hyperopic, but the prevalence of refractive error has not been described. This study aimed to characterise the type and degree of refractive error in a large cohort of patients with AD-BVMD compared with an age-similar group with ABCA4-associated Stargardt disease.

Methods

This was a retrospective chart review of consecutive patients with molecularly confirmed AD-BVMD and Stargardt macular dystrophy seen at a single academic centre. Demographic information, including age, gender and genotype were extracted from the chart. The best corrected visual acuity (BCVA), as well as type and degree of refractive error on manifest refraction for each eye on each visit, were recorded and compared.

Results

A total of 178 eyes from 89 patients with AD-BVMD (35 women, 54 men; mean age 36.6 years) and 306 eyes from 153 patients (94 women, 59 men, mean age 30.2 years) with Stargardt disease were included in the study. Mean BCVA was excellent for both AD-BVMD and Stargardt eyes (logMAR 0.23 vs logMAR 0.31, respectively; p=0.55). At initial refraction, 73.0% of AD-BVMD eyes (130/178) were hyperopic, with mean spherical equivalent (SE) +1.38 dioptres (median +0.88) whereas 80.7% of Stargardt eyes (247/306) were myopic, with mean SE of −1.76 dioptres (median −1.19) (p<0.001).

Conclusion

Patients with AD-BVMD are predominantly hyperopic, whereas those with Stargardt disease are predominantly myopic. The findings provide further evidence of a role for BEST1 in ocular growth and development.

PEDIATRIC RETINAL DETACHMENT IN AN ASIAN POPULATION WITH HIGH PREVALENCE OF MYOPIA: Clinical Characteristics, Surgical Outcomes, and Prognostic Factors

PURPOSE

To evaluate the clinical characteristics and surgical outcomes of pediatric retinal detachments (RDs) in an Asian population.

METHODS

Retrospective review of 171 eyes of 152 pediatric patients with rhegmatogenous RD over a 20-year period.

RESULTS

Myopia was the most common risk factor in our population. At 6 months, primary anatomical success was 60.7%, and overall anatomical success was 86.7%. A total of 46.8% had best-corrected visual acuity of 20/40 or better, and 81.6% had best-corrected visual acuity of 20/200 or better. In primary RDs, high myopia (≤-6D) patients had a lower primary anatomical success compared to patients with moderate myopia (≤-2D) (59.3 vs. 100% P = 0.03). Increasing age and absence of proliferative vitreoretinopathy were associated with anatomical and visual success. Pars plana vitrectomy as the primary procedure was associated with decreased odds of anatomical success. A longer duration of symptoms, cataract, and a larger RD extent were associated with poorer functional outcome.

CONCLUSION

Myopia was the commonest risk factor for pediatric RD in our population. Good anatomical and functional outcome can be achieved with surgery. Increasing age at presentation and absence of proliferative vitreoretinopathy was associated with anatomical and functional success. High myopia was associated with poorer anatomical and functional outcome.

Visual quality of juvenile myopes wearing multifocal soft contact lenses

Background

It is unclear whether multifocal soft contact lenses (MFSCLs) affect visual quality when they are used for myopia control in juvenile myopes. The aim of this study was, therefore, to investigate the effect of MFSCLs on visual quality among juvenile myopia subjects.

Methods

In a prospective, intervention study, thirty-three juvenile myopes were enrolled. Visual perception was assessed by a quality of vision (QoV) questionnaire with spectacles at baseline and after 1 month of MFSCL wear. At the one-month visit, the high (96%) contrast distance visual acuity (distance HCVA) and low (10%) contrast distance visual acuity (distance LCVA) were measured with single vision spectacle lenses, single vision soft contact lenses (SVSCLs) and MFSCLs in a random order. Wavefront aberrations were measured with SVSCLs, with MFSCLs, and without any correction.

Results

Neither distance HCVA (p > 0.05) nor distance LCVA (p > 0.05) revealed any significant difference between MFSCLs, SVSCLs and single vision spectacle lenses. The overall score (the sum of ten symptoms) of the QoV questionnaire did not show a statistically significant difference between spectacles at baseline and after 1 month of MFSCL wear (p = 0.357). The results showed that the frequency (p < 0.001), severity (p = 0.001) and bothersome degree (p = 0.016) of halos were significantly worse when wearing MFSCLs than when wearing single vision spectacle lenses. In contrast, the bothersome degree caused by focusing difficulty (p = 0.046) and the frequency of difficulty in judging distance or depth perception (p = 0.046) were better when wearing MFSCLs than when wearing single vision spectacle lenses. Compared with the naked eye, MFSCLs increased the total aberrations (p < 0.001), higher-order aberrations (p < 0.001), trefoil (p = 0.023), coma aberrations (p < 0.001) and spherical aberrations (SA) (p < 0.001). Compared with the SVSCLs, MFSCLs increased the total aberrations (p < 0.001), higher-order aberrations (p < 0.001), coma aberrations (p < 0.001) and SA (p < 0.001). The direction of SA was more positive (p < 0.001) with the MFSCLs and more negative (p = 0.001) with the SVSCLs compared with the naked eye.

Conclusions

Wearing MFSCLs can provide satisfactory corrected visual acuity (both distance HCVA and distance LCVA). Although the lenses increased the aberrations, such as total aberrations and higher-order aberrations, there were few adverse effects on the distance HCVA, distance LCVA and visual perception after 1 month of MFSCL use.

Trial registration

Chinese Clinical Trial Registry: ChiCTR-OOC-17012103. Registered 23 July 2017, http://www.chictr.org.cn/usercenter.aspx

Myopia progression over a 4-year period after laser-assisted refractive surgery in patients in their 20s and 30s

PURPOSE

To investigate the increase in refractive error (RE) and axial length (AL) in myopia patients in their 20s and 30s after laser-assisted in situ keratomileusis (LASIK) or epipolis-LASIK (epi-LASIK).

STUDY DESIGN

Retrospective cohort study.

METHODS

This retrospective study involved 280 eyes of 140 myopia patients who underwent LASIK or epi-LASIK at the Baptist Eye Institute, Kyoto, Japan and who were followed for more than 5 years postoperatively. The patients were divided into 2 groups according to age: group A (age range, 20-29 years) and group B (age range, 30-39 years). In all patients, the RE and AL were measured at 1, 2, 3, 4, and 5 years postoperatively, and the 2 groups were compared in terms of each surgical method.

RESULTS

The patients' mean age at surgery was 30.6 ± 4.9 years. No significant difference was found between the 2 groups in terms of the preoperative mean spherical equivalent (SE) or AL. In the LASIK group, the mean changes in SE during the 4 years of study in groups A and B were + 0.054 ± 0.256 D and + 0.052 ± 0.327 D, respectively (P = .93, NS), and the postoperative increases in AL were 0.059 ± 0.134 mm and 0.027 ± 0.133 mm, respectively (P = .08, NS). In the epi-LASIK group, the mean change in SE during the 4 years of study in groups A and B were  -0.438 ± 0.207 D and -0.259 ± 0.454 D, respectively (P = .41, NS), and the postoperative increases in AL were 0.124 ± 0.141 mm and 0.094 ± 0.166 mm, respectively (P = .46, NS).

CONCLUSION

Our findings showed no significant difference in myopia progression in patients in their 20s and 30s during a 4-year period after either LASIK or epi-LASIK.

Prevalence and risk factors of myopia in Han and Yugur older adults in Gansu, China: a cross-sectional study

Few studies have investigated the prevalence of myopia in Northwest China. This cross-sectional study aimed to investigate the prevalence and associated factors of myopia and high myopia in adults aged 40–80 years in the Han and Yugur populations living in Gansu Province, Northwest China. A total of 3,845 participants were included. The overall age- and sex-adjusted prevalence of myopia (spherical equivalent (SE) < −0.5 D), high myopia (SE < −6.0 D) and hyperopia (SE > + 0.5 D) were 16.4%, 0.7% and 26.2% in Yugur participants, respectively, and 34.3%, 5.0% and 19.2% in Han participants, respectively. The prevalence of myopia and high myopia in Han participants was significantly higher than that in Yugur participants (both P < 0.001). Yugur population, birth in rural areas, smoking history and outdoor work were found to be negatively associated with myopia. Higher education level and a family history of myopia were found to be positively associated with myopia in the study population. High myopia was negatively associated with Yugur population, aging, birth in rural areas and was positively associated with a family history of myopia. This study provided valuable information regarding the environmental risk factors of myopia and revealed an ethnic disparity in the prevalence of myopia in Gansu Province, Northwest China.

A Serial Cross-Sectional Analysis of the Prevalence, Risk Factors and Geographic Variations of Reduced Visual Acuity in Primary and Secondary Students from 2000 to 2017 in Hong Kong

Background: We would like to investigate the prevalence trend, potential risk factors and geographic features of reduced visual acuity (VA) in primary and secondary schoolchildren of Hong Kong. Methods: This was a serial cross-sectional study using historical data of schoolchildren aged 6 to 15 years from the annual health checks conducted at Student Health Service Centers across Hong Kong, for the school years of 2000/2001 to 2016/2017. Results: The prevalence of reduced VA increased from 49.23% (95% CI, 48.99-49.47) in 2000/2001 to 54.34% (95% CI, 54.10-54.58) in 2011/2012 but decreased to 51.42% (95% CI, 51.17-51.66) in 2016/2017. Girls were less susceptible than boys at age 6-7 (and in grade primary 1-2), but more susceptible at older ages. The prevalence in junior grades increased while the risk effect of grade reduced over the past 17 years. Geographic variation on the risk for reduced VA existed and spatial autocorrelation was positive. The difference in prevalence of reduced VA between Hong Kong and mainland China has decreased in recent years. Cross-border students living in mainland China were associated with a lower risk for reduced VA. Conclusions: Further study was proposed to investigate the environmental association between students living in and outside Hong Kong with the prevalence of reduced VA. Multi-level research should also be conducted to investigate the influence of compositional and contextual factors on the prevalence of reduced VA.

Inverting peripheral hyperopic defocus into myopic defocus among myopic schoolchildren using addition power of multifocal contact lens

PURPOSE:

The purpose was to determine the minimum near-addition power needed using Proclear^® multifocal D-Design contact lens (adds: +1.50 D, +2.50 D, +3.00 D, and +3.50 D) to invert the pattern of relative hyperopic defocus in the peripheral retina into relative myopic defocus among the eyes of myopic schoolchildren.

METHODS:

Twenty-seven right eyes (24 females and 3 males) of 27 myopic schoolchildren aged between 13 and 15 years were included in this study. The measurements of central refraction, peripheral refraction (between 35° temporal and 35° nasal visual field in 5° steps), and lag of accommodation were conducted using the Grand-Seiko WR-5100K open-field autorefractometer initially without correction (WC), followed by with correction using four different addition powers of Proclear^® multifocal D-Design contact lens in random sequence. Axial length was measured using a handheld probe ultrasound A-scan (Tomey AL-2000).

RESULTS:

The relative peripheral refractive error showed high hyperopic defocus of +1.08 ± 1.24 D at 35° nasal and +1.06 ± 1.06 D at 35° temporal visual field WC. All Proclear multifocal contact lenses (MFCLs) decreased the peripheral hyperopic defocus with increasing addition powers (F [2.938, 47.001] = 13.317, P < 0.001). However, only +3.00 D addition and +3.50 D addition (P = 0.001) could invert the peripheral hyperopic defocus into peripheral myopic defocus. Apart from that, the +3.00 D addition lens showed the lowest lag of accommodation (+1.10 ± 0.83 D) among the other MFCL adds (P = 0.002).

CONCLUSION:

A +3.00 D addition Proclear MFCL is the optimal addition power that can invert the pattern of peripheral hyperopic defocus into myopic defocus.

Tears and Eyewear in Forensic Investigation-A Review

Body fluid analysis has played a crucial role in ascertaining various characteristics and has greatly aided in reconstructing events during crime scene investigation. It is often presumed that crimes that involve violence and mental disturbances such as murder or sexual assault provide good sources of body fluids such as blood, saliva, semen, vaginal secretions, urine and tears. Tears are secreted in response to any emotional or stressful situations and may be found deposited on surfaces such as bedding, tissue paper or cloth. In the absence of the commonly noted body fluids such as blood or saliva, tears can play an important role that can lead to personal identification by examining the biochemistry and molecular aspects to obtain a full DNA profile. Additionally, identification of an individual may be done by carefully observing certain unique eye characteristics such as heterochromia which is highly individualistic. Characteristics of eyewear such as spectacles and contact lenses have unique properties and prescription criteria for correcting an individual's eyesight that can provide vital clues in understanding the visual ability of an individual. In crime scene investigation, the presence or absence of eyewear provides immense evidentiary value that has greatly aided in solving cases such as Janet Abaroa's Murder. This paper provides a systematic review of the possibility of using tears and eyewear for the purpose of forensic investigation and to statistically support the inferences with prescription databases which may be initiated across different populations. Forensic Optometry is yet to get streamlined along with the routinely followed investigative techniques and scientifically explored although no standard protocols exist to analyse eyewear. The use of behavioural optometry is gaining attention in the context of driving laws of different countries and is a simple but powerful indicator of abnormal behaviour. It is speculated that the last seen image referred to as an 'Optogram' of an individual may be captured in the retina since our eyes functions like a camera. Although this claim is considerably unexplored, it is quite possible that the last seen image of a criminal, objects or a place may be noted that can positively help in linking individuals at the scene of crime or identify the primary crime location. In this review, the potential for new insights into the analysis of tears, eye and eyewear characteristics have been explored.

Refractive status and prevalence of myopia among Chinese primary school students

BACKGROUND

The aim of this study was to investigate the prevalence of myopia in key (university-oriented) and non-key elementary schools in China using a traditional and a new criterion for myopia diagnosis in an epidemiological study.

METHODS

This school-based, cross-sectional study examined students from four key schools and seven non-key schools. Non-cycloplegic autorefraction and visual acuity (VA) were performed on each student. Myopia was defined as a spherical equivalent (SE) refractive error not better than -1.00 D. A questionnaire was also administered.

RESULTS

Of the 13,220 students examined, 6,546 (49.5 per cent) had myopia using the criterion of SE not better than -1.00 D. However, 2,246 (34.3 per cent) of these myopes had VA ≥ 0 logMAR in both eyes, indicating they were not functioning as myopes. Thus, a second myopia criterion was adopted: SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye. By this definition, only 32.5 per cent of the overall sample had myopia. Students in key schools had a higher prevalence of myopia than those in non-key schools (53.8 per cent versus 44.7 per cent) by the initial criterion. By the new criterion, the prevalence of myopia was 41.2 per cent versus 22.7 per cent. Myopia was equal in grade 1 of both school types, but accelerated faster in key schools, where there was a much higher prevalence of myopia by fourth grade, and continued up to 79.2 per cent prevalence by sixth grade based on SE refractive error not better than -1.00 D.

CONCLUSION

Students in more competitive university-oriented elementary schools developed myopia much faster than those in regular schools, although they started with the same level of myopia. Since one-third of the 'myopes' had VA ≥ 0 logMAR in both eyes, they would not be prescribed a correction, or be clinically treated as myopes. A new criterion of SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye was tested. This criterion is more clinically appropriate and could be used in future epidemiological studies.

Comparison of Individual Retinal Layer Thicknesses between Highly Myopic Eyes and Normal Control Eyes Using Retinal Layer Segmentation Analysis

The incidence of myopia is increasing worldwide, and the investigation on pathophysiology of myopia is becoming more important. This retrospective study aimed to compare the thicknesses of individual retinal layers between high-myopic and control eyes, and to evaluate the effects of age and sex on each retinal layer thickness. We assessed 164 subjects and divided them into two groups based on axial length (AL) (i.e., high-myopic group (AL ≥ 26 mm) and control group (AL < 26 mm)). Individual retinal layer thicknesses of five subfields in the macula were measured using automated retinal segmentation software packaged with the spectral-domain optical coherence tomography and were compared. In high-myopia group, the thicknesses of total retina and all individual retinal layers in central and entire perifoveal subfields were significantly thicker than the corresponding layers in control group after adjustment for ocular magnification (all P < 0.05). There were no significant effects of sex on individual retinal thicknesses, and age had less negative effects on the thicknesses of retina layers in high-myopic eyes than normal eyes. Axially elongated, non-pathologic highly myopic eyes had different structural features than control eyes, with significantly greater individual macular layer thicknesses independent of sex or age.

IMI - Myopia Control Reports Overview and Introduction

With the growing prevalence of myopia, already at epidemic levels in some countries, there is an urgent need for new management approaches. However, with the increasing number of research publications on the topic of myopia control, there is also a clear necessity for agreement and guidance on key issues, including on how myopia should be defined and how interventions, validated by well-conducted clinical trials, should be appropriately and ethically applied. The International Myopia Institute (IMI) reports the critical review and synthesis of the research evidence to date, from animal models, genetics, clinical studies, and randomized controlled trials, by more than 85 multidisciplinary experts in the field, as the basis for the recommendations contained therein. As background to the need for myopia control, the risk factors for myopia onset and progression are reviewed. The seven generated reports are summarized: (1) Defining and Classifying Myopia, (2) Experimental Models of Emmetropization and Myopia, (3) Myopia Genetics, (4) Interventions for Myopia Onset and Progression, (5) Clinical Myopia Control Trials and Instrumentation, (6) Industry Guidelines and Ethical Considerations for Myopia Control, and (7) Clinical Myopia Management Guidelines.

Analysis of genetic networks regulating refractive eye development in collaborative cross progenitor strain mice reveals new genes and pathways underlying human myopia

BACKGROUND

Population studies suggest that genetic factors play an important role in refractive error development; however, the precise role of genetic background and the composition of the signaling pathways underlying refractive eye development remain poorly understood.

METHODS

Here, we analyzed normal refractive development and susceptibility to form-deprivation myopia in the eight progenitor mouse strains of the Collaborative Cross (CC). We used RNA-seq to analyze gene expression in the retinae of these mice and reconstruct genetic networks and signaling pathways underlying refractive eye development. We also utilized genome-wide gene-based association analysis to identify mouse genes and pathways associated with myopia in humans.

RESULTS

Genetic background strongly influenced both baseline refractive development and susceptibility to environmentally-induced myopia. Baseline refractive errors ranged from - 21.2 diopters (D) in 129S1/svlmj mice to + 22.0 D in CAST/EiJ mice and represented a continuous distribution typical of a quantitative genetic trait. The extent of induced form-deprivation myopia ranged from - 5.6 D in NZO/HILtJ mice to - 20.0 D in CAST/EiJ mice and also followed a continuous distribution. Whole-genome (RNA-seq) gene expression profiling in retinae from CC progenitor strains identified genes whose expression level correlated with either baseline refractive error or susceptibility to myopia. Expression levels of 2,302 genes correlated with the baseline refractive state of the eye, whereas 1,917 genes correlated with susceptibility to induced myopia. Genome-wide gene-based association analysis in the CREAM and UK Biobank human cohorts revealed that 985 of the above genes were associated with myopia in humans, including 847 genes which were implicated in the development of human myopia for the first time. Although the gene sets controlling baseline refractive development and those regulating susceptibility to myopia overlapped, these two processes appeared to be controlled by largely distinct sets of genes.

CONCLUSIONS

Comparison with data for other animal models of myopia revealed that the genes identified in this study comprise a well-defined set of retinal signaling pathways, which are highly conserved across different vertebrate species. These results identify major signaling pathways involved in refractive eye development and provide attractive targets for the development of anti-myopia drugs.

The influence of age, refractive error, visual demand and lighting conditions on accommodative ability in Malay children and adults

PURPOSE

Near work, accommodative inaccuracy and ambient lighting conditions have all been implicated in the development of myopia. However, differences in accommodative responses with age and refractive error under different visual conditions remain unclear. This study explores differences in accommodative ability and refractive error with exposure to differing ambient illumination and visual demands in Malay schoolchildren and adults.

METHODS

Sixty young adults (21-25 years) and 60 schoolchildren (8-12 years) were recruited. Accommodative lag and accommodative fluctuations at far (6 m) and near (25 cm) were measured using the Grand Seiko WAM-5500 open-field autorefractor. The effects of mesopic room illumination on accommodation were also investigated.

RESULTS

Repeated-measures ANOVA indicated that accommodative lag at far and near differed significantly between schoolchildren and young adults [F(1.219, 35.354) = 11.857, p < 0.05]. Post hoc tests using the Bonferroni correction showed that at near, there was a greater lag in schoolchildren (0.486 ± 0.181 D) than young adults (0.259 ± 0.209 D, p < 0.05). Repeated-measures ANOVA also revealed that accommodative lag at near demands differed statistically between the non-myopic and myopic groups in young adults and schoolchildren [F(3.107, 31.431) = 12.187, p < 0.05]. Post hoc tests with Bonferroni correction showed that accommodative lag at near was significantly greater in myopic schoolchildren (0.655 ± 0.198 D) than in non-myopic schoolchildren (0.202 ± 0.141 D, p < 0.05) and myopic young adults (0.316 ± 0.172 D, p < 0.05), but no significant difference was found between myopic young adults (0.316 ± 0.172 D) and non-myopic young adults (0.242 ± 0.126 D, p > 0.05). Accommodative lag and fluctuations were greater under mesopic room conditions for all ages [all p < 0.05].

CONCLUSION

Greater accommodative lag was found in myopes than in emmetropes, in schoolchildren than in adults, and under mesopic conditions than under photopic conditions. Accommodative fluctuations were greatest in myopes and in mesopic conditions. These results suggest that differences exist in the amount of blur experienced by myopes and non-myopes at different ages and under different lighting conditions.

Electronic devices and myopic refraction among children aged 6-14 years in urban areas of Tianjin, China

PURPOSE

To assess associations between different types of electronic devices, myopic refraction and ocular biometric parameters in children aged 6-14 years in urban areas of Tianjin, China.

METHODS

A school-based, cross-sectional study was performed on 566 children (302 boys and 264 girls). The children underwent a comprehensive eye examination, including cycloplegic autorefraction and ocular biometry. The children's parents completed a detailed questionnaire that included each child's demographics, the use of electronic devices and other related risk factors.

RESULTS

Myopia was not associated with time spent using various electronic devices. However, the mean spherical equivalent refraction (SER) decreased by 0.28 D (p = 0.042) and 0.33 D (p = 0.018) for each 1-h increase in the time spent using smart phones and computers, respectively. In the multiple linear regression analyses of factors associated with the SER, the standardised coefficient B for time spent reading and writing was approximately four to five times larger than the standardised coefficient for time spent using smart phones or computers. Time spent using tablets and watching television was not significantly associated with the SER. A longer axial length (AL) was associated with more time spent using smart phones (B = 0.23, p = 0.006) and computers (B = 0.26, p = 0.002) but not using tablets (p = 0.45) and watching television (p = 0.45). No significant association was found between other ocular biometric parameters and time spent using various electronic devices.

CONCLUSIONS

On average, a more myopic SER and longer AL were both associated with more time spent using smart phones and computers, but not with time spent using tablets and watching television. The magnitude of the association between SER and time spent reading and writing was a substantially larger than that for smart phone or computer use. Different types of electronic devices had differing levels of association with myopic refraction.

Retardation of Myopia Progression by Multifocal Soft Contact Lenses

Myopia is an important public health problem due to its prevalence and significant public health cost. Elevating levels of myopia increase the risk of vision impairment, and therefore, high myopia has become one of the main causes of untreatable vision loss throughout the world due to its irreversible complications. At present, many options for slowing progression of myopia have already been proposed and evaluated such as progressive addition of executive bifocal spectacle lenses, peripheral defocusing lenses, overnight orthokeratology, pharmacological agents such as atropine eye drops, and multifocal soft contact lenses (MFSCLs). Use of MFSCLs has especially increased in recent years due to the growing demand to slow myopia progression during patient's adolescent growth period to avoid pathological myopia in adulthood. Compared with the other traditional methods of controlling myopia, MFSCLs allow myopic patients to better maintain their clear visual quality and slow myopia progression. In this manuscript, we aim to review the basics of myopia, recent advances in contact lenses to control myopia with emphasis on MFSCLs, define the elements for proper MFSCL fittings (such as pupil size, aberrations, accommodation and centering), discuss the potential rebound effect after discontinuation of contact lenses, and future directions for improvements of contact lenses for the control of myopia.

A Review of Current Concepts of the Etiology and Treatment of Myopia

Myopia occurs in more than 50% of the population in many industrialized countries and is expected to increase; complications associated with axial elongation from myopia are the sixth leading cause of blindness. Thus, understanding its etiology, epidemiology, and the results of various treatment regiments may modify current care and result in a reduction in morbidity from progressive myopia. This rapid increase cannot be explained by genetics alone. Current animal and human research demonstrates that myopia development is a result of the interplay between genetic and the environmental factors. The prevalence of myopia is higher in individuals whose both parents are myopic, suggesting that genetic factors are clearly involved in myopia development. At the same time, population studies suggest that development of myopia is associated with education and the amount time spent doing near work; hence, activities increase the exposure to optical blur. Recently, there has been an increase in efforts to slow the progression of myopia because of its relationship to the development of serious pathological conditions such as macular degeneration, retinal detachments, glaucoma, and cataracts. We reviewed meta-analysis and other of current treatments that include: atropine, progressive addition spectacle lenses, orthokeratology, and multifocal contact lenses.

The Effect of Longer-Term and Exclusive Breastfeeding Promotion on Visual Outcome in Adolescence

Purpose

Breastfeeding may influence early visual development. We examined whether an intervention to promote increased duration and exclusivity of breastfeeding improves visual outcomes at 16 years of age.

Methods

Follow-up of a cluster-randomized trial in 31 Belarusian maternity hospitals/polyclinics randomized to receive a breastfeeding promotion intervention, or usual care, where 46% vs. 3% were exclusively breastfed at 3 months respectively. Low vision in either eye was defined as unaided logMAR vision of ≥0.3 or worse (equivalent to Snellen 20/40) and was used as the primary outcome. Open-field autorefraction in a subset (n = 963) suggested that 84% of those with low vision were myopic. Primary analysis was based on modified intention-to-treat, accounting for clustering within hospitals/clinics. Observational analyses also examined the effect of breastfeeding duration and exclusivity, as well as other sociodemographic and environmental determinants of low vision.

Results

A total of 13,392 of 17,046 (79%) participants were followed up at 16 years. Low vision prevalence was 19.6% (95% confidence interval [CI]: 17.5, 22.0%) in the experimental group versus 21.6% (19.5, 23.8%) in the control group. Cluster-adjusted odds ratio (OR) of low vision associated with the intervention was 0.92 (95% CI: 0.73, 1.16); 0.88 (95% CI: 0.74, 1.05) after adjustment for parental and early life factors. In observational analyses, breastfeeding duration and exclusivity had no significant effect on low vision. However, maternal age at birth (OR: 1.13, 95% CI: 1.07, 1.14/5-year increase) and urban versus rural residence were associated with increased risk of low vision. Lower parental education, number of older siblings was associated with a lower risk of low vision; boys had lower risk compared with girls (0.64, 95% CI: 0.59,0.70).

Conclusions

Exclusive breastfeeding promotion had no significant effect on visual outcomes in this study, but other environmental factors showed strong associations. (ClinicalTrials.gov number, NCT01561612.)

Negative effects of transthyretin in high myopic vitreous on diabetic retinopathy

AIM

To analyze the relationship between vitreous transthyretin (TTR) levels, high myopia and diabetic retinopathy (DR).

METHODS

We selected 6722 individuals from the southern Jiangsu Province for diabetes and ophthalmic examinations. The TTR concentration in the vitreous of 50 patients with high myopia and diabetes, 50 patients with only DR, and 20 healthy controls were determined by ELISA. Key factors in Tie2 pathway in DR development including vascular endothecial growth factor (VEGF), Tie2, Angpt1, Angpt2, vascular endothelial growth factor receptor (VEGFR) 1 and VEGFR2 were also detected by ELISA.

RESULTS

The prevalence of DR in patients with diabetes and myopia [<6.00 diopter (D)], diabetes and high myopia (>6.00 D), and diabetes without myopia were 11.1%, 2.5%, and 60.0%, respectively. The vitreous TTR concentration of patients with diabetes and high myopia was approximately 6.5- and 4.2-times higher than those of patients with DR and healthy controls, respectively (P<0.05). Following the vitreous TTR concentration, the levels of VEGF, Tie2, Angpt1, Angpt2, VEGFR1 and VEGFR2 in vitreous of diabetes and high myopia patients, DR patients and healthy controls were detected as dramatically fluctuated.

CONCLUSION

The results suggest that TTR can affect the vitreous contents of key factors in Tie2 pathway for neovascularization, and there should be a protective association between abundant TTR levels in the vitreous of highly myopic patients and a decreased risk of DR.

Paediatric retinal detachment: a review

Paediatric retinal detachment (PRD) is an uncommon and challenging disease; it differs from adult detachments in etiology, anatomical characteristics, management and prognosis. PRDs can be particularly challenging, even for the most expert paediatric surgeons due to the higher prevalence of total retinal detachments, late diagnosis and bilateral involvement with respect to those which occur in adulthood. Moreover, the anatomical success, when achieved, is frequently not related to a functional recover. Postsurgical adverse events, refractive errors and amblyopia may additionally undermine the final outcome. Up to date there are few reviews regarding the approach of retinal detachment in children, mainly dealing with rhegmatogenous retinal detachment. In this review, rhegmatogenous, retinopathy of prematurity-related and Coats'-related PRDs were considered. The available literature from the last decades were reviewed and summarized. Epidemiology, etiology and clinical presentation, together with therapeutic approaches and outcomes have been reviewed and discussed.

CHOROIDAL THICKNESS IN HEALTHY CHINESE CHILDREN AGED 6 to 12: The Shanghai Children Eye Study

PURPOSE

To explore the characteristics of choroidal thickness (ChT) in Chinese children.

METHODS

A total of 144 healthy children, aged 6 years to 12 years old, were enrolled in the study. The ChT of subfovea and peripheral locations 0.5, 1.5, and 2.5 mm away from the fovea were evaluated by enhanced depth imaging optical coherence tomography. The association between subfoveal ChT and systemic, as well as ocular factors, including age, sex, height, weight, body mass index, axial length, refractive error, intraocular pressure, preterm history, and the refractive status of parents were studied.

RESULTS

The mean subfoveal ChT was 302 ± 63 μm. In the nasal, superior, and inferior areas, the ChT of locations closer to the fovea was thicker than those farther away from the fovea (all P < 0.05); however, ChT was not significantly different among different locations in the temporal area (P = 0.16). The ChT of the nasal quadrant was significantly thinner than that of other areas (P < 0.01). Subfoveal ChT decreased with age, axial length, preterm history, and increased with height. Sex was not statistically associated with subfoveal ChT.

CONCLUSION

In Chinese children, the ChT is thinnest in the nasal quadrant and thicker in central regions than in peripheral areas. The subfoveal ChT independently decreases with age, axial length, preterm history, and increases with height.

Myopigenic Activity Change and Its Risk Factors in Urban Students in Beijing: Three-Year Report of Beijing Myopia Progression Study

PURPOSE

To investigate the myopigenic activity change and its risk factors in urban students in Beijing.

METHODS

A total of 241 primary or secondary students aged 6-17 years from the Beijing Myopia Progression Study (BMPS) were re-examined 3 years after their baseline enrollment. A detailed questionnaire was administered to assess myopigenic activities at both baseline and at the 3-year follow-up. Altogether, 217 students (90.0%) with completed data were included in the analysis.

RESULTS

Compared to baseline, primary students (n = 123) had significant increases in outdoor sports time (mean ± standard deviation: 3.5 ± 4.3 vs. 2.4 ± 3.0 hours/week, p = 0.02), near work time (32.1 ± 13.4 vs. 24.8 ± 9.2 hours/week, p < 0.001), diopter hours (128.8 ± 53.3 vs. 97.5 ± 35.9 diopter hours/week, p < 0.001), and indoor time (53.8 ± 22.8 vs. 41.4 ± 16.9 hours/week, p < 0.001) at the 3-year follow-up. At both baseline and follow-up, females spent less time than males on outdoor sports (baseline: 2.4 ± 2.8 vs. 4.0 ± 5.2 hours/week, p = 0.006; follow-up: 2.3 ± 3.1 vs. 5.1 ± 5.0 hours/week, p < 0.001), and total outdoors (baseline: 11.9 ± 7.9 vs. 14.4 ± 9.5 hours/week, p = 0.03; follow-up: 10.5 ± 8.2 vs. 13.9 ± 9.6 hours/week, p = 0.005). In the multivariate regression analysis after adjustment by student's gender, younger students had more increase in both near work time (slope = -0.99 hours/week for age, p = 0.009) and indoor time (slope = -2.04 hours/week for age, p = 0.001).

CONCLUSIONS

During the 3-year follow-up, primary students had more myopigenic activities. Female students had more myopigenic activities than males at both baseline and follow-up. Children's age was a significant risk factor for this myopigenic activity change.

Association of Body Length with Ocular Parameters in Mice

PURPOSE

To determine the association between changes in body length with ocular refraction, corneal radii, axial length, and lens thickness in two different mouse strains.

METHODS

Body length, ocular refraction, corneal radii, axial length, and lens thickness were measured for two inbred mouse strains: 129S1/SvJ (n = 7) and C57BL/6 J (n = 10) from 4 to 12 weeks of age. Body length, from tip of nose to base of tail, was obtained using a digital camera. Biometric parameters, corneal radii, and refractions were measured using spectral-domain optical coherence tomography, automated keratometry, and infrared photorefraction, respectively. A mixed-model ANOVA was performed to examine the changes in ocular parameters as a function of body length and strain in mice controlling for age, gender, and weight over time.

RESULTS

C57BL/6J mice had significantly longer body length (average body length at 10 weeks, 8.60 ± 0.06 cm) compared to 129S1/SvJ mice (8.31 ± 0.05 cm) during development (P < .001). C57BL/6J mice had significantly hyperopic refractions compared to 129S1/SvJ mice across age (mean refraction at 10 weeks, 129S1/SvJ: +0.99 ± 0.44D vs. C57BL/6J: +6.24 ± 0.38D, P < .001). Corneal radius of curvature, axial length, and lens thickness (except 10 weeks lens thickness) were similar between the two strains throughout the measurement. In the mixed-model ANOVA, changes in body length showed an independent and significant association with the changes in refraction (P = .002) and corneal radii (P = .016) for each mouse strain. No significant association was found between the changes in axial length (P = .925) or lens thickness (P = .973) as a function of body length and strain.

CONCLUSIONS

Changes in body length are significantly associated with the changes in ocular refraction and corneal radii in different mouse strains. Future studies are needed to determine if the association between body length and ocular refraction are related to changes in corneal curvature in mice.

Circadian Patterns of Intraocular Pressure Fluctuation among Normal-Tension Glaucoma Optic Disc Phenotypes

OBJECTIVE

To characterize the 24-h habitual-position intraocular pressure (IOP) patterns of optic disc phenotypes (ODPs) in untreated normal-tension glaucoma (NTG) and the relationships between nocturnal IOP elevation and various clinical factors.

DESIGN

Prospective, cross-sectional, observational study.

METHODS

Eighty-two NTG patients with focal ischemic (FI) ODP and 82 age- and disease severity-matched NTG patients with myopic glaucomatous (MG) ODP were recruited prospectively over 3 years. The IOP was recorded 11 times over a 24-hour (h) period by a single ophthalmologist using a hand-held tonometer (TonoPen®XL). A cosinor model was used to describe the 24-h IOP rhythm. Associations between nocturnal IOP elevation and both ocular and demographic variables were evaluated using the generalized estimating equation (GEE).

RESULTS

Mean habitual-position IOP was significantly higher during nighttime than daytime in the FI group (16.44 vs. 14.23 mmHg, P < 0.001), but not in the MG group (15.91 vs. 15.70 mmHg, P = 0.82). The FI group also exhibited a significantly higher peak IOP during sleeping hours (P = 0.01) and lower trough IOP during the 24-h period than the MG group (P < 0.01). The MG group showed a significantly higher peak IOP during waking hours than the FI group (P < 0.01). Therefore, 24-h IOP fluctuation range was significantly higher in the FI group than the MG group (P = 0.013). In the FI group, peak habitual-position IOP and the highest frequency of IOP peaks occurred during sleeping hours (12 AM-6 AM). By contrast, IOP peaks in the MG group occurred during morning hours (8 AM-12 PM). The FI group showed an overall nocturnal acrophase in habitual-position IOP, with 45 patients (54.9%) having a nocturnal acrophase; 10 (12.2%), a diurnal acrophase; and 27 (32.9%), no evident acrophase. By contrast, the MG group showed no evident peak in habitual-position IOP, with 9 patients (10.9%) having a nocturnal acrophase; 43 (52.4%), a diurnal acrophase; and 30 (36.6%), no evident acrophase. In multivariate modeling using the GEE, ODP (P < 0.001) and spherical equivalent (SE, P = 0.001) were independently associated with nocturnal IOP elevation.

CONCLUSIONS

Based on 24-h habitual-position IOP data, FI is associated with significant nocturnal IOP elevation, while no such nocturnal IOP elevation is observed in MG ODP. In untreated NTG, there are also significant differences in the 24-h IOP pattern between FI and MG ODPs.

Large-Scale microRNA Expression Profiling Identifies Putative Retinal miRNA-mRNA Signaling Pathways Underlying Form-Deprivation Myopia in Mice

Development of myopia is associated with large-scale changes in ocular tissue gene expression. Although differential expression of coding genes underlying development of myopia has been a subject of intense investigation, the role of non-coding genes such as microRNAs in the development of myopia is largely unknown. In this study, we explored myopia-associated miRNA expression profiles in the retina and sclera of C57Bl/6J mice with experimentally induced myopia using microarray technology. We found a total of 53 differentially expressed miRNAs in the retina and no differences in miRNA expression in the sclera of C57BL/6J mice after 10 days of visual form deprivation, which induced -6.93 ± 2.44 D (p < 0.000001, n = 12) of myopia. We also identified their putative mRNA targets among mRNAs found to be differentially expressed in myopic retina and potential signaling pathways involved in the development of form-deprivation myopia using miRNA-mRNA interaction network analysis. Analysis of myopia-associated signaling pathways revealed that myopic response to visual form deprivation in the retina is regulated by a small number of highly integrated signaling pathways. Our findings highlighted that changes in microRNA expression are involved in the regulation of refractive eye development and predicted how they may be involved in the development of myopia by regulating retinal gene expression.

The influence of near work on myopic refractive change in urban students in Beijing: a three-year follow-up report

PURPOSE

To investigate the influence of daily activities on myopic refractive change and myopic onset in Chinese urban students.

METHODS

The Beijing Myopia Progression Study was a 3-year cohort study. Cycloplegic refraction and a daily activity questionnaire were assessed at baseline and at follow-up examinations. Refractive change was defined as the difference in cycloplegic spherical equivalent (SE) between the final follow-up and baseline. 386 students were initially enrolled in the baseline study.

RESULTS

At the final follow-up, 222 students (57.5 %) with completed refractive error and daily activity data were analyzed. These students spent 0.32 ± 2.33 h/day more on near work (p = 0.04), and 0.21 ± 1.31 h/day less on outdoor leisure (p = 0.02), than they did at baseline. In the multivariate analysis, the younger among the secondary students (β = 0.06, p < 0.001), and those with more near work hours at baseline (β = -0.028, p = 0.033), exhibited more myopic refractive change. However, myopic refractive change was not found to be significantly associated with near work hours in the primary students, or with time spent outdoors, in either school level. After stratifying the activity hours into quartile groups, students with a greater near work load at baseline (trend P = 0.03) exhibited a greater myopic refractive change and had a higher risk to develop myopia (hazard ratio, 95 % confidence interval: 5.19, 1.49-18.13), after adjusting for the confounders. However, no significant association was found related to outdoor activity.

CONCLUSIONS

In this cohort, children with a greater near work load at baseline exhibited more myopic refractive change and were also more likely to develop myopia. The protective effect of outdoor activity on myopic refractive change was not observed.

Changes in Myopia Prevalence among First-Year University Students in 12 Years

PURPOSE

The aim of this study is to compare the changes in myopia prevalence among Portuguese first-year university students in 2002 and 2014 at the University of Minho.

METHODS

The refractive status and axial length of first-year students at the School of Sciences, University of Minho, were measured in 2014. Refractive error was measured with subjective refraction under cycloplegia and axial length was measured by optical biometry. The data were compared with those obtained from a similar cohort of 111 students in 2002. Myopia was defined as a mean spherical equivalent of ≤-0.50D. A survey was conducted to know the routine of the participants. They were asked how many hours per week (hrs/wk) they had spent, on average in the previous year, watching TV, using the computer, studying, participating in manual hobbies, and participating in outdoor activities.

RESULTS

In 2014, 75 students were assessed (15 male and 60 female) with a mean age (mean ± SD) of 19.8 ± 1.6 years (ranging from 18 to 24 years). The mean refractive error M (spherical equivalent) was -0.77 ± 1.79D and the axial length was 23.74 ± 1.19 mm. The prevalence of myopia was 41.3% (31 of 75). In 2002, the mean refractive error M was 0.01 ± 1.53D, the axial length was 23.40 ± 0.93 mm, and the myopia prevalence was 23.4% (26 of 111). The differences between myopia prevalence and mean refractive error are statistically significant (p < 0.05). A statistically significant increase in the number of hrs/wk spent on near activities (p < 0.05) was found.

CONCLUSIONS

In 12 years, the prevalence of myopia among first-year university students at the School of Sciences of the University of Minho rose from 23.4 to 41.3%. This increase in myopia prevalence could be related to the lifestyle changes of the studied population.

Morphological and clinical characteristics of myopic posterior staphyloma in Caucasians

PURPOSE

We aimed to study the morphological characteristics of myopic posterior staphyloma in Caucasians and to evaluate the correlation between posterior staphyloma, myopic macular lesions and visual acuity.

METHODS

Ninety eyes of 67 consecutive patients affected by high myopia associated with posterior staphyloma were recruited between January 2012 and December 2013. Posterior staphyloma was classified according to Curtin's criteria. Every patient underwent fundoscopic examination and best corrected visual acuity measurement (BCVA). A and B-scan ultrasound (US), high-resolution, three-dimensional magnetic resonance image (MRI), optical coherence tomography (OCT), fundus autofluorescence (FAF), red free (RF) and color fundus photography studies were performed.

RESULTS

The mean age was 64.4 ± 9.48 years (range: 41-82). The mean BCVA was 0.7 ± 0.5 logMAR (range: 0-2). The mean axial length was 29.92 ± 2.39 millimeters (range: 24.25-36.53). The authors found four types of posterior staphyloma according to Curtin's classification: I, II, IV and IX. Significant prevalence of posterior staphyloma in female sex was observed (p = 0.0235). Significant correlation between the depth and the diameters of posterior staphyloma was demonstrated (p < 0.0001). Significant association between posterior staphyloma type and tomographic foveal patterns (p = 0.0230) was highlighted. Posterior staphyloma type I was more frequently associated with peripapillary atrophy and less with macular atrophy compared to type II and IX (p = 0.0169). The prevalence of macular atrophy was more than double in posterior staphyloma type II (33.3 %) in comparison to posterior staphyloma type I (12.5 %).

CONCLUSIONS

This study confirms that the type I and II are the most common types of posterior staphyloma, as already highlighted in the literature. A significant association between the type of posterior staphyloma and the MRI ocular shape pattern, the OCT patterns of macular profile and the location of chorioretinal atrophy was highlighted. The correlation between the depth and the width of posterior staphyloma has demonstrated that the deeper the staphyloma, the wider it was. The deepest area of the posterior staphyloma was characterized by a greater thinning of the sclera and by a higher prevalence of chorioretinal atrophy compared to the other parts of the eye. More studies are necessary to support our findings and to add more information on the natural evolution of posterior staphyloma and on its associated complications.

Laser-assisted subepithelial keratectomy (LASEK) versus photorefractive keratectomy (PRK) for correction of myopia

BACKGROUND

Myopia (near-sightedness or short-sightedness) is a condition in which the refractive power of the eye is greater than required. The most frequent complaint of people with myopia is blurred distance vision, which can be eliminated by conventional optical aids such as spectacles or contact lenses, or by refractive surgery procedures such as photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK). PRK uses laser to remove the corneal stroma. Similar to PRK, LASEK first creates an epithelial flap and then replaces it after ablating the corneal stroma. The relative benefits and harms of LASEK and PRK, as shown in different trials, warrant a systematic review.

OBJECTIVES

The objective of this review is to compare LASEK versus PRK for correction of myopia by evaluating their efficacy and safety in terms of postoperative uncorrected visual acuity, residual refractive error, and associated complications.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision group Trials Register) (2015 Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2015), EMBASE (January 1980 to December 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to December 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 December 2015. We used the Science Citation Index and searched the reference lists of the included trials to identify relevant trials for this review.

SELECTION CRITERIA

We included in this review randomized controlled trials (RCTs) comparing LASEK versus PRK for correction of myopia. Trial participants were 18 years of age or older and had no co-existing ocular or systemic diseases that might affect refractive status or wound healing.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all reports and assessed the risk of bias of trials included in this review. We extracted data and summarized findings using risk ratios and mean differences. We used a random-effects model when we identified at least three trials, and we used a fixed-effect model when we found fewer than three trials.

MAIN RESULTS

We included 11 RCTs with a total of 428 participants 18 years of age or older with low to moderate myopia. These trials were conducted in the Czech Republic, Brazil, Italy, Iran, China, Korea, Mexico, Turkey, USA, and UK. Investigators of 10 out of 11 trials randomly assigned one eye of each participant to be treated with LASEK and the other with PRK, but did not perform paired-eye (matched) analysis. Because of differences in outcome measures and follow-up times among the included trials, few trials contributed data for many of the outcomes we analyzed for this review. Overall, we judged RCTs to be at unclear risk of bias due to poor reporting; however, because of imprecision, inconsistency, and potential reporting bias, we graded the quality of the evidence from very low to moderate for outcomes assessed in this review.The proportion of eyes with uncorrected visual acuity of 20/20 or better at 12-month follow-up was comparable in LASEK and PRK groups (risk ratio (RR) 0.98, 95% confidence interval (95% CI) 0.92 to 1.05). Although the 95% CI suggests little to no difference in effect between groups, we judged the quality of the evidence to be low because only one trial reported this outcome (102 eyes). At 12 months post treatment, data from two trials suggest no difference or a possibly small effect in favor of PRK over LASEK for the proportion of eyes achieving ± 0.50 D of target refraction (RR 0.93, 95% CI 00.84 to 1.03; 152 eyes; low-quality evidence). At 12 months post treatment, one trial reported that one of 51 eyes in the LASEK group lost one line or more best-spectacle corrected visual acuity compared with none of 51 eyes in the PRK group (RR 3.00, 95% CI 0.13 to 71.96; very low-quality evidence).Three trials reported adverse outcomes at 12 months of follow-up or longer. At 12 months post treatment, three trials reported corneal haze score; however, data were insufficient and were inconsistent among the trials, precluding meta-analysis. One trial reported little or no difference in corneal haze scores between groups; another trial reported that corneal haze scores were lower in the LASEK group than in the PRK group; and one trial did not report analyzable data to estimate a treatment effect. At 24 months post treatment, one trial reported a lower, but clinically unimportant, difference in corneal haze score for LASEK compared with PRK (MD -0.22, 95% CI -0.30 to -0.14; 184 eyes; low-quality evidence).

AUTHORS' CONCLUSIONS

Uncertainty surrounds differences in efficacy, accuracy, safety, and adverse effects between LASEK and PRK for eyes with low to moderate myopia. Future trials comparing LASEK versus PRK should follow reporting standards and follow correct analysis. Trial investigators should expand enrollment criteria to include participants with high myopia and should evaluate visual acuity, refraction, epithelial healing time, pain scores, and adverse events.

Global variations and time trends in the prevalence of childhood myopia, a systematic review and quantitative meta-analysis: implications for aetiology and early prevention

The aim of this review was to quantify the global variation in childhood myopia prevalence over time taking account of demographic and study design factors. A systematic review identified population-based surveys with estimates of childhood myopia prevalence published by February 2015. Multilevel binomial logistic regression of log odds of myopia was used to examine the association with age, gender, urban versus rural setting and survey year, among populations of different ethnic origins, adjusting for study design factors. 143 published articles (42 countries, 374 349 subjects aged 1–18 years, 74 847 myopia cases) were included. Increase in myopia prevalence with age varied by ethnicity. East Asians showed the highest prevalence, reaching 69% (95% credible intervals (CrI) 61% to 77%) at 15 years of age (86% among Singaporean-Chinese). Blacks in Africa had the lowest prevalence; 5.5% at 15 years (95% CrI 3% to 9%). Time trends in myopia prevalence over the last decade were small in whites, increased by 23% in East Asians, with a weaker increase among South Asians. Children from urban environments have 2.6 times the odds of myopia compared with those from rural environments. In whites and East Asians sex differences emerge at about 9 years of age; by late adolescence girls are twice as likely as boys to be myopic. Marked ethnic differences in age-specific prevalence of myopia exist. Rapid increases in myopia prevalence over time, particularly in East Asians, combined with a universally higher risk of myopia in urban settings, suggest that environmental factors play an important role in myopia development, which may offer scope for prevention.

A 12-year review on the aetiology and surgical outcomes of paediatric rhegmatogenous retinal detachments in Hong Kong

PURPOSE

To evaluate the aetiology, clinical features, and surgical outcomes of paediatric rhegmatogenous retinal detachments (RRD) in Hong Kong.Patients and methodsThis is a retrospective consecutive case series of all patients aged 18 or under who underwent primary retinal detachment repair in the Hong Kong Eye Hospital from January 2000 to December 2012.ResultsForty-nine eyes of 47 patients were included. The mean age was 14, and the mean follow-up duration was 6.2 years. The most common aetiology for RRD was idiopathic (28.6%), followed by high myopia (24.5%), atopic dermatitis (AD) (18.4%), congenital and developmental abnormalities (16.3%), trauma (8.2%), and intraocular inflammation (4.1%). The mean preoperative visual acuity was LogMAR 1.0±0.8 (Snellen equivalent 6/60). The primary anatomical success rate in this series was 65.3%, and the final anatomical success rate was 85.7%. The mean postoperative visual acuity was LogMAR 0.9±1.2 (Snellen equivalent 6/48). Patients with congenital and developmental abnormalities or AD had worse anatomical and functional outcomes than patients who had no predisposing factor or high myopia.

CONCLUSIONS

The primary and overall anatomical success rates in our series were comparable with existing literature. High myopia is the most commonly identifiable risk factor in Hong Kong and AD is associated with a higher re-detachment rates and a poor visual outcome.

Investigating the choriocapillaris and choroidal vasculature with new optical coherence tomography technologies

The body of knowledge of in vivo investigation of the choroid has been markedly enhanced by recent technological advances in optical coherence tomography (OCT). New insights elucidating the morphological features of the choriocapillaris and choroidal vasculature, in both physiological and pathological conditions, indicate that the choroid plays a pivotal role in many posterior segment diseases. In this article, a review of the histological characteristics of the choroid, which must be considered for the proper interpretation of in vivo imaging, is followed by a comprehensive discussion of fundamental principles of the current state-of-the-art in OCT, including cross-sectional OCT, en face OCT, and OCT angiography using both spectral domain OCT and swept source OCT technologies. A detailed review of the tomographic features of the choroid in the normal eye is followed by relevant findings in prevalent chorioretinal diseases, focusing on major causes of vision loss such as typical early and advanced age-related macular degeneration, polypoidal choroidal vasculopathy, central serous chorioretinopathy, pachychoroid spectrum disorders, diabetic choroidopathy, and myopia.

The Association between Maternal Reproductive Age and Progression of Refractive Error in Urban Students in Beijing

Purpose

To investigate the association between maternal reproductive age and their children’ refractive error progression in Chinese urban students.

Methods

The Beijing Myopia Progression Study was a three-year cohort investigation. Cycloplegic refraction of these students at both baseline and follow-up vision examinations, as well as non-cycloplegic refraction of their parents at baseline, were performed. Student’s refractive change was defined as the cycloplegic spherical equivalent (SE) of the right eye at the final follow-up minus the cycloplegic SE of the right eye at baseline.

Results

At the final follow-up, 241 students (62.4%) were reexamined. 226 students (58.5%) with completed refractive data, as well as completed parental reproductive age data, were enrolled. The average paternal and maternal age increased from 29.4 years and 27.5 years in 1993–1994 to 32.6 years and 29.2 years in 2003–2004, respectively. In the multivariate analysis, students who were younger (β = 0.08 diopter/year/year, P<0.001), with more myopic refraction at baseline (β = 0.02 diopter/year/diopter, P = 0.01), and with older maternal reproductive age (β = -0.18 diopter/year/decade, P = 0.01), had more myopic refractive change. After stratifying the parental reproductive age into quartile groups, children with older maternal reproductive age (trend test: P = 0.04) had more myopic refractive change, after adjusting for the children's age, baseline refraction, maternal refraction, and near work time. However, no significant association between myopic refractive change and paternal reproductive age was found.

Conclusions

In this cohort, children with older maternal reproductive age had more myopic refractive change. This new risk factor for myopia progression may partially explain the faster myopic progression found in the Chinese population in recent decades.