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As the population ages, promoting good health maintenance practices has become an important strategy in many health systems. Regular general health checks detect common diseases and empower older adults to monitor their physical health. Yet the service uptake rate is low. Previous reviews have identified intervention methods to improve the uptake rate, but the overall effectiveness of these interventions remains unclear. This review aims to determine the overall effectiveness of the interventions used to improve general health check uptake and identify the behavior change techniques used in these interventions. Literature searches were conducted in four electronic databases in August 2020 and updated in May 2021. Six randomized controlled trials were included in this review. Seven intervention types were identified, including enhanced invitation letters, telephone invitation, question-behavior-effect questionnaire, financial incentive, leaflet, pre-notification, and SMS reminder. Overall, the interventions are effective, with an odds ratio of 1.21, and a 95% confidence interval between 1.09–1.33. Fifteen behavior change techniques were identified using the Behaviour Change Technique Taxonomy (v1). The findings suggest that the current interventions implemented in invitation methods are effective in improving the general health check uptake rate, but there are still opportunities to further improve the uptake rate by considering other intervention types. Future studies could consider how other intervention types could be implemented alone or with the enhanced invitation methods to maximize the service uptake rate. The systematic review protocol is registered on PROSPERO (ref: CRD42021221041).

Background Visual decline is inevitable in older adults. Utilizing preventive vision care can mitigate major risk factors, yet the uptake rate remains suboptimal globally. Barriers to seek preventive eye care were identified in the literature. However, the understanding of these barriers was limited by the quantitative approach, hindering the opportunity to suggest specific strategies to improve service uptake. This qualitative aimed to identify the factors influencing the decision-making process of older adults to use preventive vision care. Methods This was a qualitative study guided by the grounded theory approach. Purposive sampling was used to recruit the subjects. Semi-structured interviews were conducted with 25 community-dwelling adults aged 65 years or above in Hong Kong. Data were transcribed and constant comparison techniques were used for data analysis. Results The core theme revealed a decision-making process of being difficult in “prioritising and fitting preventive vision care into the existing health service utilization” for older people when deciding the utilization of preventive vision care. Five sub-themes were identified to explain the low preventive vision care utilization. Specifically, in absence of past preventive vision care utilization experience, most rely on other “previous health service utilization” to guide their judgment. “Low perceived preventive vision care needs” were due to perceived low disruption of symptoms in daily practices and lack of social cues. “Low perceived self-efficacy of service utilization” was due to limited information on service availability, limited social support, limited health literacy, and financial concerns. Unfulfilled “service expectation” also lowered their motivation to use preventive vision care. Discussion This study found that multiple factors influenced the decision-making process and reduced the motivation of subjects to use preventive vision care. Future interventions could exploit the benefit of social influences on the identified factors so that preventive vision care can smoothly fit into the ongoing healthcare use. Adopting a longitudinal qualitative perspective would enrich understanding the reasons for not using preventive vision care.

Understanding the impact of a health care voucher scheme and service access barriers could facilitate optometry service promotion to the older population.A voucher is one strategy to improve the utilisation of the different health care services available in the private sector. This study aims to explore how a health care voucher system for older people impacts utilisation of optometry services from the perspective of service users and service providers.People aged 65 years or above were recruited to fill in a structured questionnaire studying the usage characteristics and access barriers of optometry services and the health care voucher. Views from the optometrists about the voucher scheme were collected by questionnaire.A total of 1156 valid questionnaires from eligible voucher users was collected. Results showed that 53.7% (621/1156) of participants had used optometry services within the past 2 years. Lack of familiarity with services provided, professional fees, and prices of spectacles were the main barriers to using optometry services. Of those participants who had used the voucher for optometry services previously, 80.4% (284/353) had an eye examination in the past 2 years. Among 389 optometrists who participated in the study, over 80% agreed that the voucher scheme improved awareness of major eye conditions and access to prescription spectacles when necessary.The health care voucher for older people improved access to optometry services. Access could be further improved by increasing price transparency of professional services and prescription spectacles. Responses from optometry service providers supported the view that the voucher scheme improved access to, and utilisation of, preventive care services.

Background Financial incentive is increasingly used as a mean to promote preventive care utilization (PCU), but the current Elderly Health Care Voucher Scheme (EHCVS) in Hong Kong is ineffective for encouraging PCU. Objective To explore the older people's barriers to PCU and their views on financial incentive, including EHCVS, for improving private PCU. Design and setting Focus-group discussions were conducted in community elderly centres located in five districts of Hong Kong. Participants Community-dwelling older people aged 60 years or above. Results Lack of understanding about preventive care and low awareness of the need for preventive care were key factors for the low motivation for PCU. Uncertainty over the level of service fee charged and concerns over service quality hindered the choice of using the private service providers under the current EHCVS. Financial incentives specific for preventive care services were thought to be cues to actions and guides for service promotion. However, some flexibility in service coverage and a set time limit of the financial incentives were preferred to accommodate individual needs. Conclusions Apart from promoting knowledge of preventive care, official monitoring for service fee and quality is important for empowering older people to choose private service providers for preventive care. Financial incentives for preventive care services should be more specific to cue service promotion and uptake of preventive care while maintaining flexibility to accommodate individual needs. Patient or public contribution Participants were recruited using purposive sampling with the coordination of community elderly centres. Data were analysed using thematic coding.

Myopia is the commonest eye disorder in the world. High myopes are predisposed to ocular pathologies. The vasoactive intestinal peptide receptor 2 (VIPR2) gene was identified as a myopia susceptibility locus by our group and another group. We continued to fine-map this locus. A case-control study was performed in 4 sequential stages with a total of 941 highly myopic subjects and 846 control subjects, all unrelated Chinese. Stage 1 experimentally genotyped 64.4% of the entire cohort for 152 single-nucleotide polymorphisms (SNPs) and Stage 2 the remaining subjects for 21 SNPs. Stage 3 combined the genotypes for 21 SNPs for the entire cohort, and identified one group of high-risk haplotypes and one group of protective haplotypes significantly associated with high myopia. Stage 4 imputed genotypes for variants in the VIPR2 region and identified two independent groups of variants: one group with high-risk minor alleles and another with protective minor alleles. Variants within each group were generally in strong linkage disequilibrium among themselves while high-risk variants were in linkage equilibrium with protective variants. Therefore, the VIPR2 locus seems to contain variants with opposite effects. This is the first study that has examined the genetic architecture of a myopia susceptibility locus in detail.

ObjectiveThis study was conducted to evaluate the real-world effectiveness and potential cost-effectiveness of a community-based vision care programme for the ageing population aged 60 years or above.MethodsData from a total of 8899 subjects participating in a community based comprehensive vision care programme from 2015 to 2019 were extracted and analyzed to evaluate the effectiveness of the programme in terms of the prevalence of visual impairment (VI), the change in the prevalence of VI after refractive error correction, and the types of ocular disorders detected. VI was defined by a) visual acuity (VA) worse than 6/18 in any eye (worse eye) and b) VA worse than 6/18 in the better eye. The cost-effectiveness from the funder’s perspective was also estimated in terms of cost per VI avoided from such a programme.ResultsThe study found that referenced to VA of the worse eye, the prevalence of VI was 39.1% (3482/8899, 95% CI: 38.1%-40.1%) based on presenting VA and reduced to 13.8% (1227/8899, 95% CI: 13.1%-14.5%) based on best-corrected VA. Referenced to the VA in the better eye, the prevalence of VI was 17.3% (1539/8899, 95% CI: 16.5%-18.1%) based on presenting VA and decreased to 4.2% (373/8899, 95% CI: 3.8%-4.6%) after best-corrected VA. Uncorrected refractive error was the major cause of presenting VI. From the funder’s perspective, the cost per VI case prevented was HK$1921 based on VA in the worse eye and HK$3715 based on the better eye.ConclusionA community-based programme was effective to detect the VI and reduced a relative 65% to 76% VI after refractive error correction for the community-dwelling ageing population. The ageing population can benefit from regular comprehensive vision care.

PURPOSE To evaluate the influence of 2.2 mm clear corneal incision (CCI) features in surgically induced astigmatism (SIA) and higher-order aberrations (HOAs) after cataract surgery. METHODS Right eyes of 92 subjects receiving 2.2 mm incision cataract surgery were involved. A total of 38 eyes were categorized as the intact incision group, and 54 eyes were the defective incision group. Pre- and postoperative (1 month and 6 months) corneal astigmatism and HOAs on anterior and posterior corneal surfaces, corneal volume, and corneal thickness (CT) were measured using Pentacam. The CCI features including incision length (IL), incision angles, distance from incision to central cornea (Dis-En/Ex), and CT at incision site were quantified using AS-OCT. RESULTS The defective incision group showed shorter IL and larger incision angles [false discovery rate (FDR) - p

Purpose The SARS‐CoV‐2 RNA has been detected in tears and conjunctival samples from infected individuals. Conjunctivitis is also reported in a small number of cases. We evaluated ocular symptoms and ocular tropism of SARS‐CoV‐2 in a group of patients with COVID‐19. Method Fifty‐six patients infected with SARS‐CoV‐2 were recruited as subjects. Relevant medical histories were obtained from the electronic medical record system. Ocular history and ocular symptoms data were obtained by communicating directly with the subjects. The Ocular Surface Disease Index (OSDI) and Salisbury Eye Evaluation Questionnaire (SEEQ) were used to assess the anterior ocular surface condition before and after the onset of disease. Results Patients classified as severe COVID‐19 cases were more likely to have hypertension compared to mild cases (p = 0.035). Of the 56 subjects, thirteen patients (23%) were infected in Wuhan, 32 patients (57%) were community‐infected, 10 patients (18%) were unknown origin, 1 (2%) was a physician likely infected by a confirmed patient. Three patients wore face mask with precaution when contacting the confirmed patients. Fifteen (27%) had aggravated ocular symptoms, of which 6 (11%) had prodromal ocular symptoms before disease onset. The differences in mean scores of OSDI questionnaire and SEEQ between before and after onset of COVID‐19 were all significant (p

ObjectiveTo study how a non-targeted publicly-funded health care voucher system for the elderly impact on access to optometry services from the perspective of service users and service providersDesignCross-sectional studySetting19 elderly community centersParticipants1176 people, aged 65 years or above, and 389 optometristsPrimary and secondary outcome measuresUsage characteristics of optometry services by eligible service users of the voucher schemePerspectives of eligible service users on access barriers to optometry servicesPerspectives of service providers on voucher schemeResultsIn total, 1156 valid questionnaires were collected from a cohort of eligible service users. Results showed that 53.7% of subjects had used optometry services within the past 2 years, while 22% had not used optometry services before. Lack of familiarity with services provided, professional fees and prices of prescription spectacles were the main barriers to using optometry services. Of those subjects who had used the voucher for optometry service before, 80.4% had eye examination in the past 2 years, versus 64.1% among subjects who had not use health care voucher on the optometry service. “Insufficient voucher value” was a commonly quoted reason for not using the health care vouchers for optometry services. Over 80% of optometrists agreed that the voucher scheme improved the awareness of major eye conditions and enabled the elderly to have prescription spectacles when necessary.ConclusionThe health care voucher for the elderly improved access to optometry services. Access could be improved further by promoting awareness optometry services, location of service providers, price transparency of professional services and prescription spectacles. Responses from optometry services providers are supportive of the view that the voucher scheme improved access to and utilization of preventive care services.Article SummaryStrengths and limitations of this study-High representativeness of community dwelling older population in Hong Kong.-The mixed method approach provided a more in-depth investigation of the population.-One limitation is the generalizability of the results with older people who are members in the community centers.

Background: Coronavirus disease 2019 (COVID-19) is a highly infectious disease transmitted human-to-human by the coronavirus SARS-CoV-2 The SARS-CoV-2 RNA has

To evaluate the risk factors associated with contamination of lens cases in a group of orthokeratology (ortho-k) lens wearers.Ortho-k patients attending the Contact Lens Clinic of the Hospital were required to complete a checklist about their routine daily care and handling of lens cases. Their cases were then collected for analysis. Contamination was evaluated by determining the optical density (OD) of crystal violet stained biofilm present in the cases. OD values were divided into three groups, lower, middle, and upper tertiles, and associations between risk factors were determined by multivariate analysis.A total of 194 subjects were recruited. Twenty-five subjects used cylindrical lens cases (CC), 98 flat cases with ridges (FCR), and 71 flat cases without ridges (FC). FCRs were the most heavily contaminated and CC showed least contamination (FCR FC, OR 2.16, CI 1.11-4.18, p = 0.023; FCRCC, OR 8.86, CI 2.97-26.44, p0.001; FC CC, OR 2.33, CI 1.35-12.45, p = 0.013). Replacing lens cases monthly significantly reduced the risk of high contamination (OR 0.013, CI 0.06-0.30, p 0.001), compared to those used for three months. Cases that were not rinsed (OR 3.44, CI 1.50-7.86, p = 0.003) or rinsed by other methods (OR 4.07, CI 1.67-9.92, p = 0.002) had significantly more contamination, compared to those rinsed with multipurpose solution. Lens cases, which were not dried (OR 11.36, CI 2.06-62.93, p = 0.005) or air-dried (OR 8.71, CI 1.16-65.56, p = 0.036), showed more contamination compared to those wiped with tissue daily.Case design (cylindrical), monthly replacement, daily rinsing with MPS, and wiping with tissue daily can effectively reduce biofilm formation in contact lens cases.

Background Genome-wide association studies (GWAS) is a major method for studying the genetics of complex diseases. Finding all sequence variants to explain fully the aetiology of a disease is difficult because of their small effect sizes. To better explain disease mechanisms, pathway analysis is used to consolidate the effects of multiple variants, and hence increase the power of the study. While pathway analysis has previously been performed within GWAS only, it can now be extended to examining rare variants, other “-omics” and interaction data. Scope of review 1. Factors to consider in the choice of software for GWAS pathway analysis. 2. Examples of how pathway analysis is used to analyse rare variants, other “-omics” and interaction data. Major conclusions To choose appropriate software tools, factors for consideration include covariate compatibility, null hypothesis, one- or two-step analysis required, curation method of gene sets, size of pathways, and size of flanking regions to define gene boundaries. For rare variants, analysis performance depends on consistency between assumed and actual effect distribution of variants. Integration of other “-omics” data and interaction can better explain gene functions. General significance Pathway analysis methods will be more readily used for integration of multiple sources of data, and enable more accurate prediction of phenotypes.

Identification of genetic variations related to high myopia may advance our knowledge of the etiopathogenesis of refractive error. This study investigated the role of potassium channel gene (KCNQ5) polymorphisms in high myopia. We performed a case-control study of 1563 unrelated Han Chinese subjects (809 cases of high myopia and 754 emmetropic controls). Five tag single-nucleotide polymorphisms (SNPs) of KCNQ5 were genotyped, and association testing with high myopia was conducted using logistic regression analysis adjusted for sex and age to give Pasym values, and multiple comparisons were corrected by permutation test to give Pemp values. All five noncoding SNPs were associated with high myopia. The SNP rs7744813, previously shown to be associated with refractive error and myopia in two GWAS, showed an odds ratio of 0.75 (95% CI 0.63–0.90; Pemp = 0.0058) for the minor allele. The top SNP rs9342979 showed an odds ratio of 0.75 (95% CI 0.64–0.89; Pemp = 0.0045) for the minor allele. Both SNPs are located within enhancer histone marks and DNase-hypersensitive sites. Our data support the involvement of KCNQ5 gene polymorphisms in the genetic susceptibility to high myopia and further exploration of KCNQ5 as a risk factor for high myopia.

Purpose To determine the prevalence and risk factors of myopia-related retinal changes in Hong Kong Chinese adolescents with high myopia. Methods A cross-sectional study on Hong Kong Chinese teenage subjects with high myopia was conducted between January 2005 and June 2009. Subjects were recruited via newspaper advertisements, invitation letters to schools, leaflets and posters. Data collected included history related to myopia progression and retinal characteristics. Results In total, 120 subjects (61 boys and 59 girls) were recruited. The mean age was 14.8 ± 1.6 years (range: 12–18 years). The mean SER of the eyes was −8.41 ± 1.60 D. Ninety four of the 120 adolescents were found to have a retinal change of which 0.8% were sight-threatening, 2.5% were posterior pole changes, and 61.7% were peripheral retinal changes. The five most frequent retinal changes found were optic nerve crescents (52.5%), white-without-pressure (51.7%), lattice degeneration (5.8%), microcystoid degeneration (5%) and pigmentary degeneration (4.2%). After adjusting for myopia over −8 D, age, gender, duration of myopia, family retinal history and intraocular pressure (IOP), binary logistic regressions showed that an axial length longer than 26.5 mm was a significant risk factor for peripheral retinal changes, optic nerve crescents and white-without-pressure. Conclusions Peripheral retinal degenerative changes and optic nerve crescent were found in a significant proportion of high myopic teenage subjects. There is increased risk of retinal changes in eyes with an axial length >26.5 mm in 12–18 year-olds.

Purpose Myopia is a complex eye disorder. The X-linked form of complete congenital stationary night blindness (CSNB1A) is usually associated with moderate to high myopia, and is caused by mutations in the NYX gene. We explored if NYX mutations could be associated with high myopia, but not CSNB1A. Methods The coding regions of the NYX gene were sequenced for 204 Chinese males with high myopia (−8.00 dioptres or worse for both eyes). The frequencies of any sequence variations identified were determined in 200 Chinese males without myopia. Electro-oculography, electroretinography and standard cone function tests were performed on a male high myope carrying a mutation. Results A missense mutation (c.529_530GC>AT or p.Ala177Met) was identified in one male subject with high myopia, but not in 200 male emmetropes. Neither was this variant found in any of the 529 male and 567 female subjects of various ethnic backgrounds whose genome sequences are documented in the 1000 Genomes Project database. The mutation was predicted to affect the protein function. From ocular electrophysiological tests, the proband was found to have normal rod function, but mildly abnormal cone function and inner retina function. He did not seem to suffer from CSNB1A. Conclusions One novel missense NYX mutation was identified in an adult male presented with high myopia, but without the major electrophysiological features normally associated with CSNB1A. NYX gene mutations may be considered as one of the rare genetic risk factors for high myopia without key features of CSNB1A.

Purpose Acanthamoeba keratitis (AK), which is associated with noncompliant use of contact lenses, remains difficult to treat due to delayed diagnosis and paucity of therapeutic agents. Although improvements in activity against Acanthamoeba infection have been achieved in disinfecting solutions for soft contact lenses, such modifications have not been extended to those for special rigid gas permeable (RGP) contact lenses, which are increasingly used for myopia control in children. Phytochemicals present in herbs used for traditional Chinese medicine may be effective as therapeutic or preventive agents. The purpose of this study was to investigate amoebicidal properties of lead phytochemicals of Radix scutellariae alone and in combination with multipurpose (disinfecting) solutions (MPS) for RGP lenses. Methods Viability of Acanthamoeba castellani and A. polyphaga trophozoites was determined following exposure to four phytochemicals: baicalin, baicalein, wogonoside, and oroxylin A and both alone and in combination with four RGP MPS, using a modified stand-alone technique. Results As individual agents, wogonoside and oroxylin A showed highest activity against A. castellani and A. polyphaga trophozoites, respectively. For both organisms, the combination of baicalein and oroxylin A was superior. Effectiveness of MPS alone did not exceed 0.27 log reduction, but addition of combined baicalein and oroxylin A resulted in 0.92 and 0.64 log reductions of A. castellani and A. polyphaga, respectively. Conclusions The combination of baicalein and oroxylin A enhanced the activity of MPS for RGP contact lenses against trophozoites of two pathogens, A. castellani, and A. polyphaga, and offers a potential therapeutic and/or preventative agent for AK.

To investigate the interocular symmetry of optical, biometric, and biomechanical characteristics between the fellow eyes of myopic anisometropes.Thirty-four young, healthy myopic anisometropic adults (≥ 1 D spherical equivalent difference between eyes) without amblyopia or strabismus were recruited. A range of biometric and optical parameters were measured in both eyes of each subject including axial length, ocular aberrations, intraocular pressure, corneal topography, and biomechanics. Ocular sighting dominance was also measured.Mean absolute spherical equivalent anisometropia was 1.70 ± 0.74 D, and there was a strong correlation between the degree of anisometropia and the interocular difference in axial length (r = 0.81, p0.001). The more and less myopic eyes displayed a high degree of interocular symmetry for the majority of biometric, biomechanical, and optical parameters measured. When the level of anisometropia exceeded 1.75 D, the more myopic eye was more likely to be the dominant sighting eye than for lower levels of anisometropia (p = 0.002). Subjects with greater levels of anisometropia (1.75 D) also showed high levels of correlation between the dominant and non-dominant eyes in their biometric, biomechanical, and optical characteristics.Although significantly different in axial length, anisometropic eyes display a high degree of interocular symmetry for a range of anterior eye biometrics and optical parameters. For higher levels of anisometropia, the more myopic eye tends to be the dominant sighting eye.

Purpose: To investigate the retinal thickness profile in myopic and non-myopic eyes. Methods: The retinal thickness profile of 30 myopic eyes [spherical equivalent error (SER) between −6.00 and −13.63 D] and 31 non-myopic eyes (SER between +2.75 and −0.50 D) were measured using the Stratus OCT (Carl Zeiss Meditec, Dublin, CA, USA). Two scan types were used: the Macular Thickness Map and the Customized Line Scan for a central 80° horizontal retinal thickness profile. Results: At foveal center and fovea, myopic eyes had a thicker retina than the non-myopic group (p = 0.002 and 0.044, respectively). At other zones of the macula, the retina was significantly thinner in myopic eyes compared to non-myopic eyes (p

Objective To assess the association between awareness of diabetic retinopathy (DR) and actual attendance for DR screening. Design Cross-sectional study. Setting Two public general outpatient clinics. Participants The subjects were people with diabetes mellitus (DM) who participated in a randomised controlled trial, set up in 2008, to test the impact of a copayment on attendance for DR screening. Primary and secondary outcome measures The subjects’ awareness of DR was evaluated using a structured questionnaire conducted via a telephone interview. The attendance for screening was from the actual attendance data. Association between awareness and attendance for screening was determined using multivariate logistic regression model and was reported as ORs. Results A total of 2593 participants completed the questionnaire. A total of 42.9% (1113/2593) said they would worry if they had any vision loss and 79.6% (2063/2593) knew that DM could cause blindness. Only 17.5% (453/2593) knew that treatment was available for DR and 11.5% (297/2593) knew that early DR could be asymptomatic. The importance of having a regular eye examination was acknowledged by 75.7% (1964/2593), but 34% (881/2593) did not know how frequently their eyes should be examined. Worry about vision loss (OR=1.72, P

In a prospective study, designed to test the effect of intraocular lenses containing an ultraviolet absorbing chromophore on the incidence of post-operative cystoid macular oedema, 55 patients undergoing extracapsular cataract extraction were randomly allocated to receive intraocular lenses with or without an ultra-violet absorbing chromophore. Post-operative fluorescein angiography showed no difference in the incidence of macular oedema in those patients receiving an intraocular lens with an ultraviolet absorbing chromophore compared with patients receiving a standard posterior chamber intraocular lens.

Background: The relationship between monochromatic aberrations of the human eye and myopia has been investigated extensively over the past decade or so but the results are inconclusive. Wide age range, narrow refractive error range and large individual variations are common confounding factors in previous studies. To address these shortcomings, we conducted a two-part study. The first part set out to determine whether the monochromatic aberrations in myopic eyes are different from those in the non-myopic eyes in adults. Subjects were drawn from a narrow age band to minimise the confounding effect of age. The second part of this study compared the monochromatic aberrations of the more myopic and less myopic eyes of anisometropes. Methods: Monochromatic aberrations were measured for 5 mm pupils using the Complete Ophthalmic Analysis System (COAS) Wavefront Analyzer in 116 subjects with refractive spherical equivalent between -10.38 D and +1.38 D and in 26 anisometropes. Measurements were done in a dark room with natural pupils. The refractive errors, corneal curvatures and axial lengths of the eyes were measured under natural accommodation. Results: Highly myopic eyes had significantly smaller root mean square (RMS) values of fourth order (p = 0.015) and spherical aberrations (p = 0.009) than non-myopic eyes. The correlation coefficient was 0.2354 (p = 0.011) between fourth-order aberrations and refractive spherical equivalents and 0.2817 (p = 0.002) between spherical aberration and refractive spherical equivalents. Less myopic eyes of the anisometropes showed significantly larger total higher-order, third-order and spherical aberrations than the more myopic eyes (p < 0.05, p < 0.05 and p < 0.01, respectively). Conclusions: Our study shows that spherical aberration is associated with refractive error. More myopic eyes tended to have smaller amounts of spherical aberration, however, the ‘cause or effect’ question remains. Longitudinal studies are needed to further investigate the relationship between monochromatic aberrations and refractive development.

Background: Optomap uses the ultra-wide field scanning laser ophthalmoscopy to provide retinal examination. It permits fundus examination without the use of a mydriatic, which is more comfortable for the patients. This paper determines the sensitivity and specificity of the Optomap for detecting retinal signs under non-mydriatic conditions.----- Methods: Fifty-four eyes identified with retinal/choroidal signs and eight normal eyes were recruited from 31 Hong Kong Chinese subjects. Photo-documentation of fundal changes was obtained with the Optomap under non-mydriatic conditions before a dilated fundus examination by a clinician using standard procedures. The eyelid was retracted using a cotton bud when necessary. Dilated fundus examinations were performed by another clinician using binocular indirect ophthalmoscopy and slitlamp biomicroscopy with a fundus lens. The Optomap images were evaluated by four other investigators under masked condition. The International Classification of Disease, Ninth Revision (ICD-9-CM) was adopted for recording retinal features. Screening results were compared with those obtained using the dilated fundus examination as the gold standard.----- Results: The cotton bud method for eyelid retraction showed an improvement in the area of retina that could be visualised. The sensitivity and specificity of the Optomap averaged 76.4 and 71.9 per cent, respectively. Some fundal signs were missed by all observers in the Optomap but not with the biomicroscope. These included white-without-pressure, lattice degeneration, paramacular drusen and pigmentary changes at central fundus.----- Conclusion: Optomap serves as a reliable screening tool for fundus examination especially because it covers a much wider area of the peripheral retina than other digital instruments for fundus photography.

We investigated characteristics of multifocal electroretinograms (mfERG) from in vitro perfused porcine eyes. TTX, NMDA, APB, and PDA were used to identify contributions to the mfERG from inner retinal neurons, ON-pathway, OFF-pathway, and photoreceptors. The cellular contributions of the first-order kernel (K1) in an isolated perfused porcine mfERG came from both inner and outer retina, and were similar to those of in vivo porcine mfERG. In addition, application of isoflurane and propofol caused interference with the mfERG response which resembled inner retinal activities sensitive to TTX + NMDA application. Improved understanding of the cellular origins of the perfused porcine mfERG, in the absence of anesthetic agents, is useful for identifying changes shown in the waveform under anesthesia.

The prevalence of myopia is high in many parts of the world, particularly among the Orientals such as Chinese and Japanese. Like other complex diseases such as diabetes and hypertension, myopia is likely to be caused by both genetic and environmental factors, and possibly their interactions. Owing to multiple genes with small effects, genetic heterogeneity and phenotypic complexity, the study of the genetics of myopia poses a complex challenge. This paper reviews the current approaches to the genetic analysis of complex diseases and how these can be applied to the identification of genes that predispose humans to myopia. These approaches include parametric linkage analysis, non-parametric linkage analysis like allele-sharing methods and genetic association studies. Basic concepts, advantages and disadvantages of these approaches are discussed and explained using examples from the literature on myopia. Microsatellites and single nucleotide polymorphisms are common genetic markers in the human genome and are indispensable tools for gene mapping. High throughput genotyping of millions of such markers has become feasible and efficient with recent technological advances. In turn, this makes the identification of myopia susceptibility genes a reality.

The aims were to determine the level of compliance of contact lens wearers, to identify which procedures have highest levels of non-compliance and to study the effectiveness of a compliance enhancement strategy on the level of compliance.The level of compliance for each subject was evaluated with a self-administered questionnaire together with microbiological examination of their contact lenses, lens cases and lens care solutions. The effect of an intervention to improve the level of compliance was determined by a controlled trial. A regular self-review exercise on proper lens handling was given to the test group once every three months for 12 months. The levels of compliance and contamination of contact lenses and lens care accessories between test and control groups were compared at the end of the 12-month period to evaluate the effect of the intervention.Sixty-five subjects who were experienced contact lens wearers were recruited and 60 completed the study. All showed some degree of non-compliance in the care of their contact lenses and lens accessories. Most (about 60 per cent) were non-compliant with at least six of a total of 15 lens care procedures. The most common non-compliant behaviour among contact lens wearers was associated with the care of the lens case. By the end of the study period, our compliance enhancement strategy did not appear to have had a significant effect on the behaviour of our subjects, except for improvement in the care of lens cases. Compliance for other procedures improved in both test and control groups.All subjects showed some degree of non-compliance and the spectrum of non-compliance was wide. The poorest levels of compliance were associated with care of the lens case, which was also the most frequently contaminated item. Our compliance enhancement strategy showed a significant difference in improvement in compliance between the intervention and control groups only in the care of lens cases.

Purpose: This study aimed to examine the rates of microbial contamination, and identify contaminants associated with contact lenses and lens care accessories used by a group of young contact lens wearers. Methods: Collected contact lenses, lens cases, and lens care solutions were studied by bacterial culture. Contamination rates of these samples were recorded and compared with those reported in previous studies. Results: Of the samples tested, 9% of lens extracts, 34% of case extracts and 11% of solution samples were contaminated with ocular pathogenic microorganisms. Serratia spp., Staphylococcus aureus and coagulase-negative staphylococci were the most common microorganisms isolated. Lens cases were the most frequently contaminated item. Lens cases also yielded the widest range of bacterial isolates. Contact lenses used by occasional wearers were associated with a higher contamination rate. Using either saline or multipurpose solution to rinse lenses before use appeared to be effective in reducing incidence of contamination. Conclusion: Our findings demonstrate that contact lenses and lens care accessories are not well maintained by contact lens wearers. Regular reviews and reinforcement of lens care procedures for the usage and care of contact lenses and lens care accessories is therefore important and essential.

The effect of nitric oxide (NO) on aqueous humour formation (AHF) and intraocular pressure (IOP) was studied using NO donors, sodium azide (AZ) and sodium nitroprusside (SNP). Using the porcine arterially perfused eye preparation, drug effects on AHF and IOP were measured by fluorescein dilution and manometry, respectively. Perfusion pressure of the ocular vasculature was also monitored using digital pressure transducer and pen recorder. L-Arginine (1.0 mM), a precursor of NO, but not D-arginine (1.0 mM), the inactive analogue, produced a significant reduction in AHF (28.5%) and IOP (21.1%). L-NAME (L-nitro-L-arginine) (10–100 μM), an NO synthase inhibitor, had no effect on AHF and IOP. However, L-NAME (100 μM) completely reversed L-arginine's effect. AZ and SNP reduced the AHF and IOP dose-dependently. AZ at 100 nM, 1 and 10 μM reduced AHF by 26.0, 39.7 and 51.7% and IOP by 10.8, 17.3 and 24.0%, respectively. SNP at 1, 10 and 100 μM reduced the AHF by 6.0, 24.2 and 35.4% and IOP by 3.5, 9.5 and 15.5%, respectively. 8-pCPT-cGMP (8-para-chlorophenyl-thioguanosine-3′,5′-cyclic guanosine monophosphate, 10 μM), a cGMP analogue, also reduced the AHF (34.9%) and IOP (15.9%). The effects of AZ and SNP on the AHF and IOP were blocked by a soluble guanylate cyclase inhibitor ODQ (10 μM), whereas ODQ alone or combined with 8-pCPT-cGMP had no effect on the AHF and IOP. None of the drugs had any significant effect on ocular vasculature. The reduction of the AHF and IOP in the arterially perfused pig eye by nitrovasodilators is likely to involve the NO-cGMP pathway. Keywords: Aqueous humour formation, cGMP, intraocular pressure, NO donors, pig eye Introduction Nitric oxide (NO) is an important biomolecule responsible for many biological activities. It is widely believed that the biological effects of NO donors, such as nitrovasodilators, are due to the release of NO which activates soluble guanylate cyclase (sGC) (Feelisch & Noack, 1987). The biological functions of NO are so diverse that it has been described as a second messenger, autocrine, paracrine, neurotransmitter, hormonal (Murad, 1998), cytoprotective (Wang et al., 2002) and a cytotoxic (Kroncke et al., 1997) agent. The role of NO has been studied extensively in many tissues including the eye. (Chiou, 2001) Although many have reported that NO donors reduce intraocular pressure (IOP) in normal and glaucomatous animals (Nathanson, 1992; Schuman et al., 1994; Wang & Podos, 1995) and human (Chuman et al., 2000), the exact effect of NO on the aqueous humour (AH) flow remains unclear. Owing to the dominant role of NO in vasodilatation and relaxation of smooth muscle, attention has been given mostly to ocular blood flow (Schmetterer & Polak, 2001) or trabecular meshwork and ciliary muscle relaxation (Wiederholt et al., 1994) and AH outflow (Schuman et al., 1994; Behar-Cohen et al., 1996). In those studies that have reported on the role of NO on AH outflow and IOP, data are conflicting. Some studies showed that both topical and intraocular administration of NO donors reduced the IOP (Nathanson, 1992; Behar-Cohen et al., 1996; Kotikoski et al., 2003b), but others reported that topical NO donors increased IOP without affecting aqueous humour formation (AHF) (Larsson et al., 1995) or outflow facility (Krupin et al., 1977). Yet, other studies showed that NO donors has no effect on the IOP in rabbit (Taniguchi et al., 1998) or human (Kiss et al., 1999). Recently sodium azide (AZ), a nitrovasodilator, was shown to be able to lower the IOP in an isolated bovine eye by acting on the ciliary epithelial cells (CE) but not by relaxing the vascular smooth muscles (Millar et al., 1997; 2001). The significance of NO on AHF was further highlighted by the fact that L-NAME (L-nitro-L-arginine), a nitric oxide synthase (NOS) inhibitor, reduced the aqueous humour formation (AHF) in anaesthetised rabbit (Kiel et al., 2001). However, it was postulated that this reduction in the AHF was due to ciliary vasoconstriction, that is, blood-flow dependent. To complicate matter further, it was later reported that isosorbate-5-mononitrate, a NO donor, did not reduce AHF in healthy human volunteers (Kotikoski et al., 2003a). Since the AHF is an important determinant of IOP, we study the role of NO donors on the AH dynamics. Our hypothesis is that NO may directly regulate the AHF in addition to its effects on ocular vasculature and AH outflow. Indirect support to our hypothesis is now emerging. For instance, constitutive NOS (cNOS) activity has been detected in the bovine (Geyer et al., 1997) and porcine (Meyer et al., 1999) ciliary processes; basal nitric oxide production in the human and porcine ciliary processes has been shown to be inhibited by L-NAME (Haufschild et al., 2000); carbachol and NO can inhibit Na-K-ATPase activity of the bovine ciliary processes (Ellis et al., 2001) and stimulation of NO/cGMP pathway was shown to depolarise the epithelial transmembrane potential in porcine ciliary processes (Fleischhauer et al., 2000). In addition, NO has also been shown to be involved in fluid transport in other epithelia including kidney (Ortiz & Garvin, 2002) and salivary gland (Lomniczi et al., 1998). The aim of the present study was to investigate the effect of NO donors on the AHF and IOP in isolated arterially perfused pig eyes.

Axial elongation of the myopic eye has the potential to stretch the retina, thereby reducing the sampling density of retinal neurons. Resolution acuity in the peripheral field of normal eyes is known to be sampling-limited, which suggests that retinal stretching in the myopic eye should have a direct effect on resolution acuity everywhere in the visual field except perhaps the fovea, which is usually optically limited. We tested this prediction that neural sampling density is reduced in myopic eyes by measuring resolution acuity for sinusoidal gratings in the fovea plus five peripheral locations in 60 myopic subjects exhibiting a wide range of refractive errors. Control experiments using a detection paradigm to provoke spatial aliasing verified that peripheral resolution was sampling limited. Retinal spatial frequencies of the grating stimulus were computed assuming Knapps' Law of visual optics, which ensures that retinal image size (in mm) is independent of refractive error when axial myopia is corrected by a spectacle lens located in the anterior focal plane of the eye. Results obtained at every retinal locus showed that resolution acuity declined linearly with magnitude of refractive error. Regression of the population data indicated that approximately 15 D of refractive error doubles the spacing between retinal neurons, thereby halving peripheral resolution acuity relative to the emmetropic eye. Several subjects also demonstrated sampling-limited performance in the fovea, which indicated that optical filtering by the eye's optical system failed to protect the fovea from aliasing artifacts of neural undersampling in these eyes. We conclude that stretching of the retina is a primary cause of reduced spatial resolution of the peripheral field, and occasionally of the fovea, in myopic eyes. Stretching appears to be locally uniform over the central +/-15 degrees of visual field but is globally non-uniform since the foveal region appears to stretch more than the globe itself.

To investigate whether multifocal electroretinogram (mfERG) topography would be affected by nuclear cataract.Multifocal electroretinograms were recorded from 10 elderly subjects (10 eyes) with nuclear cataract of grade five (LOCS III) before and after cataract surgery (phacoemulsification). Their visual acuity before the cataract surgery was between 6/12 and 6/18. The postoperative period was from 2 to 3 months. None of the subjects had any significant eye disease apart from cataract. The mfERG responses were grouped into six concentric rings for analysis. Both the amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis.N1 amplitude only from ring 1 increased significantly after cataract surgery. P1 amplitude from ring 1 and ring 2 also increased significantly after cataract surgery. The latencies of neither N1 nor P1 from all rings changed significantly.Nuclear cataract could affect the topography of mfERG, so clinicians should be aware of the effects of cataract when interpreting mfERG responses in cataract patients.

To study the effect of aging retina on the multifocal electroretinogram (mfERG). A total of 18 young subjects (age 18–24 years) and 36 elderly subjects (aged 60–85 years) with intraocular lenses (IOLs) were recruited for this study. No subjects had significant eye diseases or media opacities. mfERG was measured in standard conditions using the VERIS system (version 4.1). There were three groups of 18 subjects: (1) 18–25 years, (2) 60-70 years, and (3) 75–85 years. mfERG responses were grouped into central, paracentral, and peripheral regions for analysis. The N1 amplitude, P1 amplitude, N1 latency, and P1 latency of the first-order responses were analysed. Age had no effect on P1 latency, N1 amplitude, and P1 amplitude; however, N1 latencies from central to peripheral regions were significantly longer for group 3 than for group 1. This study suggests that measured age-related decreases in mfERG responses are due to optical factors (decrease in retinal light levels, scatter) before the age of 70 years, but neural factors significantly affect mfERG topography after the age of 70 years.

Purpose: The purpose of this study was to determine the macular pigment optical density (MPOD) in a group of Chinese subjects using a simple customized light emitting diode-based device. Methods: Heterochromatic flicker photometry was used in this study. With a 1° diameter circular test stimulus, MPOD was estimated by comparing the relative sensitivities to a blue light, against a green reference, between foveal and parafoveal 4° temporal locations. Fixed alternating frequencies were used. Repeatability was determined on a small group of subjects. A further group of 67 young healthy subjects provided data for MPOD norms. Results: All results were corrected to the common MPOD reference wavelength of 460 nm. The group-averaged MPOD was 0.48 (S.D. 0.23). We found no gender difference in MPOD. The coefficient of variability was 7.2–8.0% and the coefficient of repeatability was 0.12. Conclusions: The MPOD of Chinese subjects did not differ greatly from the reported MPOD in white subjects.

The purpose of this study was to examine the development of the orbit in Hong Kong Chinese subjects. Orbit volume was determined from magnetic resonance images of 81 subjects aged from 1 to 42 years old. Results show that orbit volume ranged from 11.56 to 25.50 cm3. In the first year of life, the mean orbit volume was 12.36 cm3. The orbit showed rapid growth in the first 3 years of life. From about 1–3 years old, the mean volume was 15.31 cm3. The orbit grew steadily to the age of 10 years. From age 11 to 15 years old, the mean volume was 20.24 cm3. Orbit growth levelled off at about 16 years of age with the mean volume at 21.00 cm3.

Purpose. To study the effects of forward light scattering on the multifocal electroretinogram (mfERG). Methods. Thirty young normal subjects were recruited for this study. The mfERG was measured under five conditions. (1) no light scattering (stimulus contrast 93%), (2) mild light scattering (stimulus contrast 80%), (3) moderate light scattering (stimulus contrast 50%), (4) no light scattering (stimulus contrast 80%), and (5) no light scattering (stimulus contrast 50%). Results. The amplitudes of N1 and P1 from the central retina did not change significantly, but the amplitudes of N1 and P1 in the mid peripheral retina increased with the increase of forward light scattering. By comparing conditions 1, 4 and 5, it was shown that the amplitudes of N1 and P1 decreased at all eccentricities when stimulus contrast reduced from 93% to 50%. Conclusions. This study suggests that the topography and waveform of the mfERG could be affected by forward light scattering.

The purpose of this study is to determine if there is an association between eye size and the volume of the orbit in adult subjects. Thirty-three subjects with varying degrees of ametropia (+1.00 to -12.75 D) underwent magnetic resonance scan of the orbit. Results show that the larger myopic eye was not associated with a larger orbit.

All-trans-retinol dehydrogenase (RDH8) is a visual cycle enzyme that reduces all-trans-retinal to all-trans-retinol. As part of an on-going effort to map genes involved in complex eye diseases, myopia in particular, using association studies, single nucleotide polymorphisms (SNPs) were identified and linkage disequilibrium (LD) pattern was established within and around the RDH8 gene. We used denaturing high-performance liquid chromatography (DHPLC) to screen SNPs in four DNA pools each consisting of DNA from five individuals and genotyped the identified SNPs in 150 Chinese subjects from Hong Kong. Fifteen SNPs were identified: seven were common with the minor allele frequency >0.05 and ten were novel. Common SNPs were included in LD and haplotype analysis using the ASSOCIATE and EH programmes. Four SNPs in the 3' region exhibited significant LD and formed a haplotype block, while three common SNPs in the 5' region did not exhibit useful LD. The LD pattern around the RDH8 gene suggested that one SNP from the 3'region and two to three SNPs from the 5' region were needed in association studies involving RDH8. Our results demonstrated the efficiency of DHPLC in screening SNPs when coupled with DNA pooling strategy and in genotyping SNPs.

To identify genetic variants associated with refractive astigmatism in the general population, meta-analyses of genome-wide association studies were performed for: White Europeans aged at least 25 years (20 cohorts, N = 31,968); Asian subjects aged at least 25 years (7 cohorts, N = 9,295); White Europeans aged

Myopia can cause severe visual impairment. Here, we report a two-stage genome-wide association study for three myopia-related traits in 9,804 Japanese individuals, which was extended with trans-ethnic replication in 2,674 Chinese and 2,690 Caucasian individuals. We identify WNT7B as a novel susceptibility gene for axial length (rs10453441, Pmeta=3.9 × 10(-13)) and corneal curvature (Pmeta=2.9 × 10(-40)) and confirm the previously reported association between GJD2 and myopia. WNT7B significantly associates with extreme myopia in a case-control study with 1,478 Asian patients and 4,689 controls (odds ratio (OR)meta=1.13, Pmeta=0.011). We also find in a mouse model of myopia downregulation of WNT7B expression in the cornea and upregulation in the retina, suggesting its possible role in the development of myopia.

To compare and contrast the prevalence of myopia and other refractive errors in Xiamen city, Xiamen countryside (Southern China), and Singapore.One hundred thirty-two schoolchildren aged 6 to 7 years from Xiamen city, 104 from Xiamen countryside, and 146 from Singapore city were recruited to join the study. Cycloplegic autorefraction, keratometry, and biometry measurements were performed on all children.The prevalence of myopia was 12.3% in Singapore city, 9.1% in Xiamen city, and 3.9% in Xiamen countryside. The prevalence of astigmatism was higher in Singapore compared with Xiamen. The rates of hyperopia and anisometropia were similar in all three locations.The myopia rate in Singapore city was higher than in Xiamen city; the lowest rates were found in Xiamen countryside. As the Chinese population from all three sites is of similar genetic stock (predominantly from Southern China), it is postulated that the differences in myopia rates in these three localities may be related to environmental factors.

Author version made available in accordance with the publisher's policy., A mutation miR-184(+57C>T) in the seed region of miR-184 (encoded by MIR184 [MIM*613146]) results in familial severe keratoconus combined with early-onset anterior polar cataract and endothelial dystrophy, iris hypoplasia, congenital cataract, and stromal thinning (EDICT) syndrome (MIM#614303). In order to investigate the phenotypic spectrum resulting from MIR184 mutation, MIR184 was sequenced in a keratoconus cohort of mixed ethnicity and a Chinese axial myopia cohort. Sequencing of MIR184 was performed in 780 unrelated keratoconus patients and 96 unrelated Han southern Chinese subjects with axial myopia. Effects of identified mutations on RNA secondary structure were predicted computationally using mFold and RNAFold algorithms. MIR184 amplicons from patients harboring mutations were cloned and transfected into human embryonic kidney 293T (HEK293T) cells, and mature mutant miR-184 expression was analyzed by stem-loop real-time quantitative PCR (RT-qPCR). Two novel heterozygous substitution mutations in MIR184 were identified in the two patients with isolated keratoconus: miR-184(+8C>A) and miR-184(+3A>G). Computational modeling predicted that these mutations would alter the miR-184 stem-loop stability and secondary structure. Ex vivo miR-184 expression analysis demonstrated that miR-184(+8C>A) almost completely repressed the expression of miR-184 (P = 0.022), and miR-184(+3A>G) reduced the expression of miR-184 by approximately 40% (P = 0.002). There was no significant association of rs41280052, which lies within the stem-loop of miR-184, with keratoconus. No MIR184 mutations were detected in the axial myopia cohort. Two novel heterozygous substitution mutations in MIR184 were identified in two patients with isolated keratoconus: miR-184(+8C>A) and miR-184(+3A>G). Mutations in MIR184 are a rare cause of keratoconus and were found in 2 of 780 (0.25%) cases., Supported by Fight for Sight (United Kingdom; JL, CEW); The Research and Development Office, Northern Ireland (RRG Grant 4.46; CEW); Biotechnology and Biological Sciences Research Council, United Kingdom (Grant BB/H005498/1; JG-F, DAS); National Health and Medical Research Council of Australia (KPB, JEC); ALCON India (GG, MD, PS); and The Aravind Eye Care System (GG, MD, PS). JL is a Fight for Sight PhD student.

Professor Norhani Mohidin was born in a rubber plantation in Kampong Batang Benar in the State of Negeri Sembilan in Malaysia. The plantation was her grandfather's and there was enough land to gift...

Myopia is the most common ocular disease worldwide. We investigated the association of high myopia with the common single nucleotide polymorphisms (SNPs) of five candidate genes - early growth response 1 (EGR1), v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS), jun oncogene (JUN), vasoactive intestinal peptide (VIP), and vasoactive intestinal peptide receptor 2 (VIPR2). We recruited 1200 unrelated Chinese subjects with 600 cases (spherical equivalent ≤-8.00 diopters) and 600 controls (spherical equivalent within ±1.00 diopter). A discovery sample set was formed from 300 cases and 300 controls, and a replication sample set from the remaining samples. Tag SNPs were genotyped for the discovery sample set, and the most significant haplotypes and their constituent SNPs were followed up with the replication sample set. The allele and haplotype frequencies in cases and controls were compared by logistic regression adjusted for sex and age to give P a values, and multiple comparisons were corrected by permutation test to give P aemp values. Odd ratios (OR) were calculated accordingly. In the discovery phase, EGR1, JUN and VIP did not show any significant association while FOS and VIPR2 demonstrated significant haplotype association with high myopia. In the replication phase, the haplotype association for VIPR2 was successfully replicated, but not FOS. In analysis combining both sample sets, the most significant association signals of VIPR2 were the single marker rs2071625 (P a = 0.0008, P aemp = 0.0046 and OR = 0.75) and the 4-SNP haplotype window rs2071623-rs2071625-rs2730220-rs885863 (omnibus test, P a = 9.10e-10 and P aemp = 0.0001) with one protective haplotype (GGGG: P aemp = 0.0002 and OR = 0.52) and one high-risk haplotype (GAGA: P aemp = 0.0027 and OR = 4.68). This 4-SNP haplotype window was the most significant in all sample sets examined. This is the first study to suggest a role of VIPR2 in the genetic susceptibility to high myopia. EGR1, JUN, FOS and VIP are unlikely to be important in predisposing humans to high myopia.

Background The UMODL1 gene was found to be associated with high myopia in Japanese. This study aimed to investigate this gene for association with high myopia in Chinese. Methods Two groups of unrelated Han Chinese from Hong Kong were recruited using the same criteria: Sample Set 1 comprising 356 controls (spherical equivalent, SE, within ±1 diopter or D) and 356 cases (SE ≤ −8D), and Sample Set 2 comprising 394 controls and 526 cases. Fifty-nine tag single nucleotide polymorphisms (SNPs) were selected and genotyped for Sample Set 1. Four SNPs were followed up with Sample Set 2. Both single-marker and haplotype analyses were performed with cases defined by different SE thresholds. Secondary phenotypes were also analyzed for association with genotypes. Results Data filtering left 57 SNPs for analysis. Single-marker analysis did not reveal any significant differences between cases and controls in the initial study. However, haplotype GCT for markers rs220168-rs220170-rs11911271 showed marginal significance (empirical P = 0.076; SE ≤ −12D for cases), but could not be replicated in the follow-up study. In contrast, non-synonymous SNP rs3819142 was associated with high myopia (SE ≤ −10D) in the follow-up study, but could not be confirmed using Sample Set 1. The SNP rs2839471, positive in the original Japanese study, gave negative results in all our analyses. Exploratory analysis of secondary phenotypes indicated that allele C of rs220120 was associated with anterior chamber depth (adjusted P = 0.0460). Conclusions Common UMODL1 polymorphisms were unlikely to be important in the genetic susceptibility to high myopia in Han Chinese.

Purpose: To examine the symmetry of corneal changes following near work in the fellow eyes of non-amblyopic myopic anisometropes. Methods: Thirty-four non-amblyopic, myopic anisometropes (minimum 1 D spherical equivalent anisometropia) had corneal topography measured before and after a controlled near work task. Subjects were positioned in a headrest to minimise head movements and read continuous text on a computer monitor for 10 minutes at an angle of 25 degrees downward gaze and an accommodation demand of 2.5 D. Measures of the morphology of the palpebral aperture during primary and downward gaze were also obtained. Results: The more and less myopic eyes exhibited a high degree of interocular symmetry for measures of palpebral aperture morphology during both primary and downward gaze. Following the near work task, fellow eyes also displayed a symmetrical change in superior corneal topography (hyperopic defocus) which correlated with the position of the upper eyelid during downward gaze. Greater changes in the spherical corneal power vector (M) following reading were associated with narrower palpebral aperture during downward gaze (p = 0.07 for more myopic and p = 0.03 for less myopic eyes). A significantly greater change in J0 (an increase in against the rule astigmatism) was observed in the more myopic eyes (-0.04 ± 0.04 D) compared to the less myopic eyes (-0.02 ± 0.06 D) over a 6 mm corneal diameter (p = 0.01). Conclusions: Changes in corneal topography following near work are highly symmetrical between the fellow eyes of myopic anisometropes due to the interocular symmetry of the palpebral aperture. However, the more myopic eye exhibits changes in corneal astigmatism of greater magnitude compared to the less myopic eye.

Tear volume, measured using a cotton thread test (CTT), was assessed in 91 Hong Kong (HK)-Chinese (46 females,45 males aged from 8 to 70 years) and 35 Singapore (S)-Chinese (21 females, 14 males aged from 7 to 65 years). The mean (±SD) CTT value of HK-Chinese and S-Chinese was 17.5 (±8.1) mm/min and 19.6 (±12.0) mm/min respectively. No significant difference in the CTT values between the two groups of Chinese was found, so their data were pooled. The mean (±SD) CTT value of the pooled data was 18.1 (±9.3) mm/min; 18.4 (±9.0) mm/min for female subjects and 17.8 (±9.7) mm/min for male subjects. Regression statistics of the pooled CTT values on age showed a correlation of −0.59 (p

We surveyed and assessed 2,323 schoolchildren aged seven to 17 years from four schools in China, two in the city of Tianjin and the other two in a neighbouring rural village, Ban Chau, to investigate the prevalence of refractive error and its relationship with environmental factors. Every child from each of the participating classes was recruited in this study to avoid self-selection. A questionnaire was issued which queried some aspects of the child's visual habits and home. Refraction was canied out using the Canon R-22 autorefractor. The degree and frequency of myopia in these children increased almost linearly from age seven to 17 years. There was little difference between the urban and rural groups. Of the factors explored, the number of hours spent on near work showed the best correlation with the degree of myopia, albeit only weakly.

Background: The aim was to examine the progression and regression of diabetic retinopathy within a four-year period in a Chinese population with type 2 diabetes mellitus in a community optometry clinic in Hong Kong. Methods: During the period May 2005 to November 2009, 5,160 patients with type 2 diabetes mellitus who had attended at least two diabetic retinopathy screening sessions at a community optometry clinic were included as subjects in this study. All had retinal photographs taken of both eyes, which were of sufficiently good quality for grading. For the purpose of this study, diabetic retinopathy grading was based on the results of the worst eye. The main outcomes were the within four-year incidence of diabetic retinopathy and the incidence of progression and regression of diabetic retinopathy. Results: Of the 5,160 subjects in this study, 3,647 had no diabetic retinopathy, while 1,513 had diabetic retinopathy at the baseline visit. Of those 3,647 subjects with no diabetic retinopathy, the within four-year cumulative incidence of any diabetic retinopathy, mild or moderate non-proliferative diabetic retinopathy and sight-threatening diabetic retinopathy was 15.16 per cent, 14.45 per cent, 0.69 per cent and 0.03 per cent, respectively. Of those 1,513 subjects with diabetic retinopathy at baseline, the within four-year progression incidence of diabetic retinopathy was 6.61 per cent and the regression incidence of diabetic retinopathy was 45.54 per cent. Conclusion: The high regression incidence of diabetic retinopathy suggests that it might not be necessary for all patients with diabetes to be screened annually. Other methods to determine the screening frequency for an individual patient should be explored.

PURPOSE. To investigate the relationship between high myopia and single nucleotide polymorphisms (SNPs) in six proteoglycan genes: aggrecan (ACAN), fibromodulin (FMOD), decorin (DCN), lumican (LUM), keratocan (KERA), and epiphycan (EPYC). These genes were selected for study because they are involved in induced myopia in animals and/or are within the human MYP3 locus identified by linkage analysis of families with high myopia. METHODS. Two groups of Chinese subjects were studied: group 1 (300 cases and 300 controls) and group 2 (356 cases and 354 controls). Cases were high myopes with spherical equivalent (SE) ≤ -8.00 D, and controls had SE between +1.0 and -1.0 D. From these candidate genes, 60 tagging SNPs were selected. First, 12 DNA pools were each constructed from 50 samples of the same phenotype from group 1 subjects and were tested for association with the SNPs. Second, putatively positive SNPs were confirmed by individual genotyping of group 1 subjects. Finally, positive results were replicated in group 2 subjects. RESULTS. Of the 58 SNPs successfully screened by DNA pooling, 8 ACAN SNPs passed the threshold of P ≤ 0.10 (nested ANOVA) and were then genotyped in the individual samples. Haplotypes rs3784757 and rs1516794 showed significant association with high myopia. However, the positive result could not be replicated in the second subject group. CONCLUSIONS. These six proteoglycan genes were not associated with high myopia in these Chinese subjects and hence are unlikely to be important in the genetic predisposition to high myopia.