Compression forces of haptics of freely rotating posterior chamber intraocular lenses.

Abstract Purpose: To measure the compressive forces of the haptics of 28 intraocular lens (IOL) models for different modes of compression and compare the results of two types of measurements. Setting: Department of Ophthalmology, Central Hospital of Central Finland, Jyvaskyla, Finland. Methods: The haptics of 28 types of IOLs were compressed to a diameter of 9.0 mm between curved anvils. The compression forces in the plane of compression (i.e., in the plane of the optics) were measured at 0.5 mm intervals. During compression, the optics and the haptics were free to rotate with respect to the anvils. The results were compared with those of earlier measurements in which the optics were held f…

What is the influence of parents' myopia on their children's myopic progression? A 22-year follow-up study.

Purpose To study the connection between parental myopia and their children's myopia from school age to adulthood. Methods Two hundred and forty myopic schoolchildren (119 boys, 121 girls, mean age 10.9 years) with no previous spectacles for myopia were recruited to a 3-year treatment trial with different use of spectacles. Follow-ups were performed at mean ages of 13.9, 23.7 and 33.2 years for 238, 176 and 170 subjects respectively. Subjective refraction was calibrated to the spherical equivalent at corneal level (SEcor). Corneal refractive power (CR) and axial length (AL) were measured. Parental myopia was assessed with a questionnaire and the children assigned accordingly to one of three …

IMI Prevention of Myopia and Its Progression

The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy…

Anisometropia of spherical equivalent and astigmatism among myopes: a 23-year follow-up study of prevalence and changes from childhood to adulthood.

Purpose To study anisometropia of spherical equivalent and astigmatism from the onset of myopia at school age to adulthood. Methods A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Examinations with subjective cyclopedic refraction were repeated 3 years later (follow-up 1) for 238 subjects and thereafter at the mean ages of 23.2 (follow-up 2) and 33.9 years (follow-up 3) for 178 and 134 subjects. After exclusions, the 102 subjects who attended all three follow-ups were included in the analyses. Corneal refractive power and astigmatism and anterior cha…

Associations of Children’s Close Reading Distance and Time Spent Indoors with Myopia, Based on Parental Questionnaire

Purpose: To study the association of parents’ reports about their children’s near work and outdoor habits with myopia in their children. Methods: Data from a questionnaire study conducted in 1983 among Finnish schoolchildren were reanalyzed. Vision screening had been performed for all the schoolchildren (n = 4961) in the 1st, 5th, and 8th grades (7-, 11-, and 15-year-olds) in an area of Central Finland. The questionnaire, including information about myopia, was returned by 4305 (86.7%) participants. Items concerned parents’ estimates of their child’s habitual reading distance, time spent indoors as compared with age peers, daily near work, outdoors time, and parents&…

Retinal light sensitivity of the central visual field among 70- to 81-year-old men and women.

Retinal light sensitivity of the central visual field (0-30 degrees), visual acuity, intraocular pressure and pupillary size were screened in 42 men and 42 women aged 70 to 81 years. The subjects were randomly selected from the population register. After excluding the diagnosed glaucoma cases, the men had better visual field light sensitivity values than the women. They also had lower intraocular pressure and a wider pupillary diameter than the women, whereas there were no differences in visual acuity between the sexes. When the effect of pupillary size was controlled the differences in visual field light sensitivity values between men and women became non-significant. Among these elderly p…

Genome-wide meta-analyses of multiancestry cohorts identify multiple new susceptibility loci for refractive error and myopia

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Heritability of Intraocular Pressure in Older Female Twins

Purpose To examine the heritability of intraocular pressure (IOP) among older women not diagnosed as having glaucoma. Design Cross-sectional twin study. Participants 94 monozygotic (MZ) and 96 dizygotic (DZ) female twin pairs aged 63–76 years and not diagnosed as having glaucoma. Methods Intraocular pressure was measured using a noncontact tonometer. The contributions of genetic and environmental factors to individual differences in IOP were estimated by applying an independent pathway model to twin data. Main Outcome Measures Contribution of genetic and environmental effects to the variation in IOP among MZ and DZ twins. Results Mean IOP of the study population was 14.1 mmHg (± standard de…

Heritability of refractive astigmatism: a population-based twin study among 63- to 75-year-old female twins.

PURPOSE: To examine the heritability of refractive astigmatism in older women. METHODS: Astigmatism was measured with an autorefractor in 88 monozygotic and 82 dizygotic female twin pairs aged 63 to 75 years. The prevalence and distribution of astigmatism and polar values J0 and J45 were estimated by standard statistical methods. Bivariate maximum likelihood model fitting was used to estimate genetic and environmental variance components using information from both eyes. RESULTS: Mean astigmatism of the more astigmatic eye was 0.93 diopters (D; SD ±0.58). Astigmatism of at least 0.25 D, 0.5 D, 0.75 D, or 1.0 D in either eye was present in 99.7%, 88.5%, 66.5%, and 46.2% of cases, respectivel…

Nine Loci for Ocular Axial Length Identified through Genome-wide Association Studies, Including Shared Loci with Refractive Error

Refractive errors are common eye disorders of public health importance worldwide. Ocular axial length (AL) is the major determinant of refraction and thus of myopia and hyperopia. We conducted a meta-analysis of genome-wide association studies for AL, combining 12,531 Europeans and 8,216 Asians. We identified eight genome-wide significant loci for AL (RSPO1, C3orf26, LAMA2, GJD2, ZNRF3, CD55, MIP, and ALPPL2) and confirmed one previously reported AL locus (ZC3H11B). Of the nine loci, five (LAMA2, GJD2, CD55, ALPPL2, and ZC3H11B) were associated with refraction in 18 independent cohorts (n = 23,591). Differential gene expression was observed for these loci in minus-lens-induced myopia mouse …

Myopia, use of eyes, and living habits among men aged 33-37 years

As a part of a more extensive research project on health and functional capacity among a representative sample of men, the living habits and backgrounds of myopic men between 33 and 37 years of age living in the town of Jyväskylä were studied in comparison with non-myopic men of the same age. The prevalence of a negative spheric equivalent, which was considered as a criterion of myopia, was 25%. It was found that the myopic, on the average, had been more interested in reading from childhood onwards, their educational and occupational status were higher, and their body structure was lighter. As children they had taken less physical exercise, but as adults no difference was found in physical …

Heritability of anterior chamber depth and axial length: a population-based twin study among 66 to 79-year old female twins.

Meta-analysis of gene-environment-wide association scans accounting for education level identifies additional loci for refractive error

Myopia is the most common human eye disorder and it results from complex genetic and environmental causes. The rapidly increasing prevalence of myopia poses a major public health challenge. Here, the CREAM consortium performs a joint meta-analysis to test single-nucleotide polymorphism (SNP) main effects and SNP × education interaction effects on refractive error in 40,036 adults from 25 studies of European ancestry and 10,315 adults from 9 studies of Asian ancestry. In European ancestry individuals, we identify six novel loci (FAM150B-ACP1, LINC00340, FBN1, DIS3L-MAP2K1, ARID2-SNAT1 and SLC14A2) associated with refractive error. In Asian populations, three genome-wide significant loci AREG…

Heritability of Spherical Equivalent

Purpose To examine the heritability of spherical equivalent (SE) in older women. Design Population-based twin study. Participants Ninety monozygotic (MZ) and 86 dizygotic (DZ) female twin pairs aged 63 to 76 years who were born from 1924 through 1937. Methods Ocular refraction was measured using an autorefractor and controlled by the subjective method. The contributions of genetic and environmental factors to individual differences in SE were estimated by applying an independent pathway model to twin data. Main Outcome Measures Contribution of genetic and environmental effects to the variation in SE. Results Mean SE of the study population was 1.68 (standard deviation, ±1.82) with no differ…

Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error

Corneal curvature, a highly heritable trait, is a key clinical endophenotype for myopia - a major cause of visual impairment and blindness in the world. Here we present a trans-ethnic meta-analysis of corneal curvature GWAS in 44,042 individuals of Caucasian and Asian with replication in 88,218 UK Biobank data. We identified 47 loci (of which 26 are novel), with population-specific signals as well as shared signals across ethnicities. Some identified variants showed precise scaling in corneal curvature and eye elongation (i.e. axial length) to maintain eyes in emmetropia (i.e. HDAC11/FBLN2 rs2630445, RBP3 rs11204213); others exhibited association with myopia with little pleiotropic effects …

Genetic Variants Associated With Human Eye Size Are Distinct From Those Conferring Susceptibility to Myopia

Purpose: Emmetropization requires coordinated scaling of the major ocular components, corneal curvature and axial length. This coordination is achieved in part through a shared set of genetic variants that regulate eye size. Poorly coordinated scaling of corneal curvature and axial length results in refractive error. We tested the hypothesis that genetic variants regulating eye size in emmetropic eyes are distinct from those conferring susceptibility to refractive error. Methods: A genome-wide association study (GWAS) for corneal curvature in 22,180 adult emmetropic individuals was performed as a proxy for a GWAS for eye size. A polygenic score created using lead GWAS variants was tested fo…

Childhood gene-environment interactions and age-dependent effects of genetic variants associated with refractive error and myopia: The CREAM Consortium.

Myopia, currently at epidemic levels in East Asia, is a leading cause of untreatable visual impairment. Genome-wide association studies (GWAS) in adults have identified 39 loci associated with refractive error and myopia. Here, the age-of-onset of association between genetic variants at these 39 loci and refractive error was investigated in 5200 children assessed longitudinally across ages 7-15 years, along with gene-environment interactions involving the major environmental risk-factors, nearwork and time outdoors. Specific variants could be categorized as showing evidence of: (a) early-onset effects remaining stable through childhood, (b) early-onset effects that progressed further with i…

Large scale international replication and meta-analysis study confirms association of the 15q14 locus with myopia. The CREAM consortium.

Myopia is a complex genetic disorder and a common cause of visual impairment among working age adults. Genome-wide association studies have identified susceptibility loci on chromosomes 15q14 and 15q25 in Caucasian populations of European ancestry. Here, we present a confirmation and meta-analysis study in which we assessed whether these two loci are also associated with myopia in other populations. The study population comprised 31 cohorts from the Consortium of Refractive Error and Myopia (CREAM) representing 4 different continents with 55,177 individuals; 42,845 Caucasians and 12,332 Asians. We performed a meta-analysis of 14 single nucleotide polymorphisms (SNPs) on 15q14 and 5 SNPs on …

Sensitivity of the central visual field in 70- to 81-year-old male athletes and in a population sample.

The sensitivity of the central visual field (0°–30°) was studied using an automatic Octopus 500E perimeter in elderly male athletes and in a population sample of men of corresponding age. The athletes (N=96) were endurance and power athletes, who were still active in competitive sports with training histories spanning tens of years. The athletes’ results were compared with those of a sample of men of the same age (70–81 years, N=41) randomly selected from the local population register. The sensitivity values of the athletes, and the endurance athletes in particular, were significantly better than those of the controls, with differences varying from 1 to 2.5 dB in the different areas of the …

Astigmatism among myopics and its changes from childhood to adult age: a 23‐year follow‐up study

Purpose To study the prevalence of and changes in astigmatism from the onset of myopia at school age. Methods Two hundred and forty myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Three annual examinations with subjective cycloplegic refraction were performed for 237–238 subjects. Subsequent examinations were performed at the mean ages of 23.2 and 33.9 years for 178 and 163 subjects, and the last examination, including data from prescriptions of different ophthalmologists, for 32 subjects. Corneal topography was studied at baseline, at the 3-year follow-up and at t…

Heritability of corneal refraction and corneal astigmatism: a population-based twin study among 66- to 79-year-old female twins.

. Purpose:  To examine the heritability of corneal refraction power (CR) and corneal astigmatism (AST) in older women. Methods:  Corneal refraction and AST were measured by IOL master in 52 monozygotic (MZ) and 47 dizygotic (DZ) female twin pairs aged 66–79 years. The relative contribution of genetic and environmental factors to individual differences in CR was estimated by applying an independent pathway model to the twin data and AST by intraclass correlations (ICC). Results:  For the right eye, mean CR was 44.58 dioptres (D) (standard deviation (SD) ±1.28) When comparing CR of the right and left eye between MZ and DZ, no significant difference was found. Mean AST was 0.77 D (SD ±0.44) wi…

Effect of bicycle ergometer test on intraocular pressure in elderly athletes and controls.

To evaluate the effect of intensive physical exercise on intraocular pressure (IOP) in 66- to 85-year-old subjects IOP was measured before and after a maximal bicycle ergometer test. The non-glaucomatous subjects comprised 85 males and 36 female athletes and 16 male and 22 female controls of corresponding age drawn from a population register. IOP was measured using a non-contact tonometer. The results indicated a decrease (> or = 2 mmHg) in 34% of the subjects, no change in 57% and an increase in 9%. The decrease was more pronounced in subjects with higher pre-test values. In all four subjects with a pre-test value above 22 mmHg a reduction from 4 to 11 mmHg was observed. The change in IOP …

Genome-wide meta-analyses of multiancestry cohorts identify multiple new susceptibility loci for refractive error and myopia

Refractive error is the most common eye disorder worldwide and is a prominent cause of blindness. Myopia affects over 30% of Western populations and up to 80% of Asians. The CREAM consortium conducted genome-wide meta-analyses, including 37,382 individuals from 27 studies of European ancestry and 8,376 from 5 Asian cohorts. We identified 16 new loci for refractive error in individuals of European ancestry, of which 8 were shared with Asians. Combined analysis identified 8 additional associated loci. The new loci include candidate genes with functions in neurotransmission (GRIA4), ion transport (KCNQ5), retinoic acid metabolism (RDH5), extracellular matrix remodeling (LAMA2 and BMP2) and eye…

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, t…

Intraocular pressure in samples of elderly Finnish and Swedish men and women.

Abstract Intraocular pressure was measured in 231 systematically sampled 75-year-old men and women in Goteborg, Sweden and in 284 75-year-old and 201 80-year-old residents in Jyvaskyla, Finland as part of a comparative study on functional capacity and health, NORA 75 (Nordic Research on Ageing). After excluding the cases reporting glaucoma in their medical history or using drugs for glaucoma treatment there were no significant differences in the distributions of intraocular pressure between the men (mean intraocular pressure in the right eye 15.1 mmHg, left eye 15.0 mmHg) and women (mean intraocular pressure in the right eye 15.5 mmHg, left eye 15.8 mmHg) in Goteborg. In Jyvaskyla the 75-ye…

Genome-wide association study for refractive astigmatism reveals genetic co-determination with spherical equivalent refractive error: the CREAM consortium

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 <25 years (4 cohorts, N = 5,640); and all independent individuals from the above three samples combined with a sample of Chinese subjects aged <25 years (N = 45,931). Participants were classified as cases with refractive astigmatism if the average cylinder power in their two eyes was at least 1.00 diopter and as controls otherwise. Genome-wide association analysis was carried out for …

Lowered vision as a risk factor for injurious accidents in older people

Poor vision in older people is often related to increased fall risk. However, the association of the severity between visual deficit and risk for all kind of injurious accidents has not been widely studied. The aim of this study was to examine whether visual loss is associated with higher incidence of injurious accidents and whether walking speed or physical activity play a mediating role in the association.416 persons aged 75 and 80 years at baseline underwent visual acuity measurements. Visual acuity (VA)0.3 in the better eye, with spectacle correction when necessary, was defined as visual impairment, VAor=0.3 butor=0.5 as lowered vision, and VA0.5 as normal VA. Hospital records of accide…

Commonly occurring genetic polymorphisms with a major impact on the risk of nonsyndromic strabismus: replication in a sample from Finland

PURPOSE To replicate associations between polymorphisms in the WRB and TSPAN10 genes and strabismus in an independent Finnish cohort and to calculate their population attributable risk. METHODS Polymorphisms in the WRB (rs2244352) and TSPAN10 (rs6420484) genes were investigated in individuals from the FinnGen study group who had one of three categories of strabismus, with clinical diagnoses of (1) "strabismus-all subtypes" (3,515 cases and 173,384 controls), (2) "convergent concomitant strabismus" (ICD-10 code H50.0; 737 cases and 170,976 controls), and (3) "divergent concomitant strabismus" (ICD-10 code H50.1; 1,059 cases and 170,976 controls). RESULTS The WRB polymorphism was associated w…

Heredity of interocular similarities in components of refraction: a population-based twin study among 66- to 79-year-old female twins.

Purpose: To examine genetic influences on interocular similarities in ocular refraction and components of refraction among elderly female twins. Methods: Refraction was assessed in 94 monozygotic (MZ) and 74 dizygotic (DZ) female twins aged 66–78 years. Absolute values of interocular differences (Aniso variables) in spherical refraction (SR), refractive astigmatism (AST), spherical equivalent (SE), corneal refractive power (CR), corneal astigmatism (CAST), anterior chamber depth (ACD) and axial length (AL) were calculated. The differences between sisters in each of the Aniso variables were calculated and graded into two categories, best differentiating the groups, here isometropic and aniso…

Anisometropia of ocular refractive and biometric measures among 66- to 79-year-old female twins

Purpose To examine the prevalence of anisometropia of spherical refraction (AnisoSR), astigmatism (AnisoAST) and spherical equivalent (AnisoSE) and their associations with spherical refraction (SR), refractive astigmatism (AST), spherical equivalent (SE) and interocular differences of ocular biometric parameters among elderly female twins. Methods Refraction of 117 monozygotic (MZ) and 116 dizygotic (DZ) female twin subjects aged 66–79 years was assessed with an auto-refractor (Topcon AT) and controlled by subjective refraction. Corneal refraction, anterior chamber depth and axial length were measured with a Zeiss IOL Master. Participants with eyes operated for cataract or glaucoma were exc…

Associations of near work time, watching TV, outdoors time, and parents' myopia with myopia among school children based on 38-year-old historical data.

Purpose To study the prevalence and risk factors of myopia with data from a questionnaire study conducted in 1983 among Finnish school children. Methods School children (n = 4 961) from the 1st, 5th and 8th grades of school (7-, 11- and 15-year-olds) in Central Finland were screened for vision followed by a questionnaire, which was returned by 4 352 (87.7%) participants. Myopia was categorized based on the questionnaire. Items concerned daily time spent on near work and outdoor activities, excluding time spent at school, watching TV and parental myopia and the associations of myopia with these factors were studied. Results The prevalence of myopia was 3%, 15% and 27% among the 7-, 11- and 1…

Compression forces of haptics of selected posterior chamber lenses

Abstract Purpose: To compare the compressive forces of the haptics of different intraocular lens (IOL) models and analyze the observed differences. Setting: Central Hospital of Central Finland and University of Jyvaskyla, Jyvaskyla, Finland. Methods: The haptics of 28 IOL models were compressed to a diameter of 9.0 mm. The compression forces were measured at 0.5 mm intervals. The conclusions were verified by numerical simulations of mechanical models of the lenses. Results: The measured forces varied between 100 and 601 mg at a diameter of 11.0 mm, 206 and 1057 mg at a diameter of 10.0 mm, and 315 and 2094 mg at a diameter of 9.0 mm. The slopes of the force curves of the three-piece lenses …

Comparison of myopic progression in Finnish and Singaporean children

Purpose To compare 3-year myopic progression between Finnish and Singaporean children. Methods Myopic progression was compared between 9-year-old (mean age 9.7 ± 0.4 years, n = 92) and 11-year-old (mean age 11.7 ± 0.4 years, n = 144) Finnish (Finnish RCT) children and Singaporean children matched by age and refraction (SCORMMatched, n = 403) and 7- to 8-year-old Singaporean children matched only by refraction (SCORM Young, n = 186). Spherical equivalent (SE) was between −0.50 and −3.00 D. Refraction with cycloplegia was controlled annually for 3 years. Information on parental myopia, mother’s education, time spent on near-work and outdoor time was gathered by parental questionnaire. Results…

Visual Acuity and Mortality in Older People and Factors on the Pathway

To examine vision as a predictor of mortality in older people and the role of mobility, depressed mood, chronic diseases, body mass index, physical activity and injurious accidents in this possible association.223 persons aged 75 and 193 persons aged 80 years at the baseline participated in visual acuity measurements. Visual acuity (VA) of0.3 in the better eye was defined as visual impairment, VA ofor = 0.3 butor = 0.5 as lowered vision and VA0.5 as normal VA. Death dates were received from the official register. Cox regression models were used to determine the relative risks of mortality and to study what factors lie on the pathway from poor vision to mortality.Over the 10-year follow-up, …

Rare variant analyses across multiethnic cohorts identify novel genes for refractive error

Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopi…

The progression of myopia from its onset at age 8-12 to adulthood and the influence of heredity and external factors on myopic progression. A 23-year follow-up study

Purpose To examine myopic progression and factors connected with myopic progression. Methods Myopic schoolchildren, with no previous spectacles, 119 boys and 121 girls, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia with a subsequent 20-year follow-up. Participants' mean age at Baseline was 10.9, ranging from 8.7 to 12.8 years. An ophthalmological examination was carried out annually for 3 years and twice thereafter at ca. 10-year intervals. Additional refraction values were received from prescriptions issued by different ophthalmologists and opticians. Altogether, 1915 refraction values were available. Reading distance and accommodation…

Risk factors for high myopia: a 22‐year follow‐up study from childhood to adulthood

PURPOSE To determine the effect of the definition of high myopia on its prevalence and risk factors for high myopia. METHODS A total of 240 myopic schoolchildren (119 boys and 121 girls) at the mean age of 10.9 years (range 8.8-12.8 years) were recruited to a randomized clinical trial of myopia treatment among children from 3rd- and 5th grades of school referred for an eye examination due to poor distant vision and having no previous spectacles. Clinical follow-ups, including refraction with cycloplegia, were conducted annually at 3 years [third follow-up here = clinical follow-up 1, (n = 237)], and thereafter twice at approximately 10-year intervals [clinical follow-ups 2 (n = 179) and 3, …

Poor vision accompanied with other sensory impairments as a predictor of falls in older women

Objectives:we studied visual acuity (VA) and co-existing hearing impairment and poor standing balance as predictors of falls. Design: prospective study with 1-year follow-up. Setting: research laboratory and residential environment. Participants: 428 women aged 63‐76 years from the Finnish Twin Study on Aging. Measurements: participants were followed up for incidence of falls over 1 year. VA, hearing ability and standing balance were assessed at the baseline. The incidence rate ratios (IRR) for falls were computed using the negative binomial regression model. Results: during the follow-up, 47% of participants experienced a fall. After adjusting for age and interdependence of twin sisters, p…

Genetic variants associated with human eye size are distinct from those conferring susceptibility to myopia

Purpose: Emmetropization requires coordinated scaling of the major ocular components, corneal curvature and axial length. This coordination is achieved in part through a shared set of genetic variants that regulate eye size. Poorly coordinated scaling of corneal curvature and axial length results in refractive error. We tested the hypothesis that genetic variants regulating eye size in emmetropic eyes are distinct from those conferring susceptibility to refractive error.Methods: A genome-wide association study (GWAS) for corneal curvature in 22,180 adult emmetropic individuals was performed as a proxy for a GWAS for eye size. A polygenic score created using lead GWAS variants was tested for…

Evaluation of Shared Genetic Susceptibility to High and Low Myopia and Hyperopia

Importance: Uncertainty currently exists about whether the same genetic variants are associated with susceptibility to low myopia (LM) and high myopia (HM) and to myopia and hyperopia. Addressing this question is fundamental to understanding the genetics of refractive error and has clinical relevance for genotype-based prediction of children at risk for HM and for identification of new therapeutic targets. Objective: To assess whether a common set of genetic variants are associated with susceptibility to HM, LM, and hyperopia. Design, Setting, and Participants: This genetic association study assessed unrelated UK Biobank participants 40 to 69 years of age of European and Asian ancestry. Par…

Associations of reading posture, gaze angle and reading distance with myopia and myopic progression

Purpose To study the associations of habitual reading posture, gaze angle in reading and reading distance with myopia and changes in myopia among myopic children. Methods A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983–1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Three annual examinations with subjective cycloplegic refraction were conducted for 237–238 subjects. A further examination was conducted at the mean age of 23.2 years for 178 subjects. Habitual reading posture was elicited by questionnaire at study outset. Reading distance was measured with a Clement Clark accommodometer and gaze angl…

Myopia - maailmanlaajuinen epidemia

• Myopian eli likinäköisyyden esiintyvyys on viime vuosikymmeninä lisääntynyt voimakkaasti. • Tähän ovat ilmeisesti vaikuttaneet voimakkaimmin lähikatselun lisääntyminen ja ulkona vietetyn ajan väheneminen. Perintötekijät selittävät myopiasta vain pienen osan. • Ulkoilun lisäämisellä ja pitkäkestoisen lähikatselun välttämisellä on voitu vähentää lasten myopian ­ilmaantuvuutta. • Useiden silmäsairauksien ja näkövammaisuuden riski lisääntyy myopian voimistuessa. • Atropiinisilmätippojen käytöstä on raportoitu olevan hyötyä likinäköisyyden etenemisen hidastamisessa, mutta pidempiaikaisista hyödyistä ja mahdollisista haitoista tarvitaan seurantatietoa. The prevalence of myopia has increased sig…