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Clinical & Experimental Optometry Jan 2020Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result... (Review)
Review
Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual-focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.
Topics: Accommodation, Ocular; Astigmatism; Contact Lenses, Hydrophilic; Corneal Wavefront Aberration; Eye; Eyeglasses; Humans; Myopia; Orthokeratologic Procedures; Refractive Errors
PubMed: 31489693
DOI: 10.1111/cxo.12960 -
Clinical & Experimental Optometry Nov 2011This paper discusses the considerations for prescribing a refractive correction in infants and children up to and including school age, with reference to the current... (Review)
Review
This paper discusses the considerations for prescribing a refractive correction in infants and children up to and including school age, with reference to the current literature. The focus is on children who do not have other disorders, for example, binocular vision anomalies, such as strabismus, significant heterophoria or convergence excess. However, refractive amblyogenic factors are discussed, as is prescribing for refractive amblyopia. Based on this discussion, guidelines are proposed, which indicate when to prescribe spectacles and what amount of refractive error should be corrected. It may be argued that these are premature because there are many questions that remain unanswered and we do not have the quality of evidence that we would like; the clinician, however, must make decisions on whether and what to prescribe when examining a child. These guidelines are to aid clinicians in their current clinical decision making.
Topics: Child; Child, Preschool; Decision Making; Eyeglasses; Humans; Infant; Practice Guidelines as Topic; Prescriptions; Refractive Errors
PubMed: 21722183
DOI: 10.1111/j.1444-0938.2011.00600.x -
Frontiers in Public Health 2022Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15-16 years old. Thus, most studies on myopia have... (Review)
Review
Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15-16 years old. Thus, most studies on myopia have centered on children. Data on the refractive error profile in young adulthood - a time in life when myopia is thought to have stabilized and refractive error is unaffected by age-related pathology such as cataract - are limited. The Raine Study has been following a community-based cohort of young adults representative of the general Western Australia population since their prenatal periods in 1989-1991, with eye examinations performed when participants were 20 and 28 years old. At 20 years old, prevalence of myopia in the cohort was 25.8%. Using long-term trajectory of serum vitamin D levels and conjunctival ultraviolet autofluorescence (CUVAF) area to objectively quantify sun exposure, the Raine Study confirmed a negative relationship between time spent outdoors and myopia prevalence. However, prospective studies are required to determine the amount of CUVAF area or serum vitamin D levels associated with time duration. Combining data from the Raine Study and several other cohorts, Mendelian randomization studies have confirmed a link between myopia and a genetic predisposition toward higher education. Several novel potential associations of myopia or ocular biometry were investigated, including fetal growth trajectory, which was found to be significantly associated with corneal curvature at 20 years. By age 28, myopia prevalence had increased to 33.2%. Between 20 and 28 years old, myopia progressed and axial length elongated, on average, by -0.041D/year and 0.02 mm/year, respectively. Smaller CUVAF area at follow-up, female sex, and parental myopia were significant risk factors for myopia incidence and progression between 20 and 28 years. Given the limited research in young adults, further investigations are warranted to confirm the Raine Study findings, as well as identify novel genetic or environmental factors of myopia incidence and progression in this age group.
Topics: Adolescent; Adult; Child; Conjunctiva; Female; Humans; Myopia; Pregnancy; Prevalence; Refractive Errors; Risk Factors; Vitamin D; Young Adult
PubMed: 35570945
DOI: 10.3389/fpubh.2022.861044 -
BMJ (Clinical Research Ed.) Jun 2018To determine whether more years spent in education is a causal risk factor for myopia, or whether myopia is a causal risk factor for more years in education.
OBJECTIVES
To determine whether more years spent in education is a causal risk factor for myopia, or whether myopia is a causal risk factor for more years in education.
DESIGN
Bidirectional, two sample mendelian randomisation study.
SETTING
Publically available genetic data from two consortiums applied to a large, independent population cohort. Genetic variants used as proxies for myopia and years of education were derived from two large genome wide association studies: 23andMe and Social Science Genetic Association Consortium (SSGAC), respectively.
PARTICIPANTS
67 798 men and women from England, Scotland, and Wales in the UK Biobank cohort with available information for years of completed education and refractive error.
MAIN OUTCOME MEASURES
Mendelian randomisation analyses were performed in two directions: the first exposure was the genetic predisposition to myopia, measured with 44 genetic variants strongly associated with myopia in 23andMe, and the outcome was years in education; and the second exposure was the genetic predisposition to higher levels of education, measured with 69 genetic variants from SSGAC, and the outcome was refractive error.
RESULTS
Conventional regression analyses of the observational data suggested that every additional year of education was associated with a more myopic refractive error of -0.18 dioptres/y (95% confidence interval -0.19 to -0.17; P<2e-16). Mendelian randomisation analyses suggested the true causal effect was even stronger: -0.27 dioptres/y (-0.37 to -0.17; P=4e-8). By contrast, there was little evidence to suggest myopia affected education (years in education per dioptre of refractive error -0.008 y/dioptre, 95% confidence interval -0.041 to 0.025, P=0.6). Thus, the cumulative effect of more years in education on refractive error means that a university graduate from the United Kingdom with 17 years of education would, on average, be at least -1 dioptre more myopic than someone who left school at age 16 (with 12 years of education). Myopia of this magnitude would be sufficient to necessitate the use of glasses for driving. Sensitivity analyses showed minimal evidence for genetic confounding that could have biased the causal effect estimates.
CONCLUSIONS
This study shows that exposure to more years in education contributes to the rising prevalence of myopia. Increasing the length of time spent in education may inadvertently increase the prevalence of myopia and potential future visual disability.
Topics: Adult; Educational Status; Female; Humans; Male; Mendelian Randomization Analysis; Myopia; Prevalence; Refractive Errors; Risk Factors; United Kingdom
PubMed: 29875094
DOI: 10.1136/bmj.k2022 -
Current Opinion in Ophthalmology Jul 2017To evaluate the epidemiology of uncorrected refractive errors (URE) in adults both in the United States and globally, health outcomes impacted by URE, common barriers to... (Review)
Review
PURPOSE OF REVIEW
To evaluate the epidemiology of uncorrected refractive errors (URE) in adults both in the United States and globally, health outcomes impacted by URE, common barriers to treatment, and propose potential interventions.
RECENT FNDINGS
URE is the main cause of visual impairment and the second leading cause of blindness globally. Rates of URE are rising, and cause disability that reduces productivity, economic earnings, and the quality of life of affected individuals. Economic barriers, healthcare access, and sociocultural constraints are among the most fundamental barriers to correcting URE. However, innovative approaches are poised to lower rates of URE.
SUMMARY
URE is a leading cause of preventable visual impairment with serious health consequences. Numerous social and financial barriers are associated with the high prevalence of URE in low-income adults. Novel delivery programs for eyeglasses and programs to provide refractive surgery to correct refractive error could decrease rates of URE.
Topics: Age Factors; Blindness; Cost of Illness; Delivery of Health Care, Integrated; Health Services Accessibility; Humans; Income; Ophthalmology; Prevalence; Quality of Life; Refractive Errors; Socioeconomic Factors; United States
PubMed: 28379859
DOI: 10.1097/ICU.0000000000000376 -
Indian Journal of Ophthalmology 2012Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered... (Review)
Review
Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC), were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR) Development, Service Development and Social Entrepreneurship.
Topics: Global Health; Humans; Prevalence; Public Health; Refraction, Ocular; Refractive Errors; Vision, Low
PubMed: 22944755
DOI: 10.4103/0301-4738.100543 -
Indian Journal of Ophthalmology May 2019
Topics: Blindness; Global Health; Humans; Prevalence; Refraction, Ocular; Refractive Errors
PubMed: 31007210
DOI: 10.4103/ijo.IJO_762_19 -
Medicine Jul 2022To assess the most influential factor for pupil diameter changes among age, illuminance, and refractive state and reestablish the optimal procedures for clinical... (Observational Study)
Observational Study
To assess the most influential factor for pupil diameter changes among age, illuminance, and refractive state and reestablish the optimal procedures for clinical applications based on refractive state and illuminance for different age groups. The study was an observational study (repeated measure study). Participants included 219 Korean adults aged 20 to 69 years. Pupil diameters were measured using a pupilometer under scotopic, mesopic-low, and mesopic-high lighting conditions. Factor interactions among age, illuminance, and refractive state were evaluated using mixed linear model and chi-square automated interaction detection. Illuminance mainly contributed to variations in pupil diameter of participants over 50 years, whereas the refractive state was the dominant controlling factor for the pupil variation in participants below 50 years. For more generalized application, the pupil diameter decreased with older age and brighter illuminance (P < .001, inverse correlation, all comparisons). The mean pupil diameter was significantly higher in myopes and emmetropes than in hyperopes (P < .001). Pupil diameter variation modeled using the mixed model confirmed age, illuminance, and refractive error as significant factors (P < .001). Accounting for the interactions among age, illuminance, and refractive error and establishing their hierarchical dominance can be generalized using the chi-square automated interaction detection method and mixed model. Promoting age-dependent consideration for both illuminance and refractive state is necessary when pupil diameters play significant roles in clinical and manufacturing circumstances.
Topics: Adult; Age Factors; Humans; Lighting; Myopia; Pupil; Refractive Errors
PubMed: 35801739
DOI: 10.1097/MD.0000000000029859 -
BMJ Open Ophthalmology 2022Myopia is a global healthcare concern and effective analyses of dioptric power are important in evaluating potential treatments involving surgery, orthokeratology, drugs... (Review)
Review
Myopia is a global healthcare concern and effective analyses of dioptric power are important in evaluating potential treatments involving surgery, orthokeratology, drugs such as low-dose (0.05%) atropine and gene therapy. This paper considers issues of concern when analysing refractive state such as data normality, transformations, outliers and anisometropia. A brief review of methods for analysing and representing dioptric power is included but the emphasis is on the optimal approach to understanding refractive state (and its variation) in addressing pertinent clinical and research questions. Although there have been significant improvements in the analysis of refractive state, areas for critical consideration remain and the use of power matrices as opposed to power vectors is one such area. Another is effective identification of outliers in refractive data. The type of multivariate distribution present with samples of dioptric power is often not considered. Similarly, transformations of samples (of dioptric power) towards normality and the effects of such transformations are not thoroughly explored. These areas (outliers, normality and transformations) need further investigation for greater efficacy and proper inferences regarding refractive error. Although power vectors are better known, power matrices are accentuated herein due to potential advantages for statistical analyses of dioptric power such as greater simplicity, completeness, and improved facility for quantitative and graphical representation of refractive state.
Topics: Anisometropia; Humans; Myopia; Prescriptions; Refraction, Ocular; Refractive Errors
PubMed: 35452207
DOI: 10.1136/bmjophth-2021-000929 -
Bulletin of the World Health... 2001Recent data suggest that a large number of people are blind in different parts of the world due to high refractive error because they are not using appropriate... (Review)
Review
Recent data suggest that a large number of people are blind in different parts of the world due to high refractive error because they are not using appropriate refractive correction. Refractive error as a cause of blindness has been recognized only recently with the increasing use of presenting visual acuity for defining blindness. In addition to blindness due to naturally occurring high refractive error, inadequate refractive correction of aphakia after cataract surgery is also a significant cause of blindness in developing countries. Blindness due to refractive error in any population suggests that eye care services in general in that population are inadequate since treatment of refractive error is perhaps the simplest and most effective form of eye care. Strategies such as vision screening programmes need to be implemented on a large scale to detect individuals suffering from refractive error blindness. Sufficient numbers of personnel to perform reasonable quality refraction need to be trained in developing countries. Also adequate infrastructure has to be developed in underserved areas of the world to facilitate the logistics of providing affordable reasonable-quality spectacles to individuals suffering from refractive error blindness. Long-term success in reducing refractive error blindness worldwide will require attention to these issues within the context of comprehensive approaches to reduce all causes of avoidable blindness.
Topics: Amblyopia; Blindness; Eyeglasses; Global Health; Humans; Refractive Errors
PubMed: 11285669
DOI: No ID Found