Search

To determine the prevalence of myopia and hyperopia in Shahroud schoolchildren and their risk factors.Optometric examinations including the measurement of uncorrected and corrected visual acuity as well as non-cycloplegic and cycloplegic refraction using retinoscopy were done for students. Generalized Structural Equation Modeling (GSEM) was used to determine direct and indirect effects of independent variables on myopia and hyperopia.The data of 5581 students with a mean age of 9.24 ± 1.7 years were used in this study. The prevalence of myopia was 5.0% (95%CI: 4.3-5.7) and the prevalence of hyperopia was 4.8% (95%CI: 4.0 - 5.5) in all schoolchildren. According to the GSEM results, the odds of myopia in rural areas were 0.55 compared to urban areas. A one-unit increase in the ocular AL increased the odds of myopia by 4.91 times. The interaction of sex and age on myopia was significant such that in girls, the odds of myopia increased by 20% for every one-year increase in age while no significant change was seen in boys. A one-unit increase in the ocular AL decreased the odds of hyperopia by 0.49 times. Moreover, the interaction of outdoor activity hours and sex on the prevalence of hyperopia was significant such that increased outdoor activity reduced the odds of hyperopia in girls while no significant correlation was found in boys.Myopia and hyperopia had moderate prevalence. Axial Length had the largest direct association on myopia and hyperopia. Age and outdoor activity had weak associations on refractive errors.

Objective To investigate the distribution of refractive errors and their association with ocular biometric data, family history and environment variables in medical university students of first to six semesters of UNIVAG - MT. Methods A general ophthalmological exam was performed including, corneal topography, and ocular optical biometry. Lens power has calculated by Bennett and Rozema’s formula. A questionnaire regarding family history of myopia and lifestyle visual activities was applied. Only university students with normal ophthalmological exams were included. Statistical significance was considered at the level of p Results One hundred twenty-eight students were selected, whereas other 13 were excluded. The mean age was 21.28 ± 2.18 years. Forty-four (34.4%) participants were males. Regarding refractive errors, 18 (14.1%) were hyperopic, 41 (32%) were emmetropic, 61 (47.7%) were myopic, and 8 (6.3%) were high myopic. The mean and standard deviations of spherical equivalents, axial lengths, keratometries (K1 and K2), and lens powers were -1.27 ± 2.21 D, 24.17 ± 1.07 mm, 42.90 ± 1.25 D, 43.94 ± 1.37 D, and 22.62 ± 1.73 D, respectively. In relation to the family history of myopia, one parent was myopic in 28 (50%) of subjects, and both parents were myopic in 7 (12.5%) subjects. The average of hours per week spent outdoors were 5.82 +/- 7.38 hs. and spent 6.85 +/- 6.26 hs. at sports activities at night. Conclusion Myopia was the most frequent refractive error among the medical university students subject of this study, and was approximately three times higher than those reported for other samples of Brazilian population. There was a positive correlation between refraction errors and axial length.

Myopia typically starts and progresses during childhood, but onset and progression can occur during adulthood. The goals of this review are to summarize published data on myopia onset and progression in young adults, aged 18 to 40 years, to characterize myopia in this age group, to assess what is currently known, and to highlight the gaps in the current understanding. Specifically, the peer-reviewed literature was reviewed to: characterize the timeline and age of stabilization of juvenile-onset myopia; estimate the frequency of adult-onset myopia; evaluate the rate of myopia progression in adults, regardless of age of onset, both during the college years and later; describe the rate of axial elongation in myopic adults; identify risk factors for adult onset and progression; report myopia progression and axial elongation in adults who have undergone refractive surgery; and discuss myopia management and research study design. Adult-onset myopia is common, representing a third or more of all myopia in western populations, but less in East Asia, where onset during childhood is high. Clinically meaningful myopia progression continues in early adulthood and may average 1.00 diopters (D) between 20 and 30 years. Higher levels of myopia are associated with greater absolute risk of myopia-related ocular disease and visual impairment, and thus myopia in this age group requires ongoing management. Modalities established for myopia control in children would be options for adults, but it is difficult to predict their efficacy. The feasibility of studies of myopia control in adults is limited by the long duration required.

To investigate the effect of tutorial classes and schooling schedule in childhood on age of myopia onset.Refractive data for subjects ≥18 years of age were collected from 8 dispensing opticians or refractive ophthalmologists' offices in Argentina. Age of myopia onset, spherical equivalent (SE), and risk factors were determined using questionnaires. Multiple linear regression models were applied to assess possible factors associated with age of myopia onset or final adult SE.A total of 274 adults (61.3% females) with myopia between -0.50 and -6.00 D were included. Mean age was 36.9 ± 14.5 years. The mean adult SE was -2.95 ± 1.45 D, and the mean age of myopia onset was 14.2 ± 5.4 years. Subjects that attended after-school tutorial classes (β = -2.23; P = 0.005) or a full day schedule in primary school (β = -1.07; P = 0.035) or that spent more time on near work (β = -0.70; P = 0.010) in childhood, had younger age of myopia onset.In our study cohort, adults that had attended tutorial classes and/or full-day schooling during childhood had younger age of myopia onset.

Increased levels of outdoor light have been found to be associated causally with decreased rates of myopia. The goal of this study was to measure the effect of indoor nursery school light intensity on refraction of preschool children in Israel.A total of 1596 children aged 4 to 5 years from 27 nursery schools were examined. Light intensity was tested with a luxmeter device (Lux) inside and outside the nursery school. Noncycloplegic refractions were measured with the PlusOptix vision A09 screening device. Data analysis was performed using Pearson coefficients, chi-square tests for proportions and ANOVA tests by tertiles of illuminance.This study included 1131 kindergarten children with a mean age of 4.87 ± 0.33 years, of which 571 were female (50.5%). The mean light intensity of the low, medium, and high intensity groups differed significantly (ANOVA P 0.001) at 359 ± 2.64 lux (range 264-431), 490 ± 2.21 lux (range 432-574), and 670.76 ± 3.73 lux (range 578-804), respectively. Mean spherical equivalent (SE) was +0.56 ± 0.03D for the low-intensity group, +0.73 ± 0.03D for the medium-intensity group, and +0.89 ± 0.03D for the high-intensity group (ANOVA P 0.001). The low-intensity group had 42.1% of children with zero refraction or less, while the high-intensity group had 19.3%.In the nursery schools, lower amounts of illumination were associated with less hyperopic refractive error. As the low hyperopic reserve is a risk factor for developing myopia, this finding needs to be followed up to establish whether this association reflects a causal relationship, which could be modulated for the prevention of myopia.

This study assessed the causes of visual impairment over a decade in Buenos Aires City. This is a retrospective case series where we reviewed the database of visual disability certificates issued by the Buenos Aires City Ministry of Health between 2009 and 2017. In Argentina, visual disability is defined as a visual acuity = 20/200 in the better eye, or a corresponding visual field of less than 20 degrees in the less impaired eye. The database included the following variables: year of issue, age, gender, and cause of visual disability. Between 2009 and 2017 a total of 7656 subjects were certified as legally blind. The mean age of the sample was 57 ± 21 years and 52.1% were females. The emission was near 700 certificates per year. The age distribution showed that 62.8% of certificates were from patients older than 50 years and that only 6.6% were given to subjects under 20. The leading causes of visual disability in Buenos Aires City were age-related macular degeneration (ARMD) with a rate of 15.5%, degenerative myopia (14.4%), primary open-angle glaucoma (11.3%) and diabetic retinopathy (6.6%). In subjects younger than 50, degenerative myopia was the first cause of visual disability. Interestingly in Argentina, where the prevalence of myopia is low, degenerative myopia is found to be the major cause of visual disability in middle-aged adult subjects. Population and clinical methods to avoid this preventable disease should need to be implemented as a matter of urgency.Este trabajo estudia las causas de la discapacidad visual durante una década en la Ciudad de Buenos Aires. Se presenta una serie de casos retrospectiva donde se revisó la base de datos de certificados de discapacidad visual emitidos por el Ministerio de Salud de la Ciudad de Buenos Aires entre 2009 y 2017. En Argentina, la discapacidad visual se define como una agudeza visual = 20/200 en el mejor ojo, o un campo visual correspondiente de menos de 20 grados en el ojo menos deteriorado. La base de datos incluyó las siguientes variables: año de emisión, edad, sexo y causa de la discapacidad visual. Entre 2009 y 2017 se certificaron un total de 7656 sujetos con ceguera legal. La edad media de la muestra fue de 57 ± 21 años y el 52.1% fueron mujeres. La distribución por edades mostró que el 62.8% de los certificados fueron dados a pacientes mayores de 50 años y que solo el 6.6% se otorgó a menores de 20 años. Las principales causas de discapacidad visual fueron la degeneración macular asociada a la edad (DMAE) (15.5%), la miopía degenerativa (14.4%), el glaucoma primario de ángulo abierto (11.3%) y la retinopatía diabética (6.6%). En los menores de 50 años, la miopía degenerativa fue la primera causa de discapacidad visual. Resulta interesante que, en Argentina, donde la prevalencia de miopía es baja, la miopía degenerativa sea la principal causa de discapacidad visual en adultos de mediana edad.

Purpose This study was developed to explain the extraordinary rise in myopia prevalence beginning after 1950 in Indigenous Arctic communities considering recent findings about the risk factors for school myopia development. Myopia prevalence changed drastically from a historical low of less than 3% to more than 50% in new generations of young adults following the Second World War. At that time, this increase was attributed to concurrent alterations in the environment and way of life which occurred in an aggressive programme of de-culturalization and re-acculturation through residential school programmes that introduced mental, emotional and physical stressors. However, the predominant idea that myopia was genetic in nature won the discussion of the day, and research in the area of environmental changes was dismissed. There may have also been an association between myopia progression and the introduction of extreme mental, emotional and physical stressors at the time. Recent findings Since 1978, animal models of myopia have demonstrated that myopiagenesis has a strong environmental component. Furthermore, multiple studies in human populations have shown since 2005 how myopia could be produced by a combination of limited exposure to the outdoors and heavy emphasis on academic subjects associated with intense reading habits. This new knowledge was applied in the present study to unravel the causes of the historical myopia epidemics in Inuit communities. After reviewing the available published data on myopia prevalence in circumpolar Inuit populations in the 20th century, the most likely causes for the Inuit myopia epidemic were the combination of increased near work (from almost none to daily reading) and the move from a mostly outdoor to a much more indoor way of life, exacerbated by fewer hours of sunshine during waking hours, the lower illuminance in the Arctic and the extreme psychophysical stress due to the conditions in the Residential Schools.

There are fundamental differences between East and West about how the Elements and Activities that conform the Universe are concieved. Greeks studied four elements and Chinese developed a Five Movement Theory. The five senses were also different for Chinese doctors: hear, sight, taste, smell and diction (speaking). The inclusion of “speaking” among the senses suggests that early Chinese doctors and philosophers looked at the activities that humans develop instead of thinking that humans passively sense and then have motor responses. This is discussed in the context of both cultures and associated with the ideas Chinese had about emotions in clinical practice.

Purpose: To determine whether the progression of myopia in children is faster during school closures and home confinement during the COVID-19 pandemic. Methods: This was a case series study collecting retrospective data of refractive error during 2019 and 2020 in consecutive myopic patients attending regular checkups for their spectacle prescription. Inclusion criteria were spherical equivalent between -0·50 and -6·00 diopters (5-18 years of age) consulting from September to December 2020. Patients receiving any treatment for arresting myopia progression were excluded. Cycloplegic spherical equivalent in both eyes was recorded for 2018, 2019 and 2020. Mean progression over the two periods 2018-2019 and 2019-2020 was calculated. Results: At the 2020 visit after confinement, mean age of the 115 enrolled patients was 11·89 ± 3·68 years and 60·0% were girls. The mean annualized progression for the right eyes in 2019 was 0·44±0·52 D and increased to 0·58±0·53 D in 2020 during the period that included home confinement (p = 0·0019). Conclusion: Mean annual progression rates during strict pandemic home confinement was faster than in the previous year, in contrast to the general slowing of progression as children get older. Funding Statement: None. Declaration of Interests: None of the authors have any proprietary interests or conflicts of interest related to this submission. Ethics Approval Statement: The Ethics Committee of the Argentinian Council of Ophthalmology gave approval for this study.

Purpose To document one-year changes in refraction and refractive components in preschool children. Methods Children, 3-5 years old, in the Jiading District, Shanghai, were followed for one year. At each visit, axial length (AL), refraction under cycloplegia (1% cyclopentolate), spherical dioptres (DS), cylinder dioptres (DC), spherical equivalent refraction (SER) and corneal curvature radius (CR) were measured. Results The study included 458 right eyes of 458 children. The mean changes in DS, DC and SER were 0.02 +/- 0.35 D, -0.02 +/- 0.33 D and 0.01 +/- 0.37 D, while the mean changes in AL, CR and lens power (LP) were 0.27 +/- 0.10 mm, 0.00 +/- 0.04 mm and - 0.93 +/- 0.49 D. The change in the SER was linearly correlated with the baseline SER (coefficient = -0.147, p < 0.001). When the baseline SER was at 1.05 D (95% CI = 0.21 to 2.16), the change in SER was 0 D. The baseline SER was also linearly associated with the change in LP (coefficient = 0.104, p = 0.013), but not with the change in AL (p = 0.957) or with the change in CR (p = 0.263). Conclusion In eyes with a baseline SER less than +1.00 D, LP loss was higher compared to axial elongation, leading to hyperopic shifts in refraction, whereas for those with baseline SER over this range, loss of LP compared to axial elongation was reduced, leading to myopic shifts. This model indicated the homeostasis of human refraction and explained how refractive development leads to a preferred state of mild hyperopia.

PurposeTo explore the relationship between intraocular pressure (IOP) at baseline and myopia progression in Chinese children from the Anyang Childhood Eye Study.DesignProspective school-based cohort study.MethodsA total of 1558 grade 7 students completed the entire 2-year study. Ocular biometry, cycloplegic refractions and pneumotonometry were performed. Three years of follow-up have been completed for the children aged 12 years. The refractive groups and the tertiles of IOP were assessed by analysis of variance, to look for differences in mean values of spherical equivalent and IOP, respectively.ResultsThe children’s mean baseline IOP was 15.87±3.42 mm Hg. Mean IOP was significantly higher in girls by 0.57 mm Hg (p=0.024). In the whole sample, there was a mean change in spherical equivalent of −1.05 D over 2 years. The baseline IOP was 15.69 mm Hg in those progressing 1 D or more vs 16.09 mm Hg for those progressing 1 D had mean IOP of 15.94 vs 16.42 mm Hg for those myopes progressing 1 D or less (p=0.024).ConclusionsIn this sample of Chinese children, myopia progression over 2 years was inversely related to IOP, suggesting that IOP had essentially no relationship with myopia progression in school children. The lower IOP in progressing myopic eyes may indicate more compliant sclerae.

AimsTo evaluate lens power (LP) in schoolchildren aged 6–12 years.MethodsThis cross-sectional study was conducted in Shahroud, northeast Iran. The students were selected through random cluster sampling and underwent the measurements of biometry, uncorrected and corrected visual acuity, non-cycloplegic and cycloplegic refraction. The LP was calculated using the Bennett formula.ResultsOf 6624 invited children, 5620 (84.8%) participated in the study and data of 4870 children were finally analysed. The mean age of the participants was 9.7 years and 2277 participants (46.02%) were girls. The mean LPs were 22.86 dioptres (D) in total study population, 23.91 D in 6 and 22.10 D in 12-year-old children. The mean LP was higher in girls than boys (23.48 D vs 22.34 D), in rural children than urban children (23.17 D vs 22.83 D) and in children with hyperopia (23.25 D) than children with myopia or emmetropia (22.64 D and 22.86 D, respectively). In the multiple linear regression model, lens thickness (β=1.59, pConclusionLP decreased with age between 6 and 12 years and was associated with a shorter AL, deeper ACD, higher SE, thicker lens and lower CP.

PURPOSE. We studied biometry changes before and after myopia onset in a cohort of Singaporean children. METHODS. All data were taken from the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Participants underwent refraction and biometry measurements with a follow-up of 3 to 6 years. The longitudinal ocular biometry (spherical equivalent refraction, axial length, and lens power) changes were compared between children who suffered myopia during the study (N = 303), emmetropic children (N = 490), and children myopic at baseline (N = 509). RESULTS. At myopia onset, the myopic shift increased to 0.50 diopters (D)/y or more in new myopes compared to the minor changes in emmetropes of the same age. New myopes had higher axial growth rates than emmetropes, even years before myopia onset (0.37 and 0.14 mm/y, respectively; ANOVA with Bonferroni post hoc test, P < 0.001). After onset, the change in both parameters slowed down gradually, but significantly (P < 0.05). In new myopes, lens power loss (-0.71 D/y) was significantly higher up to 1 year before myopia onset compared to emmetropes (-0.46 D/y), after which lens power loss slows down rapidly. At age 7 years, (future) new myopes had lens power values close to those of emmetropes (25.12 and 25.23 D, respectively), while later these values approached those of children who were myopic at baseline (23.06 and 22.79 D, respectively, compared to 23.71 D for emmetropes; P < 0.001). CONCLUSIONS. New myopes have higher axial growth rates and lens power loss before myopia onset than persistent emmetropes.

Background To assess 5-year refractive changes and their related factors in the 40- to 64-year-old population of Shahroud, Iran. Design Prospective cohort study. Participants Of the 5190 participants of Phase I, 4737 participated in Phase II (response rate = 91.3%). Methods Participants were tested by refraction, visual acuity, slit-lamp biomicroscopy, ophthalmoscopy and biometry. Myopia was defined as a spherical equivalent more negative than -0.5 dioptre (D) and hyperopia as a spherical equivalent more positive than +0.5 D. Main outcome measures Mean 5-year change in spherical equivalent refraction. Results The mean 5-year change in spherical equivalent refraction was +0.24 D (95% CI: +0.22 to +0.25). After 5 years, 4.77% (95% CI: 4.08 to 5.46) of subjects developed at least 0.5 D of myopia and 22.27% (95% CI: 20.97 to 23.57) developed at least 0.5 D of hyperopia. Five-year changes in refraction included a hyperopic shift in all age groups. The greatest hyperopic shift was seen in middle-aged women. The greatest loss of lens power was observed in hyperopic women and the least in myopic men. Nuclear cataract was associated with a myopic shift in refraction. The axial length and the corneal power had very small changes during this period. Myopes showed the greatest increase in axial length. Corneal power increased by a very small amount in all refractive groups. Conclusions The most important biometric index related to hyperopic shifts, which were greater in magnitude in women, was loss of lens power, whereas nuclear cataract was associated with myopic shifts.

Many studies on children have shown that lack of cycloplegia is associated with slight overestimation of myopia and marked errors in estimates of the prevalence of emmetropia and hyperopia. Non-cycloplegic refraction is particularly problematic for studies of associations with risk factors. The consensus around the importance of cycloplegia in children left undefined at what age, if any, cycloplegia became unnecessary. It was often implicitly assumed that cycloplegia is not necessary beyond childhood or early adulthood, and thus, the protocol for the classical studies of refraction in older adults did not include cycloplegia. Now that population studies of refractive error are beginning to fill the gap between schoolchildren and older adults, whether cycloplegia is required for measuring refractive error in this age range, needs to be defined. Data from the Tehran Eye Study show that, without cycloplegia, there are errors in the estimation of myopia, emmetropia and hyperopia in the age range 20-50, just as in children. Similar results have been reported in an analysis of data from the Beaver Dam Offspring Eye Study. If the only important outcome measure of a particular study is the prevalence of myopia, then cycloplegia may not be crucial in some cases. But, without cycloplegia, measurements of other refractive categories as well as spherical equivalent are unreliable. In summary, the current evidence suggests that cycloplegic refraction should be considered as the gold standard for epidemiological studies of refraction, not only in children, but in adults up to the age of 50.

Purpose: To explore the relationship between lens power and refractive error in older adults following age-related hyperopic shifts. Methods: From the Shahroud Eye Cohort Study, subjects aged 55-64 years without clinically significant cataracts (with nuclear opacity of grade 0 to 1) were included to maximize the proportion of subjects with age-related hyperopic shifts that normally occur between 40 to 60 years of age, before interference from the myopic shift due to nuclear cataracts. Mean axial length (AL) values, corneal power, anterior chamber depth, lens thickness, and lens power were analyzed and compared among three refractive groups (myopes, emmetropes, and hyperopes). Results: A total of 1,006 subjects including 496 (49.63%) male subjects were studied. Corneal power was similar in all refractive groups. Hyperopes had + 1.69 diopters higher mean spherical equivalent refractive error and − 0.50 mm shorter AL than emmetropes. Myopes had 0.67 mm longer AL than emmetropes. Hyperopes had significantly increased lens thickness as compared to emmetropes (4.42 vs. 4.39 mm respectively). In this adult sample, the hyperopic group had lower lens power (+22.29 diopters vs. +22.54 diopters in emmetropes, P = 0.132). Myopes had similar lens power as emmetropes. Conclusion: Axial length is the principal determinant of refractive errors. Lens power may have importance in determining hyperopia in adults free of cataract.

This paper customizes Bennett's equation for calculating lens power in chicken eyes from refraction, keratometry and biometry. Previously published data on refraction, corneal power, anterior chamber depth, lens thickness, lens radii of curvature, axial length and eye power in chickens aged 10-90 days were used to estimate Gullstrand's lens power and Bennett's lens power for chicken eyes, and to calculate the lens equivalent refractive index. Bennett's A and B constants for the front and back surface powers of the lens were calculated for data measured from day 10 to 90 at 10 day intervals, and mean customized constants were calculated. The mean customized constants for Bennett's equation for chicks were A = 0.574 +/- 0.023 and B = 0.379 +/- 0.021. As found previously, lens power decreases with age in chicks, while corneal power decreases and axial length increases. The lens equivalent refractive index decreases with age from 10 to 90 days after hatching. Bennett's equation can be used to calculate lens power in chicken eyes for studies on animal myopia, using standard biometry. (C) 2014 Elsevier B.V. All rights reserved.

Background: Refractive errors are among the most frequent reasons for demand of eye-care services. Publications on refractive errors prevalence in our country are few. This study has the purpose to assess the prevalence of refractive errors in an adult population of Villa Maria, Córdoba, Argentina. Methods: The Villa Maria Eye Study is a population-based cross-sectional study conducted in the city of Villa Maria, Córdoba, Argentina from May 2008 to November 2009. Subject’s aged 40+ received a demographic interview and complete ophthalmological exam. Visual acuity was obtained with an ETDRS chart. Cycloplegic auto refraction was performed. The spherical equivalent was highly correlated between right and left eyes, so only data of right eyes are presented. Myopia and hyperopia were defined with a ±0.50 diopters (D) criterion and astigmatism >1 D. Results: This study included 646 subjects, aged 40 to 90 (mean age: 59.6±10.3 years old). Four hundred and sixty two (71.5%) were females. The mean spherical equivalent was +0.714±2.41 D (range, −22.00 to +8.25 D) and the power of the cylinder was, on average, −0.869±0.91 D (range, 0 to −6.50 D). In this sample, 61.6% subjects were hyperopic, and 13.5% were myopic. Myopia prevalence was lower in men (9.8% versus 14.9%) but this difference among genders was not statistically significant. There were 141 subjects (21.8%) with anisometropia greater than 1 D, and 168 subjects (26.0%) with astigmatism greater than 1 D. Conclusions: The present study shows the prevalence of cycloplegic refractive errors in an adult population of Argentina. The prevalence of hyperopia was high, while myopia prevalence was very low. Fil: Sánchez, María Victoria. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Iribarren, Rafael. Department Of Ophthalmology. Centro Médico San Luis; Argentina Fil: Latino, Santiago G.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Torres, Victor Eduardo Roque. Universidad Nacional de Córdoba. Facultad de Cs.económicas. Instituto de Estadística y Demografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentina Fil: Gramajo, Ana L.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Artal, María N.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Yadarola, María B.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Garay, Patricia R.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Luna, José D.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina Fil: Juarez, Claudio P.. Fundacion Ver, Centro Privado de Ojos Romagosa; Argentina

To analyze the components of young Chinese eyes with special attention to differences in corneal power, anterior segment length and lens power. Cycloplegic refractions and ocular biometry with LENSTAR were used to calculate lens power with Bennett’s method. Mean refraction and mean values for the ocular components of five different refractive groups were studied with ANOVA and post-hoc Scheffé tests. There were 1889 subjects included with full data of refraction and ocular components. As expected, mean axial length was significantly longer in myopic eyes compared to emmetropes. Girls had steeper corneas, more powerful lenses and shorter eyes than boys. Lens power was lower in boys and also lower in myopic eyes. Lens thickness was the same for both genders but was lower in myopic eyes. Although cornea was steeper in myopic eyes in the whole sample, this was a gender effect (more girls in the myopic group) as this difference disappeared when the analysis was split by gender. Anterior segment length was longer in myopic eyes. In conclusion, myopic eyes have lower lens power and longer anterior segment length, that partially compensate their longer axial length. When analyzed by gender, the corneal power is not greater in low and moderate myopic eyes.

To assess 5-year refractive changes and their related factors in the 40- to 64-year-old population of Shahroud, Iran.Prospective cohort study.Of the 5190 participants of Phase I, 4737 participated in Phase II (response rate = 91.3%).Participants were tested by refraction, visual acuity, slit-lamp biomicroscopy, ophthalmoscopy and biometry. Myopia was defined as a spherical equivalent more negative than -0.5 dioptre (D) and hyperopia as a spherical equivalent more positive than +0.5 D.Mean 5-year change in spherical equivalent refraction.The mean 5-year change in spherical equivalent refraction was +0.24 D (95% CI: +0.22 to +0.25). After 5 years, 4.77% (95% CI: 4.08 to 5.46) of subjects developed at least 0.5 D of myopia and 22.27% (95% CI: 20.97 to 23.57) developed at least 0.5 D of hyperopia. Five-year changes in refraction included a hyperopic shift in all age groups. The greatest hyperopic shift was seen in middle-aged women. The greatest loss of lens power was observed in hyperopic women and the least in myopic men. Nuclear cataract was associated with a myopic shift in refraction. The axial length and the corneal power had very small changes during this period. Myopes showed the greatest increase in axial length. Corneal power increased by a very small amount in all refractive groups.The most important biometric index related to hyperopic shifts, which were greater in magnitude in women, was loss of lens power, whereas nuclear cataract was associated with myopic shifts.

Purpose: To determine the sensitivity and specificity of noncycloplegic autorefraction for determining refractive status compared to cycloplegic autorefraction. Methods: The target population was noninstitutionalized citizens of all ages, residing in Tehran in 2002, selected through stratified cluster sampling. From 6497 eligible residents, 70.3% participated in the study, from August to November 2002. Here, we report data on 3501 people over the age of 5 years who had autorefraction with and without cycloplegia (two drops of cyclopentolate 1.0% 5 min apart, with autorefraction 25 min after the second drop). Results: Overall, the sensitivity of noncycloplegic autorefraction for myopia was 99%, but the specificity was only 80.4%. In contrast, the sensitivity for hyperopia was only 47.9%, but the specificity was 99.4%. At all ages, noncycloplegic autorefraction overestimated myopia and underestimated hyperopia. Overestimation of myopia was highest in the 21–30 and 31–40 year groups. Underestimation of hyperopia was high up to the age of 50 (20–40%), but decreased with age, to about 8% after the age of 50, down to almost 0% after 70. The difference in mean spherical equivalent with and without cycloplegia fell from 0.71 dioptres (D) in the 5–10 age group to 0.14D in those over 70. Conclusion: Use of noncycloplegic autorefraction in epidemiological studies leads to considerable errors relative to cycloplegic measurements, except in those over 50–60. The difference between cycloplegic and noncycloplegic measurements varies with age and cycloplegic refractive category, and there is considerable individual variation, ruling out adjusting noncycloplegic measurements to obtain accurate cycloplegic refractions.

Purpose: This study explores the natural history of hyperopic refractive error in relation to the recalled age of first distance prescription.Methods: A population of adult office workers, coming for a general health check-up without refractive selection, completed a questionnaire about age of first distance prescription and were refracted by an ophthalmologist with non-cycloplegic subjective procedures. Hyperopia was defined as a spherical equivalent of +0.75 diopters or more. This study included 145 hyperopes aged 50–65 years at interview.Results: The hyperopic subjects were first prescribed spectacles for distance vision in a broad spectrum of ages, from early childhood to adulthood. The subjects with older ages of first prescription tended to develop lower amounts of refractive error but this relation was not significant (Spearman’s rho −0.126, p = 0.131).Conclusions: The age of first spectacle prescription in hyperopes is not strongly related to the final refractive error developed in adulthood.

This study explores the relationship between the recalled age of first distance prescription and the final myopic refractive error developed in adults.Adult office workers, sent for a general health check-up without refractive selection, completed a questionnaire about age of first distance prescription, years of university study, and parental history of myopia, and were subjectively refracted by an ophthalmologist.Average age of the 397 consecutive myopic subjects was 42.6 +/- 9.6 years and 80.6% were males. The median age of first prescription was 20 years. In the group with earlier first distance prescription (ages 3 to 10), 25.6% developed low final refractive errors (-0.50 to -3.0 diopters), 38.5% developed moderate myopia (-3.0 to -6.0 diopters), and 35.9% developed high myopia (-6.0 diopters), while in the groups with later first distance prescription (ages 23 to 30), 90-100% developed low final refractive errors.Subjects developing myopia after age 20 had low myopia. Those subjects with an early recalled age of first prescription had a broad spectrum of myopic refractive errors, including a high proportion (approximately 2/3) of moderate to high myopia, and approximately 1/3 of low myopia.

PURPOSE We assessed changes in the position of the lens with aging in a general population. METHODS The population-based Central India Eye and Medical Study included 4711 subjects. As part of an ophthalmic examination, anterior segment length (ASL) was measured sonographically and calculated as anterior chamber depth plus lens thickness. Subjects with nuclear cataract grades 5 or more (43.9% of the sample) were excluded. RESULTS The study included 2468 subjects (1176 [47.6%] men) with a mean age of 41.2 ± 8.5 years (range, 30-78 years) and mean axial length of 22.68 ± 0.81 mm (range, 19.89-31.02 mm). In multivariate analysis, longer ASL was associated with older age (P = 0.04; correlation coefficient B, 0.002; 95% confidence interval [CI], 0.000, 0.005) after adjusting for male sex (P < 0.001), longer axial length (P < 0.001), higher degree of nuclear cataract (P = 0.001), and higher body mass index (P = 0.02). Greater lens thickness was associated with older age (P < 0.001; B, 0.009; 95% CI, 0.007, 0.0011) after adjusting for male sex (P < 0.001), shallower anterior chamber depth (P < 0.001), and higher degree of nuclear cataract (P < 0.001). Deeper anterior chamber depth was associated with younger age (P < 0.001; B, -0.007; 95% CI, -0.008, -0.005) after adjusting for male sex (P < 0.001), thinner lens thickness (P < 0.001), and longer axial length (P < 0.001). Combining both analyses revealed that for each year increase in age, lens thickness increased by 0.009 mm, anterior chamber depth decreased by 0.007 mm, the posterior lens pole moved backward by 0.002 mm, and the lens center moved forward by 0.0025 mm. CONCLUSIONS Increasing age before the development of cataract is associated with a slight forward movement of the lens center, adding to the lens paradox.

High myopia is a major cause of uncorrectable visual impairment. It imposes major challenges and costs for refractive correction, and for the treatment of associated pathological complications. In the last 60 years, there has been a marked increase in the prevalence of high myopia in younger generations in developed countries in East and Southeast Asia, and there are signs of similar, but less pronounced increases in North America and Europe. In some parts of the world, 70-90% of children completing high schools are now myopic, and as many as 20% may be highly myopic. It is now clear that myopia results from excessive axial elongation of the eye, and this greater rate of axial elongation appears to be environmentally driven. Experimental studies have examined the biochemical mechanisms involved in regulation of axial elongation; and, from these studies, some options have emerged for preventing the development of myopia or slowing myopia progression. Atropine eye drops have been quite extensively used in clinical practice in Asian countries. This long-lasting treatment could be beneficial, but has clear limitations and complications. Recent reports suggest that a low concentration of atropine, which has less severe side-effects, is also effective. But, a decision to use an invasive treatment such as atropine drops, even at low doses, requires careful consideration of the risk of myopia progression. A decision to use atropine in pre-myopic patients would require even more careful consideration of the risks. Here, we review the current literature relevant to the prevention of myopia progression with atropine drops.

This work studies ethnic and geographical differences in the age-related straylight increase by means of a stochastic model and unpublished lens opacity data of 559 residents of Villa Maria (Argentina), as well as data of 912 Indonesian subjects published previously by Husain et al. For both cohorts the prevalence of each type and grade of lens opacity was determined as a function of age, from which a stochastic model was derived capable of simulating the lens opacity prevalence for both populations. These simulated lens opacity data were then converted to estimated straylight by means of an equation derived from previously recorded data of 107 eyes with varying degrees of cataract. Based on these opacity templates 2500 random sets of subject age and lens opacity data were generated by the stochastic model for each dataset, from which estimated straylight could be calculated. For the Argentinian data the estimated straylight was found to closely resemble the published models for age-related straylight increase. For younger eyes the straylight variation of the model was the same as what was previously published (in both cases 0.200 log units), which doubled in size for older eyes. For the Indonesian data, however, this age-related straylight increase was found to be fundamentally different from the published age model. This suggests that current normative curves for age-related straylight increase may not always be appropriate for non-European populations, and that the inter-individual straylight variations in young, healthy eyes may possibly be due to variations in lens opacities. (C) 2015 Elsevier Ltd. All rights reserved.

Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract. The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study. As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life.

The present study was developed to assess prevalence of myopic refractive error and the relative percentages of youth- and adult- onset myopia in a Caucasian adult population.Subjects were office-workers sent consecutively from their workplace for a general health check-up, without refractive selection. Each subject received a questionnaire about academic achievement and family history of myopia. Subsequently, an ophthalmologist performed the vision examination. Although age of initial lens use is not necessarily the same as age of onset of myopia, it was considered to be so for this paper. A subject was considered an adult-onset myope if lens use began at age 18 or later.Subjects (n=349) had a mean age of 37.6 +/- 9.3 years. One hundred seventeen subjects (33.5% prevalence) had myopic spherical equivalent refraction. Further analysis comprises only subjects with simple myopia (astigmatism1 diopter, n=95). Nearly half of the simple myopic subjects were of adult-onset (47.8%). There was no difference in family history of myopia between youth- and adult-onset myopes (at least one myopic parent in 53.1% and 47.8% respectively, p=0.53), and no clear cut-off point separated the two myopic subgroups with respect to the age of lens use onset. However, adult-onset myopes had myopia of lower diopter amount than youth-onset myopes.Adult-onset myopes comprised nearly half of the simple myopic subjects, and their family history of myopia was similar to that of youth-onset myopes. There is no clear cut-off point between both myopic subgroups when age of onset is the variable considered.

A retrospective study was developed to evaluate risk factors in adult-onset myopia.Subjects included were 25 to 35 years old. There were 116 non-myopic subjects in the control group and 66 myopic subjects with first lens prescription at age 17 or later. Subjects received a questionnaire about academic achievement, daily hours of reading during years of study, and family history of myopia.The level of academic achievement was similar for myopic and non-myopic groups in this sample. Myopia was associated with family history (chi(2) = 6.131, p/= 0.013) and with daily hours of reading during years of study (chi(2) = 3.904, p/= 0.048). According to multiple logistic regression analysis, the correlation of myopia with family history adjusted for daily hours of reading remained significant (p/= 0.005), whereas the correlation with daily hours of reading adjusted for family history was not significant (p/= 0.061).After multivariate analysis, adult-onset myopia was significantly associated only with family history of myopia.

Purpose: To investigate quantitatively in young adults therelationship between long-term cumulative nearwork, degradation ofdynamic accommodative ability and the presence of asthenopic symptoms. Methods: Subjects consistedof 87 young students and office workers between 18 and 31 years of age with uncorrectedvisual acuity of 20/30 or better in each eye. The amounts of nearwork, dynamic accommodativefacility, and level of asthenopic symptoms were measured for each subject. Results:Total cumulative nearwork time was negatively correlated with accommodative facilityand positively correlated with the number of asthenopic symptoms. Furthermore,significant correlations were found between total nearwork time and blurred vision, andblurred vision and reduced accommodative facility. Moreover, the sub-category of ``hoursspent reading over the years'' was found to be significantly correlated with decreasedaccommodative facility. Conclusions: The correlations suggest a relationship betweencumulative amount of nearwork, decreased accommodative facility and asthenopia.

Modern cataract surgery by phacoemulsification is a widely accepted procedure with a rapid recovery time. The prescription of specific intraocular lens, implanted during surgery, makes it possible to anticipate whether the patient will need reading glasses after the procedure. The present study analyses a sample of cataract surgery patients to show the frequency of myopic shifts related to nuclear opacity, which can result in clear near vision before surgery. A non-selected sample of consecutive patients who underwent elective cataract surgery in a private clinic was studied retrospectively. The myopic shift in refraction was assessed by comparing the old prescription with the spectacle correction at the time of interviewing.The mean age of the 229 subjects studied was 71.5 ± 10.4 years (109, 47.6%, males). A myopic shift in refraction, defined as at least - 0.5 diopters, was present in 37.1% of subjects (95% CI: 30.8%-43.4%). The mean change in refraction in these subjects was -2.52 ± 1.52 diopters. The percentage of subjects who had developed a myopic shift was significantly greater in those who presented greater nuclear opalescence. There were also differences in the mean myopic shift by refractive group, with the emmetropes having the greatest myopic shift. In this study of patients seeking cataract surgery in a clinical setting, more than one third had myopic shifts in refraction. This must be taken into account in order that patients maintain the benefit of clear near vision after surgery.

PURPOSE Although corneal power and axial length are known to be inversely correlated, the biological determinants of corneal power are unknown. To elucidate this correlation further, study authors investigated the relationships among corneal power, corneal diameter, anterior chamber diameter, and axial length in a sample of human adults. METHODS The eyes of 61 subjects seen consecutively in an eye clinic were studied with a high-resolution optimal coherence tomography (OCT) pachymetry device and ophthalmic optical biometer. The relationships between corneal power, white-to-white (WTW) corneal diameter, anterior chamber diameter, and axial length were assessed with Pearson correlations. RESULTS The mean age of the 61 subjects was 48.7 ± 19.4 years. Corneal power was negatively correlated with axial length (r = -0.303, P < 0.01); WTW corneal diameter (r = -0.399, P < 0.001); and most interestingly, anterior chamber diameter (r = -0.646, P < 0.001). There was also a positive correlation between anterior chamber diameter and axial length (r = 0.489, P < 0.001). CONCLUSIONS Greater anterior chamber diameters were associated with flatter corneas and, conversely, smaller anterior chamber diameters with steeper corneas. The growth patterns of the anterior segment may be determinants of corneal power.

PURPOSE To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. METHODS All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. RESULTS The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P < 0.001) and nuclear lens opacity grade (β = -0.42; P < 0.001), followed by axial length (β = -0.35; P < 0.001). They were lowest for corneal refractive power (β = -0.08; P = 0.001) and anterior chamber depth (β = -0.05; P = 0.04). In multivariate analysis, refractive error was significantly (P < 0.001) associated with shorter axial length (β = -1.26), lower refractive lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. CONCLUSIONS Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.