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Behboudi H, Rajavi Z, Sabbaghi H, Katibeh M, Kheiri B, Yaseri M, Moradian S, Alizadeh Y, Ahmadieh H, Pakbin M, Bouyeh A, Moradi A. Prevalence of refractive errors in population aged 50 years and over: The Gilan eye study. Eur J Ophthalmol 2024; 34:449-460. [PMID: 37349990 DOI: 10.1177/11206721231184544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
PURPOSE To describe the prevalence of refractive error (RE) and its association with other environmental and health factors among population aged ≥50 years who lived in Gilan, Iran in 2014. METHODS In this population-based cross-sectional study, 3281 individuals aged ≥50 years living in Gilan for at least 6 months were enrolled. The prevalence of different types of REs including myopia (spherical equivalent (SE)≤-0.50D), high myopia (SE ≤ -6.00D), hyperopia (SE≥ + 0.50D), high hyperopia (SE≥ + 3.00D), astigmatism (cylinder < -0.50D) and high astigmatism (cylinder < -2.25D) were determined. Anisometropia was defined as the SE difference of ≥1.00D between the two eyes. Associated factors including age, body mass index (BMI) and education were also studied. RESULTS 2587 eligible individuals (58% female subjects) with the mean age of 62.6 ± 8.8 years participated (87.6% response rate). The prevalence of myopia, hyperopia and astigmatism was 19.2%, 48.6% and 57.4%, respectively. 3.6% high hyperopia, 0.5% high myopia and 4.5% high astigmatism were identified. The positive simultaneous effects3 of older age (Odds Ratio (OR) = 3.14), nuclear (OR = 1.71) and posterior subcapsular (OR = 1.61) cataracts as well as the negative effects of higher levels of education (OR = 0.28) were obtained on myopia. Higher BMI was found as a risk factor for hyperopia (OR = 1.67), while older patients were less likely to be hyperopic (OR = 0.31). CONCLUSION Higher incidence of myopia and astigmatism was found in patients aged over 70 years. It was also found that patients at older ages who suffered with cataracts were at a higher risk of myopia, while elderly people with greater BMI were at a higher risk of hyperopia.
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Affiliation(s)
- Hassan Behboudi
- Department of Ophthalmology, Guilan University of Medical Sciences, Rasht, Iran
| | - Zhale Rajavi
- Ophthalmic Epidemiology Research Centre, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Negah Aref Ophthalmic Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Ophthalmology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamideh Sabbaghi
- Ophthalmic Epidemiology Research Centre, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marzieh Katibeh
- Department of Public Health, Centre for Global Health, Aarhus University, Aarhus, Denmark
| | - Bahareh Kheiri
- Ophthalmic Research Centre, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Yaseri
- Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran
| | - Siamak Moradian
- Ophthalmic Research Centre, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yousef Alizadeh
- Department of Ophthalmology, Guilan University of Medical Sciences, Rasht, Iran
| | - Hamid Ahmadieh
- Ophthalmic Research Centre, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mojgan Pakbin
- Noor Ophthalmology Research Centre, Noor Eye Hospital, Tehran, Iran
- Translational Ophthalmology Research Centre, Tehran University of Medical Sciences, Tehran, Iran
| | - Aria Bouyeh
- Rehabilitation Research Centre, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Amir Moradi
- Department of Ophthalmology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Hashemi H, Khabazkhoob M, Lança C, Emamian MH, Fotouhi A. Prevalence of anisometropia and its associated factors in school-age children. Strabismus 2024; 32:1-10. [PMID: 38230509 DOI: 10.1080/09273972.2023.2293883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
PURPOSE To determine the prevalence of anisometropia and the associated demographic and biometric risk factors in children. METHODS This cross-sectional study was conducted on the elementary school children of Shahroud, east of Iran, in 2015. All rural students were recruited, while multistage cluster sampling was used to select the students in urban areas. All children underwent optometric examinations including the measurement of uncorrected and corrected visual acuity, autorefraction, and subjective refraction with cycloplegia. Biometric components were measured using the Allegro Biograph. Myopia and hyperopia were defined as a spherical equivalent ≤-0.5 and ≥ +2.00 diopter, respectively. Students with a history of ocular trauma or lack of cycloplegic refraction at least in one eye were excluded from the study. RESULTS Of 6624 selected children, 5620 participated in the study. After applying the exclusion criteria, the data of 5357 students (boys: 52.8%, n = 2834) were analyzed. The mean age of the subjects was 9.2 ± 1.7 years (range: 6-12 years). The prevalence of anisometropia ≥ 1 D was 1.1% (95% CI: 0.8 to 1.4) in all children, 1.0% (95% CI: 0.7-1.3) in boys, 1.3% (95% CI: 0.8-1.7) in girls, 1.1% (95% CI: 0.8-1.4) in urban children, and 1.4% (95% CI: 0.5-2.3) in rural children. The prevalence of anisometropia was 8.8% (95% CI: 5.3-12.2) in myopic and 5.7% (95% CI: 2.8-8.5) in hyperopic children. Axial length asymmetry (OR = 40.9; 95%CI: 10.2-164.1), myopia (OR = 17.9; 95% CI: 9.4-33.9), and hyperopia (OR = 10.1; 95% CI: (5.1-19.7) were associated with anisometropia in multiple logistic regression model. More anisometropia was associated with more severe amblyopia. The odds of amblyopia (OR = 82.3: 38.2-177-3) and strabismus (OR = 17.6: 5.5-56.4) were significantly higher in anisometropic children. The prevalence of amblyopia was 21.7% in children with myopic anisometropia ≥ 3D, 66.7% in children with hyperopic anisometropia ≥ 3D, and 100% in cases with antimetropia ≥ 3D. CONCLUSION The prevalence of anisometropia was low in Iranian school children. However, a high percentage of anisometropic students had amblyopia and strabismus. Axial length was the most important biometric component associated with anisometropia.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Carla Lança
- Escola Superior de Tecnologia da Saúde de Lisboa (ESTeSL), Instituto Politécnico de Lisboa, Lisboa, Portugal
- Comprehensive Health Research Center (CHRC), Escola Nacional de Saúde Pública, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Mohammad Hassan Emamian
- Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Zhou Y, Zhang XF, Chen XJ, Wang M, Cai JR, Xiong YJ, Song Y, Sun ZM. Prevalence of anisometropia and influencing factors among school-age children in Nantong, China: a cross-sectional study. Front Public Health 2023; 11:1190285. [PMID: 37397717 PMCID: PMC10307961 DOI: 10.3389/fpubh.2023.1190285] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Objective To investigate the prevalence of anisometropia and associated parameters among school-aged children in Nantong, China. Methods This school-based, cross-sectional study examined students from primary schools, junior high schools, and senior high schools in an urban area of Nantong, China. Univariate and multivariate logistic regression analyses were used to investigate the specific correlations between anisometropia and related parameters. Non-cycloplegic autorefraction was assessed for each student. Anisometropia was defined as the spherical equivalent refraction (SE) difference ≥ 1.0 D between eyes. Results A total of 9,501 participants were validated for analyses, of which 53.2% (n = 5,054) were male, and 46.8% (n = 4,447) were female. The mean of age was 13.32 ± 3.49 years, ranging from 7-19 years. The overall prevalence of anisometropia was 25.6%. Factors such as myopia, scoliosis screening positive, hyperopia, female sex, older age, and higher weight had a significantly higher risk of anisometropia (p < 0.05). Conclusion There was a high prevalence of anisometropia in school-age children. Some physical examination parameters are closely related to children's anisometropia, especially myopia and scoliosis. Preventing myopia and controlling its progression may be the most important ways to reduce the prevalence of anisometropia. Correcting scoliosis may be an important factor in controlling the prevalence of anisometropia, and maintaining good reading and writing posture may be helpful in controlling the prevalence of anisometropia.
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Affiliation(s)
- Yue Zhou
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Xiao Fang Zhang
- Department of Nantong Fifth People’s Hospital, Nantong, Jiangsu, China
| | - Xiao Juan Chen
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Min Wang
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Jian Ru Cai
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Yao Jia Xiong
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Yu Song
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Zhi Min Sun
- Department of Ophthalmology, Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
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Vincent SJ, Collins MJ, Read SA, Carney LG. Myopic anisometropia: ocular characteristics and aetiological considerations. Clin Exp Optom 2021; 97:291-307. [DOI: 10.1111/cxo.12171] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 02/14/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia,
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia,
| | - Scott A Read
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia,
| | - Leo G Carney
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia,
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Eyes of Aniso-Axial Length Individuals Share Generally Similar Corneal Biometrics with Normal Eyes in Cataract Population. J Ophthalmol 2020; 2020:4760978. [PMID: 33178451 PMCID: PMC7648247 DOI: 10.1155/2020/4760978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/01/2020] [Accepted: 10/14/2020] [Indexed: 11/17/2022] Open
Abstract
AIMS To determine the characteristics of corneal biometrics in eyes from aniso-axial length cataract patients compared with eyes from non-aniso-axial length individuals. METHODS This is a retrospective case series. Cataract patients with preoperative binocular measurements were recruited. A binocular axial difference of ≥1 mm was considered to indicate aniso-axial length. The anterior segmental biometrics were measured using Pentacam HR (Oculus, Wetzlar, Germany) and IOLMaster 500 (Carl Zeiss Meditec, Jena, Germany). Comparisons of biometrics were made among 4 eye conditions: the longer eyes from aniso-axial length patients, the shorter eyes from aniso-axial length patients, the longer eyes from non-aniso-axial length patients, and the shorter eyes from non-aniso-axial length patients. The aniso-axial length eyes were also stratified into 8 subgroups with axial length (AL) increments of 1 mm, and the biometrics of the subgroups were compared. RESULTS There was smaller anterior corneal astigmatism in the shorter aniso-axial length group than those in the longer aniso-axial length group (1.01 ± 0.70 D vs 1.12 ± 0.76 D, P=0.031). The longer aniso-axial length eyes had greater anterior corneal steep curvature (44.13 ± 1.69 D vs 43.87 ± 1.69 D, P=0.009) and anterior corneal astigmatism (1.12 ± 0.76 D vs 1.02 ± 0.69 D, P=0.023) compared with longer non-aniso-axial length subjects. Other corneal biometrics were similar between the aniso-axial length eyes and the non-aniso-axial length eyes. In the longer aniso-axial length group, the posterior corneal aberrations of eyes in the ≥5 mm subgroups were greater than those in the <5 mm subgroups (0.879 ± 0.183 μm vs 0.768 ± 0.178 μm for total aberrations, P < 0.001; 0.228 ± 0.086 μm vs 0.196 ± 0.043 μm for high-order aberrations, P=0.036; 0.847 ± 0.173 μm vs 0.741 ± 0.179 μm for low-order aberrations, P=0.001). CONCLUSION Eyes of aniso-axial length individuals share generally similar corneal biometrics with normal eyes in cataract population. Anterior corneal astigmatism of the longer eyes from the aniso-axial length cataract patients was higher than that of the longer eyes from the non-aniso-axial length individuals. Total posterior corneal aberrations of the longer aniso-axial length eyes increased when the binocular axial difference was over 5 mm.
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Pärssinen O, Kauppinen M, Halekoh U, Kaprio J, Rantanen T. Heredity of interocular similarities in components of refraction: a population-based twin study among 66- to 79-year-old female twins. Acta Ophthalmol 2019; 97:603-607. [PMID: 30702215 DOI: 10.1111/aos.14033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/02/2019] [Indexed: 01/25/2023]
Abstract
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 anisometropic values. The cut-offs for grading as isometropic were AnisoSR < 0.75 D, AnisoAST < 0.5 D, AnisoSE < 1.0 D, AnisoCR < 0.5 D, AnisoCAST < 0.50 D, AnisoACD < 0.1 mm and AniosAL < 0.1 mm. Genetic influences on these traits were investigated by comparing the prevalence of isometropic and anisometropic differences between the MZ and DZ pairs in the Aniso variables and the interrelationships between the Aniso variables. RESULTS When the Aniso variables were treated as continuous, no significant differences were found between the MZ and DZ subjects. When the proportions of isometropic intratwinpair interocular differences in the Aniso variables in the MZ and DZ cotwins were compared, the prevalences (MZ/DZ) were AnisoSR: 68%/60%; AnisoAST: 66%/57%; AnisoSE: 87%/68%; AnisoCR: 83%/78%; AnisoCAST: 69%/35%; AnisoACD: 77%/63%; and AnisoAL: 76%/60%. The differences were statistically significant for Aniso SE (p = 0.035, Fisher's exact test) and CAST (p = 0.007). The greater homogeneity in the interocular differences between the MZ sisters supports the assumption that isometropia of different elements of refraction is genetically influenced and tending to continue up to older ages. In cases where AnisoSE was <1.0 D, higher CR in one eye was associated with shorter AL (r = -0.398, p < 0.001), thereby contributing to emmetropization, irrespective of zygosity. In the cases of AnisoSE ≥1 D, no similar influence on emmetropization was observed. The difference between sisters in AnisoSE was associated with the intratwinpair difference in Aniso AL, but not with the intratwinpair differences in AnisoCR, irrespective of zygosity. CONCLUSION The higher prevalence of similarities in isometropia of the spherical equivalent and corneal astigmatism between the MZ pairs compared to DZ pairs is consistent with the view that genetic influences on the refractive elements of the eye, tending to isometropia, continue into older age. The interrelation between CR and AL tends to maintain isometropia of SE irrespective of zygosity.
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Affiliation(s)
- Olavi Pärssinen
- Department of Ophthalmology Central Hospital of Central Finland Jyväskylä Finland
- Gerontology Research Center and Faculty of Sport and Health Sciences University of Jyvaskyla Jyväskylä Finland
| | - Markku Kauppinen
- Gerontology Research Center and Faculty of Sport and Health Sciences University of Jyvaskyla Jyväskylä Finland
| | - Ulrich Halekoh
- Department of Public Health University of Southern Denmark Odense Denmark
| | - Jaakko Kaprio
- Department of Public Health University of Helsinki Helsinki Finland
- Institute for Molecular Medicine FIMM University of Helsinki Helsinki Finland
- Department of Health National Institute for Health and Welfare Helsinki Finland
| | - Taina Rantanen
- Gerontology Research Center and Faculty of Sport and Health Sciences University of Jyvaskyla Jyväskylä Finland
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Wang X, Pan J, Zhang Y, Lan Y, Zuo J, Jiang Z. Prevalence and Associations of Myopic Anisometropia in Chinese Adults. Eye Contact Lens 2019; 46:147-153. [PMID: 31211720 DOI: 10.1097/icl.0000000000000627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the prevalence and associations of myopic anisometropia in Chinese adults. METHODS A total of 3,791 Chinese refractive surgery candidates with myopia (25.15±7.09 years old, Mean±SD) were recruited. All eyes underwent a standardized ophthalmological examination. Associations between myopic anisometropia and age, gender, spherical ametropia, astigmatism, and axial length (AL) were analyzed by means of the chi-squared test, nonparametric Kruskal-Wallis or Mann-Whitney test, binomial logistic regression analyses, and multivariate logistic regression analysis. RESULTS The mean myopic anisometropic level was 0.96 D and prevalence of myopic anisometropia was 29.62% (defined as myopic anisometropia ≥1.00 D). The prevalence and severity of myopic anisometropia increased with age, larger interocular AL difference, and higher cylindrical power (all P<0.001). Myopic anisometropia showed a U-shaped correlation with spherical equivalent (SE) refractive error and V-shaped correlations with AL, J0 and J45. Myopic anisometropia was most strongly associated with interocular AL difference (P<0.001). CONCLUSIONS Compared with previous reports, this study revealed an even higher prevalence of myopic anisometropia and showed a U-shaped correlation with SE and a V-shaped correlation with AL. These results indicate that the formation of myopic anisometropia could be related to neural control in the binocular AL growth balance. Further study is needed to clarify this presumption.
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Affiliation(s)
- Xianglong Wang
- Department of Ophthalmology (X.W., J.P., Y.Z., Z.J.), The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Refractive Surgery, School of Optometry and Ophthalmology and Eye Hospital (X.W., J.P., Y.L., J.Z., Z.J.), Wenzhou Medical University, Wenzhou, Zhejiang, China; and Department of Ophthalmology (X.W.), The Affiliated Yueqing Hospital of Wenzhou Medical University, Wenzhou, China
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Pärssinen O, Kauppinen M, Kaprio J, Rantanen T. Anisometropia of ocular refractive and biometric measures among 66- to 79-year-old female twins. Acta Ophthalmol 2016; 94:768-774. [PMID: 27273930 DOI: 10.1111/aos.13125] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022]
Abstract
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 excluded, but the grade of nuclear opacity was not recorded. The associations between the absolute values of AnisoSR, AnisoAST and AnisoSE with SR, AST, SE, corneal refractive power (CR), corneal astigmatism (CAST), anterior chamber depth (ACD) and axial length (AL) and with their interocular differences were calculated. When calculating the interdependencies of the differences, the real and absolute differences between the right and left eye were used. RESULTS Means ± standard deviations for AnisoSR, AnisoAST and AnisoSE were 0.67 ± 0.92 D, 0.42 ± 0.41 D and 0.65 ± 0.71 D, respectively. AnisoSR, AnisoAST and AnisoSE >1.0 D were present in 14.7%, 4.2% and 17.7% of cases, respectively. Anisometropia of spherical refraction (AnisoSR), AnisoAST and AnisoSE were higher the more negative the values of SR or SE. Hyperopic ametropia did not increase these anisometropia values. The correlations of AnisoSR and AnisoSE with the absolute values of interocular differences in CR and AL were non-significant. Using the real values of the interocular differences, the respective correlations were significant. The correlation between the real interocular differences in CR and AL was negative (r = -0.258, p < 0.001). Thus, the combined effect of the real interocular differences in CR and AL was a decrease in AnisoSR and AnisoSE (emmetropization). CONCLUSION Higher AnisoSR and AnisoSE were associated with more myopic refraction and longer AL. Higher AnisoAST was associated with more negative SR and higher AST and CAST. The negative correlation between real interocular differences in CR and AL indicated their influence of emmetropization in AnisoSR and AnisoSE.
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Affiliation(s)
- Olavi Pärssinen
- Department of Ophthalmology; Central Hospital of Central Finland; Jyväskylä Finland
- Gerontology Research Center and Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
| | - Markku Kauppinen
- Gerontology Research Center and Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
| | - Jaakko Kaprio
- Gerontology Research Center and Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
- Department of Public Health; University of Helsinki; Helsinki Finland
- Institute for Molecular Medicine; University of Helsinki; Helsinki Finland
- Department of Health; National Institute for Health and Welfare; Helsinki Finland
| | - Taina Rantanen
- Gerontology Research Center and Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
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Abstract
Animals with front facing eyes benefit from a substantial overlap in the visual fields of each eye, and devote specialized brain processes to using the horizontal spatial disparities produced as a result of viewing the same object with two laterally placed eyes, to derived depth or 3-D stereo information. This provides the advantage to break the camouflage of objects in front of similarly textured background and improves hand eye coordination for grasping objects close at hand. It is widely thought that about 5% of the population have a lazy eye and lack stereo vision, so it is often supposed that most of the population (95%) have good stereo abilities. We show that this is not the case; 68% have good to excellent stereo (the haves) and 32% have moderate to poor stereo (the have-nots). Why so many people lack good 3-D stereo vision is unclear but it is likely to be neural and reversible.
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Affiliation(s)
- Robert F Hess
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Canada
| | - Long To
- Centre for Intelligent Machines, McGill University, Montreal, Canada
| | - Jiawei Zhou
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Canada
| | - Guangyu Wang
- Centre for Intelligent Machines, McGill University, Montreal, Canada
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