The Relationship between Progression in Axial Length/Corneal Radius of Curvature Ratio and Spherical Equivalent Refractive Error in Myopia

2018 ◽  
Vol 95 (10) ◽  
pp. 921-929 ◽  
Author(s):  
Monica Jong ◽  
Padmaja Sankaridurg ◽  
Thomas John Naduvilath ◽  
Wayne Li ◽  
Mingguang He
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Radius Of Curvature ◽  
Spherical Equivalent ◽  
Curvature Ratio ◽  
Corneal Radius ◽  
The Relationship

scholarly journals The Role of Axial Length-Corneal Radius of Curvature Ratio in Refractive State Categorization in a Nigerian Population

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Eghosasere Iyamu ◽  
Joy Iyamu ◽  
Christian Izuchukwu Obiakor
Keyword(s):  
Axial Length ◽  
Inverse Correlation ◽  
Radius Of Curvature ◽  
Spherical Equivalent ◽  
Refractive State ◽  
Spherical Equivalent Refraction ◽  
Nigerian Population ◽  
Corneal Radius ◽  
The Mean

The aim of this study was to investigate the association of axial length (AL)/corneal radius of curvature (CRC) ratio (AL/CRC) with spherical equivalent refractive state (SER) in young adults. A total of seventy () subjects consisting of 31 males and 39 females participated in this study. Subjects were categorized into emmetropia, hyperopia and myopia using the spherical equivalent refraction. The axial length was measured with I-2100 A-Scan ultrasonography/Biometer (CIMA Technology, USA), the corneal radius of curvature with Bausch & Lomb H-135A (Bausch & Lomb Corp., USA), and the refractive state by static retinoscopy and subjective refraction. The mean AL, CRC and AL/CRC ratio of all subjects were 23.74 ± 0.70 mm, 7.84 ± 0.19 mm, and 3.03 ± 0.14, respectively. Myopes had significantly longer AL, steeper CRC and higher AL/CRC ratio than the emmetropes and hyperopes. There was statistically significant inverse correlation between AL and CRC (, ), SER (, ), and between SER and AL/CRC (, ). A significant positive correlation was found between CRC and SER (, ). The categorization of the refractive state of an individual is better done by using the AL/CRC ratio index.

Axial Length/Corneal Radius of Curvature Ratio Assessment of Posterior Sclera Reinforcement for Pathologic Myopia

2017 ◽  
Vol 239 (2-3) ◽  
pp. 128-132 ◽  
Author(s):  
Huiling Hu ◽  
Guangyu Zhao ◽  
Ruifeng Wu ◽  
Huahong Zhong ◽  
Min Fang ◽  
...  
Keyword(s):  
Axial Length ◽  
Pathologic Myopia ◽  
Radius Of Curvature ◽  
Curvature Ratio ◽  
Corneal Radius

scholarly journals Axial Length/Corneal Radius of Curvature Ratio and Myopia in 3-Year-Old Children

2016 ◽  
Vol 5 (1) ◽  
pp. 5 ◽  
Author(s):  
Valencia Hui Xian Foo ◽  
Pavan Kumar Verkicharla ◽  
Mohammad Kamran Ikram ◽  
Sharon Yu Lin Chua ◽  
Shirong Cai ◽  
...  
Keyword(s):  
Axial Length ◽  
Radius Of Curvature ◽  
Curvature Ratio ◽  
Corneal Radius

scholarly journals Evaluation of the Relationships between Corneal Parameters, Ocular Biometry, and Myopia Magnitude

2021 ◽  
Vol 50 (10) ◽  
pp. 3077-3084
Author(s):  
Mohd Izzuddin Hairol ◽  
Norlaili Arif ◽  
Pui Theng Yong ◽  
Mariah Asem Shehadeh Saleh Ali ◽  
Nik Nor Adlina Nik Idris ◽  
...  
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Radius Of Curvature ◽  
Corneal Curvature ◽  
Ocular Biometry ◽  
Corneal Asphericity ◽  
Corneal Radius ◽  
The Difference ◽  
The Relationship

Axial length of the eye correlates with the magnitude of myopia. However, there are conflicting reports on the relationship between certain corneal parameters with myopia magnitude. The objective of this study was to compare ocular biometry and corneal parameters between emmetropic and myopic groups. Participants (n=127) were categorized as emmetropia (spherical equivalent, SE, ±0.50D), low myopia (-0.75D≤SE<-6.00D) and high myopia (SE≥-6.00D). The difference in axial length, anterior chamber depth, and vitreous chamber depth between emmetrope, low myope, and high myope were highly significant (one-way ANOVA, all p<0.001) with significant correlations between SE and all these parameters (simple regressions, all p<0.001). However, central corneal thickness, corneal radius of curvature, and corneal asphericity between these groups, and the correlations between the ocular parameters with SE were not significantly different (all p>0.05). Corneal curvature correlated significantly with axial length (p=0.001) but not with myopia magnitude (p=0.91). Rather than myopia magnitude, axial length appears to be more sensitive to detect changes in corneal curvature in myopes. In conclusion, myopic patients’ axial length should be carefully considered for interventions that involve the cornea, such as orthokeratology and refractive surgery.

scholarly journals Study of Cataract in Relation to Axial Length and Refractivity of the Eye

1970 ◽  
Vol 12 (3) ◽  
pp. 130-134
Author(s):  
Surabhi Sharma ◽  
Satyaswarup Tripathy ◽  
Syed Ali Raza Rizvi
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Age Groups ◽  
Nuclear Cataract ◽  
Spherical Equivalent ◽  
Posterior Subcapsular Cataract ◽  
Age Related ◽  
Different Types ◽  
The Relationship ◽  
Axial Myopia

Aim: To ascertain the association between different types and densities of age-related cataract with axial length and refractive state of the eye.Methods: This prospective observational institute-based study enrolled 462 eyes of 450 patients aged 40 years or older. Eyes were classified as myopic (axial length, >25 mm), emmetropic (axial length, 21-25 mm), and hypermetropic (axial length, <21 mm). Refractive error was defined as myopia (spherical equivalent, <-0.5 D) and hypermetropia (spherical equivalent, >+0.5 D). Cataract was categorised as nuclear, cortical, or posterior subcapsular. Nuclear density was measured based on the Emery and Little Classification after slit-lamp biomicroscopy. Student t test for unpaired samples and Fisher and Yates tables were used to analyse statistical significance.Results: Emmetropia was the most common condition (417 eyes). The most common cataract combination was nuclear with posterior subcapsular (n = 198; 44%). In the axial myopia group, nuclear cataract was thecommonest type, alone or in combination with other types (n = 33; 100%). Most eyes had refractive error of 0 to -5 D. The grade of nuclear cataract increased with increasing age (n = 48 for grade IV nuclear cataract in the 70 to 79 years age group). In all age groups, a higher grade of nuclear sclerosis was significantly associated with axial length (t = 2.2; p < 0.05). The relationship was also significant for posterior subcapsular cataract (t = 2.7; p < 0.05).Conclusions: Nuclear cataract leads to a myopic shift in refraction. In otherwise healthy eyes, there is a gradual hypermetropic shift. The prevalence and grade of nuclear cataract increases with age. Longer axial length is associated with a higher grade of nuclear and posterior subcapsular cataract.

Axial length/corneal radius of curvature ratio and refractive status in an adult Nigerian population

2017 ◽  
Vol 20 (10) ◽  
pp. 1328 ◽  
Author(s):  
SA Badmus ◽  
AI Ajaiyeoba ◽  
BO Adegbehingbe ◽  
OH Onakpoya ◽  
AO Adeoye
Keyword(s):  
Axial Length ◽  
Radius Of Curvature ◽  
Curvature Ratio ◽  
Refractive Status ◽  
Nigerian Population ◽  
Corneal Radius

scholarly journals The Correlation of Cycloplegic Refraction with Corneal Radius of Curvature-Adjusted Axial Length in Chinese Preschoolers

2021 ◽  
Author(s):  
Xiao-hong Zhou ◽  
Yian Li ◽  
Wei Wang ◽  
Chen-hao Yang
Keyword(s):  
Axial Length ◽  
Chinese Children ◽  
Radius Of Curvature ◽  
Refractive Errors ◽  
Spherical Equivalent ◽  
Spherical Equivalent Refraction ◽  
Curvature Coefficient ◽  
Corneal Radius ◽  
The Mean ◽  
And Gender

Abstract Background: In order to master the refractive status and detect severe refractive errors quickly and effectively, this study aimed to investigate the association of axial length after adjusting for corneal radius of curvature with refraction in a group of Chinese preschoolers. Methods: Retrospective review of 716 Chinese children aged from 3 to 6 years, who underwent cycloplegic optometry with 1% atropine eye gel in the ophthalmology department of Children’s Hospital of Fudan University, National Children’s Medical Center in Shanghai. Meanwhile axial length, corneal radius of curvature and cycloplegic autorefraction were obtained and axial length/corneal radius of curvature (AL/CR) ratio was calculated. The correlations of spherical equivalent refraction (SER) with axial length, corneal radius of curvature, AL/CR ratio and corneal radius of curvature-adjusted axial length were analyzed. Results: Only data from the right eye were included in this analysis. Among 716 eyes of 716 Chinese preschoolers, the mean (±SD) SER was 2.28±2.41 diopters (D), of which hyperopia, emmetropia, myopia were 84.64%, 8.54%, 6.84%, respectively. The mean(±SD) axial length, corneal radius of curvature and AL/CR ratio were 21.89±1.01mm, 7.76±0.27 mm, and 2.82±0.13, respectively. The SER was highly negative correlated with both axial length (coefficient –0.722) and AL/CR ratio (coefficient-0.814), and weakly correlated with corneal radius of curvature (coefficient 0.090) and gender(coefficient 0.093). Axial length was weakly correlated with age and gender(coefficient 0.232 and 0.268, respectively), but moderately correlated with corneal radius of curvature (coefficient 0.424). After adjusting for corneal radius of curvature, the correlation coefficient between SER and axial length significantly increased to-0.918. Conclusion: In the samples of 716 3-to 6-year-old Chinese children, axial length was moderately correlated with corneal radius of curvature. After adjusting for corneal radius of curvature, refraction was closely correlated with axial length than axial length alone and AL/CR ratio. Therefore, corneal radius of curvature-adjusted axial length might be a useful tool for pediatric ophthalmologists to detect refractive errors. Key Words: spherical equivalent refraction; corneal radius of curvature; adjusted; axial length; preschoolers.

scholarly journals Correlation of refractive error with axial length and corneal topography

2016 ◽  
Vol 15 (1) ◽  
pp. 25-33
Author(s):  
Surabhi Ruia ◽  
Poonam Kishore ◽  
Vinita Singh ◽  
Nitin Chaudhary
Keyword(s):  
Negative Correlation ◽  
Refractive Error ◽  
Axial Length ◽  
Corneal Topography ◽  
Radius Of Curvature ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Study Materials ◽  
Group 5 ◽  
Group 2

Purpose: To collect and analyze normative data about corneal topography and axial length in various refractive errors in Indian population.Design: Cross-sectional observational study. Materials and Method: Three hundred eyes (150 patients) of age group 12-35 yrs were arranged in 5 groups according to refractive status; Group 1 (n=44): myopia of SphericalEquivalent (SE) > 6 D; Group 2 (n=67): myopia of SE >0.5 D to 6 D; Group 3 (n=88): nearly emmetropic of SE -0.5 D to +0.5 D; Group 4 (n=59): hypermetropia of SE >0.5 to 6 D; Group 5 (n=42): hypermetropia of SE > 6 D. Axial length(AL), central radius of curvature of cornea (CR), central power of cornea (CK) , Al/CR ratio for each group were documented . Correlation with SE and among each other was studied. Results: Mean AL (in mm) of myopic patients (n=111) was 24.23 ± 1.34, emmetropic (n=88) 22.62 ± 0.94 and hypermetropics (n=101) 20.73 ±0.94. Mean CR (in mm) of myopic patients was 7.55 ± 0.35, emmetropics was 7.70 ±0.32, and hypermetropes was 7.99 ±0.35. Mean CK (in D) of myopics was 44.86±2.59, emmetropes was 43.91±1.76, and hypermetropes was 42.32±1.89. Mean AL/CR ratio of myopics was 3.22 ± 0.29, emmetropics 2.94± 0.07, and hypermetropics 2.60 ± 0.19. AL was negatively correlated with SE(r=-0.91, p<0.0001) and positively with AL/CR(r=0.88, p<0.0001) and CK (r=0.36, p<0.0001). CR was negatively correlated with AL/CR (r=-0.74, p<0.0001) while positively correlated with SE (r=0.62, p<0.0001). CK showed positive correlation with AL/CR (r=0.75, p<0.0001) while negative correlation with SE (r=-0.61, p<0.0001). AL/CR was negatively correlated withSE(r=-0.95, p<0.0001). Conclusion: This study showed a negative correlation between axial length and refractive error and between AL/CR ratio and refractive error with stronger inverse relationship in hypermetropes than myopes. There was a positive correlation of CR with SE with a weaker direct relationship in myopes than hypermetropes. 

scholarly journals A calculator proposal for estimating refractive error after 3 years using the onset biometric values in primary school children: a cohort study

2021 ◽  
Author(s):  
Feride Tuncer Orhan ◽  
Haluk Huseyin Gürsoy
Keyword(s):  
Primary School ◽  
Anterior Chamber ◽  
Refractive Error ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
Primary School Children ◽  
Optical Parameters ◽  
Spherical Equivalent ◽  
Final Data ◽  
The Mean

Aim To evaluate consecutive measurements of the biometric parameters, age, and refraction error in a Turkish population at primary school age. Materials and Methods A total of 197 children aged between 7-12 years were included. The data of three consecutive measurements of children, who were examined at least once a year for three years using both cycloplegic auto-refractometry and optical biometry, were used in this retrospective study. Spherical equivalent <-0.50D was considered to be myopic; >+0.75D was considered to be hypermetropic. Age, gender, body mass index, spherical equivalent, axial length, anterior chamber depth, central corneal thickness, keratometry, and lens thickness were analyzed. The onset data obtained in 2013 whereas, the final data were from 2015. Logistic and Cox regression analyses were performed (p<0.05). Results The mean of the onset and the final spherical equivalents were 0.19D (0.56), and 0.08D (0.80), respectively. The myopia prevalence was increased among refractive errors in observation periods (univariable analysis p=0.029; multivariable analysis p=0.017). The onset axial length (HR:4.55, 95%CI:2.87-7.24, p<0.001), keratometry (HR:2.04, 95%CI:1.55-2.67, p<0.001) and age (HR:0.73, 95%CI: 0.57-0.92, p=0.009) correlated myopia progression. To calculate the estimated spherical equivalent, the onset data were included in the logistic regression model. The onset data of spherical equivalent (β=0.916, p<0.001), axial length (β=-0.451, p<0.001), anterior chamber depth (β=0.430, p=0.005) and keratometry (β=-0.172, p<0.001) were found to be significantly associated with the mean SE at the final data. Conclusions To calculate the estimated spherical equivalent following three years, an equation was proposed. The estimated refractive error of children can be calculated by using the proposed equation with the associated onset optical parameters.

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