Role of the Axial Length/Corneal Radius Ratio in Determining the Refractive State of the Eye

1994 ◽  
Vol 71 (9) ◽  
pp. 573-579 ◽  
Author(s):  
THEODORE GROSVENOR ◽  
ROLENE SCOTT
Keyword(s):  
Axial Length ◽  
Radius Ratio ◽  
Refractive State ◽  
Corneal Radius

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.

scholarly journals Axial Length/Corneal Radius Ratio: Association with Refractive State and Role on Myopia Detection Combined with Visual Acuity in Chinese Schoolchildren

PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0111766 ◽  
Author(s):  
Xiangui He ◽  
Haidong Zou ◽  
Lina Lu ◽  
Rong Zhao ◽  
Huijuan Zhao ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Axial Length ◽  
Radius Ratio ◽  
Refractive State ◽  
Corneal Radius

Lens Power, Axial Length-to-Corneal Radius Ratio, and Association with Diabetic Retinopathy in the Adult Population with Type 2 Diabetes

Ophthalmology ◽  
2017 ◽  
Vol 124 (3) ◽  
pp. 326-335 ◽  
Author(s):  
Jiangnan He ◽  
Xian Xu ◽  
Jianfeng Zhu ◽  
Bijun Zhu ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Diabetic Retinopathy ◽  
Axial Length ◽  
Adult Population ◽  
Radius Ratio ◽  
Corneal Radius ◽  
Lens Power

scholarly journals Impact of the anterior-posterior corneal radius ratio on intraocular lens power calculation errors

2018 ◽  
Vol Volume 12 ◽  
pp. 1549-1558 ◽  
Author(s):  
Asato Hasegawa ◽  
Takashi Kojima ◽  
Mana Yamamoto ◽  
Yukihito Kato ◽  
Akeno Tamaoki ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Radius Ratio ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Intraocular Lens Power ◽  
Corneal Radius ◽  
Lens Power ◽  
Lens Power Calculation ◽  
Anterior Posterior

Evaluation of the B/F Ratio Distribution of Cataract Patients Without Corneal Abnormalities and Its Effect on Ocular Parameters

2021 ◽  
Vol 44 (4) ◽  
pp. E46-54
Author(s):  
Michael Deng ◽  
Lina Lan ◽  
Tianhui Chen ◽  
Min Zhang ◽  
Jiahui Chen ◽  
...  
Keyword(s):  
Axial Length ◽  
Central Corneal Thickness ◽  
Spherical Aberration ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Curvature Radius ◽  
Multivariate Linear Regression Analysis ◽  
Corneal Surface ◽  
Ratio Distribution ◽  
Corneal Radius

Purpose: To evaluate the distribution of the posterior-anterior corneal radius ratio (B/F ratio; posterior corneal radius/anterior corneal radius) in patients without corneal abnormalities, and to investigate which parameters affect this ratio. Methods: Five thousand eyes from 5,000 patients who underwent cataract surgery were recruited to this study. We explored the linear relationship between B/F ratio and 13 variables using Principal Component-Multivariate Linear Regression Analysis. Results: The B/F ratio was negatively correlated with the difference between simulated keratometry (SimK) and true net power (TNP), central corneal thickness, spherical aberration (SA), and posterior corneal astigmatism and positively correlated with posterior corneal radius, corneal posterior surface, axial length (AL) and anterior corneal radius. Several variables (central corneal thickness, difference between SimK and TNP and asphericity coefficient (Q-value) of the posterior corneal surface) had the highest loading on the final score. B/F ratio reflects the refractive state and anatomical structure of the cornea: thus, higher B/F ratios were associated with larger posterior corneal surface curvature radius, longer axial length, thinner central corneal thickness, lower high order aberrations of the cornea and SA, and the numerical difference between simK and TNP gradually reduced. In clinical practice, for patients with lower B/F ratio, special care should be taken in the choice of system used for intraocular lens (IOL) measurements.

scholarly journals Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles

2018 ◽  
Vol 3 (1) ◽  
pp. e000204 ◽  
Author(s):  
Kin Wan ◽  
Sin Wan Cheung ◽  
James S Wolffsohn ◽  
Janis B Orr ◽  
Pauline Cho
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Significant Negative Correlation ◽  
Biomechanical Properties ◽  
Corneal Hysteresis ◽  
Axial Elongation ◽  
Single Vision ◽  
Length Data ◽  
Corneal Biomechanical Properties

ObjectiveTo determine the characteristics of children who were likely to progress rapidly and gain the greatest benefit from orthokeratology (ortho-k) treatment.Methods and analysisThe files of 113 children who participated in two myopia control studies and wore either ortho-k lenses (n=62) or single-vision spectacles (SVS) (n=51) were reviewed. Baseline cycloplegic subjective refraction, central corneal thickness, axial length, keratometry, intraocular pressure, corneal biomechanical properties and 24-month axial length data were retrieved and analysed.ResultsMultivariate analysis showed that there was significant negative correlation between axial elongation and baseline age and corneal hysteresis (p<0.05) in the SVS group. In the ortho-k group, only baseline age was significantly and negatively associated with axial elongation (p<0.01).ConclusionCorneal biomechanical properties and baseline age can predict the rate of axial elongation in myopic children. It may be beneficial for younger myopic children with low corneal hysteresis to commence ortho-k treatment as early as possible.

scholarly journals Internal Astigmatism and Its Role in the Growth of Axial Length in School-Age Children

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Liangcheng Wu ◽  
Chenghai Weng ◽  
Fei Xia ◽  
Xiaoying Wang ◽  
Xingtao Zhou
Keyword(s):  
Risk Factor ◽  
Linear Regression ◽  
Primary School ◽  
Axial Length ◽  
Regression Line ◽  
School Age Children ◽  
School Age ◽  
Paired Samples ◽  
The Difference

Objectives. To explore the role of internal astigmatism (IA) in the growth of axial length (AL) in school-age children. Methods. Total astigmatism (TA), corneal astigmatism (CA), and AL of all children in Jing’an District 2nd Centre Primary School in Shanghai were measured. In IA, the difference between TA and CA was also calculated using vector analysis. The association of axial length with IA, genders, and age was analyzed using linear regression. The difference of IA between both eyes was also calculated. The AL between both eyes was compared using paired samples t-test when DIA = 0 D, <0.5 D, and ≥0.5 D. Results. Six hundred and twelve cases (98.23%) in 623 children aged 7–12 yrs older entered into the study. Genders, age, and IA all affected AL. This could be represented by a linear regression line in the form AL = 21.46 − 0.43∗gender + 0.22∗age + 0.46∗IA (male = 1, female = 2; t=7.01, P<0.01 for sex; t=11.6, P<0.01 for age; and t=6.6, P<0.01 for IA; R2=0.16). The AL in the eye with larger IA was also longer when DIA was larger than 0.5 D (t=2.65, P<0.01). Conclusions. IA was observed to be associated with AL and might be a risk factor of the onset and progress of myopia in school-age children.

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