scholarly journals Refractive lens power and lens thickness in children (6–16 years old)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tailiang Lu ◽  
Jike Song ◽  
Qiuxin Wu ◽  
Wenjun Jiang ◽  
Qingmei Tian ◽  
...  
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Univariate Analysis ◽  
Older Age ◽  
Curvature Radius ◽  
Corneal Curvature ◽  
Lens Thickness ◽  
Refractive Lens ◽  
Lens Power ◽  
North Western

AbstractTo examine the refractive lens power (RLP) and lens thickness and their associated factors in children from North-Western China. Children from two schools (primary school and junior high school) in the North-Western Chinese province of Qinghai underwent a comprehensive ophthalmic examination including biometry and cycloplegic refractometry. The RLP was calculated using Bennett’s equation. The study included 596 (77.9%) individuals (mean age: 11.0 ± 2.8 years; range: 6–16 years) with a mean axial length of 23.65 ± 1.24 mm (range: 20.02–27.96 mm). Mean lens thickness was 3.30 ± 0.16 mm (range: 2.85–3.99 mm) and mean RLP was 24.85 ± 1.98D (range: 19.40–32.97). In univariate analysis, girls as compared to boys had a significantly thicker lens and greater RLP, shorter axial length, smaller corneal curvature radius and shorter corneal curvature radius (all P < 0.001). Both sexes did not differ significantly in refractive error (P = 0.11) and corneal thickness (P = 0.16). RLP was positively associated with refractive error (correlation coefficient r = 0.33; P < 0.001) and lens thickness (r = 0.62; P < 0.001) and negatively with axial length (r =  − 0.70; P < 0.001). In univariate analysis, RLP decreased significantly with older age in the age group from age 6–13, while it plateaued thereafter, with no significant difference between boys and girls. In multivariate regression analysis, a higher RLP was associated with younger age (P < 0.001; standard regression coefficient β =  − 0.07), female sex (P < 0.001; β =  − 0.08), shorter axial length (P < 0.001; β =  − 0.48) and higher lens thickness (P < 0.001; β = 0.42). In Chinese children, RLP with a mean of 24.85 ± 1.98D decreases with older age, male sex, longer axial length, and thinner lens thickness. Changes in RLP and axial length elongation are important players in the emmetropization and myopization.

scholarly journals Refractive Lens Power and Lens Thickness in Children (6-16 Years Old)

2021 ◽  
Author(s):  
Tailiang Lu ◽  
Jike Song ◽  
Qiuxin Wu ◽  
Wenjun Jiang ◽  
Qingmei Tian ◽  
...  
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Univariate Analysis ◽  
Older Age ◽  
Curvature Radius ◽  
Corneal Curvature ◽  
Lens Thickness ◽  
Refractive Lens ◽  
Lens Power ◽  
North Western

Abstract Purpose: To examine the refractive lens power (RLP) and lens thickness and their associated factors in children from North-Western China.Methods: Children from two schools (primary school and junior high school) in the North-Western Chinese province of Qinghai underwent a comprehensive ophthalmic examination including biometry and cycloplegic refractometry. The RLP was calculated using Bennett’s equation. Results: The study included 596 (77.9%) individuals (mean age: 11.0±2.8 years; range: 6-16 years) with a mean axial length of 23.65±1.24mm (range: 20.02-27.96mm). Mean lens thickness was 3.30±0.16mm (range: 2.85-3.99mm) and mean RLP was 24.85±1.98D (range: 19.40-32.97). In univariate analysis, girls as compared to boys had a significantly thicker lens and greater RLP, shorter axial length, smaller corneal curvature radius and shorter corneal curvature radius (all P<0.001). Both sexes did not differ significantly in refractive error (P=0.11) and corneal thickness (P=0.16). RLP was positively associated with refractive error (correlation coefficient r=0.33; P<0.001) and lens thickness (r=0.62; P<0.001) and negatively with axial length (r=−0.70; P<0.001). In univariate analysis, RLP decreased significantly with older age in the age group from age 6-13, while it plateaued thereafter, with no significant difference between boys and girls. In multivariate regression analysis, a higher RLP was associated with younger age (P<0.001; standard regression coefficient β=−0.07), female sex (P<0.001; β=−0.08), shorter axial length (P<0.001; β=−0.48) and higher lens thickness (P<0.001; β=0.42). Conclusions: In Chinese children, RLP with a mean of 24.85±1.98D decreases with older age, male sex, longer axial length, and thinner lens thickness. Changes in RLP and axial length elongation are important players in the emmetropization and myopization.

Anterior Movement of the Crystalline Lens in the Process of Accommodation in Children

2007 ◽  
Vol 17 (4) ◽  
pp. 515-520 ◽  
Author(s):  
B.J. Kaluzny
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Crystalline Lens ◽  
Posterior Pole ◽  
Anterior Pole ◽  
Forward Movement ◽  
Ophthalmic Examination ◽  
Lens Thickness ◽  
Lens Position ◽  
Refractive Status

Purpose To investigate changes of crystalline lens position during accommodation in children with emmetropia, myopia, and hyperopia. Methods A total of 188 children (372 eyes) from 4 to 19 years old (mean age 11.3±4.43) with cycloplegic refractive error within a range +9.00 D to −9.00 D were enrolled. After a general ophthalmic examination, ultrasound biometry was performed, with the eye at a maximal accommodative effort. Cycloplegia was induced by triple installation of 1% tropicamide drops and 30 minutes later the biometric examination was repeated. Results In emmetropic eyes in the process of accommodation, the anterior pole of the crystalline lens moved forward by 0.144±0.14 mm (p ≤ 0.001); the position of the posterior pole did not change. In myopic eyes, the anterior pole moved forward by 0.071±0.13 mm (p≤0.001) and the posterior pole moved backward by 0.039±0.10 mm (p=0.003). In hyperopic eyes, the whole lens translocated anteriorly: anterior pole moved forward by 0.242±0.16 mm (p≤ 0.001) and posterior pole moved forward by 0.036±0.09 mm (p≤0.001). Differences among emmetropia, myopia, and hyperopia were statistically significant. Forward movement of the posterior pole correlated with a low axial length of the eye, and also with plus refractive error and with a smaller accommodative increase of lens thickness. Conclusions In children, accommodative changes of the crystalline lens position depend on refractive status.

scholarly journals A cross sectional clinical study on correlation between myopia and intraocular pressure and ocular biometric values among adults in tertiary eye care in Palakkad, Kerala, India

2018 ◽  
Vol 6 (8) ◽  
pp. 2790
Author(s):  
Raja A. M. ◽  
Rajendraprasad A. ◽  
Seema G.
Keyword(s):  
Clinical Study ◽  
Anterior Chamber ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
Corneal Curvature ◽  
College Hospital ◽  
Cross Sectional ◽  
Intra Ocular Pressure ◽  
Lens Thickness ◽  
Ocular Pressure

Background: To find out whether there is a correlation between intra ocular pressure and ocular biometric values like corneal curvature, anterior chamber depth, lens thickness and vitreous chamber depth in myopic eyes.Methods: A cross sectional clinical study was conducted in karuna medical college hospital Palakkad Kerala, India from September 2015 to August 2017. 1000 eyes of 500 myopic patients attending the ophthalmology OPD were included in this study. Goldman applanation tonometry was used to measure intra ocular pressure. Bausch and Lomb keratometer was used to measure corneal curvature and Biometer A scan machine was used to measure anterior chamber depth, lens thickness, vitreous chamber depth and axial length.Results: In this study majority of the patients age group was 16-20 years. The overall mean intra ocular pressure was 15mmhg and mean radius of corneal curvature was 44.12D. In this study average anterior chamber depth was 3.55mm and mean lens thickness was 3.56mm.Mean vitreous chamber depth was 18.40. In this study mean axial length was 24.60mm.Conclusions: Amount of myopia and variation in corneal curvature was not statistically significant. There was no correlation between intra ocular pressure and degree of myopia. But anterior chamber depth, lens thickness, vitreous chamber depth and axial length were statistically very significant with amount of myopia.

scholarly journals The biometric parameters of aniso-astigmatism and its risk factor in Chinese preschool children: the Nanjing Eye Study

2020 ◽  
Author(s):  
Haohai Tong ◽  
Qingfeng Hao ◽  
Zijin Wang ◽  
Yue Wang ◽  
Rui Li ◽  
...  
Keyword(s):  
Risk Factors ◽  
Logistic Regression ◽  
Axial Length ◽  
Apgar Score ◽  
Curvature Radius ◽  
Corneal Curvature ◽  
Multivariate Logistic Regression ◽  
Maternal Risk ◽  
Biometric Parameters ◽  
Term Delivery

Abstract BackgroundsTo determine the biometric components of aniso-astigmatism and associated maternal risk factors in Chinese preschool children.MethodsIn the population-based, cohort Nanjing Eye Study, children were measured for noncycloplegic refractive error using an autorefractor and for biometric parameters using an optical low-coherent reflectometry. The difference of total astigmatism (TA) between both eyes was calculated using cylinder power (non-vectorial aniso-TA was defined as ≥ 1.00 Dioptre Cylinder [DC] between both eyes) and by vector analysis (vectorial aniso-TA was defined as a difference of ≥ 0.5 in J0 or J45 between both eyes which is equivalent to 1.00 DC). The prevalence of aniso-TA was presented. Interocular biometric parameters were compared between with vs. without aniso-astigmatism group. In addition, risk factors were determined using multivariate logistic regression model.ResultsOf 1131 children (66.90 ± 3.38 months, 53.31% male), the prevalence of non-vectorial aniso-TA was 1.95% (95% Confidence Interval (CI) = 1.14%-2.75%), while the prevalence of vectorial aniso-TA was twice as common as non-vectorial aniso-TA, neither varying with sex or age. With aniso-TA eyes were more asymmetric in axial length and corneal curvature radius than without aniso-TA eyes. In multivariate logistic regression model, 5-min apgar score less than 7 was significantly associated with higher risk of aniso-TA (vectorial aniso-TA: Odds Ratio (OR) = 6.42, 95%CI = 2.63–15.69, P < 0.001; non-vectorial aniso-TA: OR = 4.92, 95%CI = 1.41–17.68, P = 0.01). Being twin or triple was significantly associated with higher risk of vectorial aniso-CA (OR = 2.43, 95%CI = 1.05–5.60, P = 0.38). Pre-term delivery (OR = 2.60, 95%CI = 1.09–6.15, P = 0.03) and post-term delivery (OR = 3.61, 95%CI = 1.31–9.96, P = 0.01) were significantly associated with higher risk of vectorial aniso-CA.ConclusionsBoth corneal curvature radius and axial length asymmetry were correlated with aniso-TA. Children with 5-min apgar score < 7 were more likely to have aniso-TA, while twin or triple, pre-term or post-term delivery were risk factors for vectorial aniso-CA.

scholarly journals Presbyopia and its anatomical and physiological variants

1970 ◽  
Vol 3 (2) ◽  
pp. 155-158
Author(s):  
M Gupta ◽  
RR Sukul ◽  
Y Gupta ◽  
M Dey ◽  
A Phougat ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Axial Length ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Physiological Parameters ◽  
Corneal Curvature ◽  
Lens Thickness ◽  
Significant Difference ◽  
The Mean

Aim: To study the various ocular anatomical and physiological parameters in presbyopia. Materials and methods: We studied the various ocular anatomical and physiological parameters like corneal curvature (keratometry readings: K1 and K2), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT) and axial length (AL) in 100 presbyopic patients between 35 - 55 years of age. The patients were divided into two age groups: I (35 – 44 years) and II (45-55 yrs). ACD, AL and LT were measured using an Ascan. CCT was measured with ultrasonic pachymetry. Results: The CCT decreased (BE), LT increased and ACD decreased (RE) significantly with increasing age (p < 0.05). There was no significant difference in males and females. Nearly 3/4th of the total increase in lens thickness was responsible for the decrease in the anterior chamber depth and the rest, 1/4th , goes posteriorly. Corneal curvature and AL showed no significant change with age. Conclusions: The mean of CCT decreased significantly with advancing age. As age increased, the mean value of lens thickness increased and anterior chamber depth decreased. Nearly 3/ 4th of total increase in LT was anteriorly, decreasing the ACD. Corneal curvature and AL has no relation with age. Key words: Presbyopia, central corneal thickness, anterior chamber depth, lens thickness, axial length DOI: http://dx.doi.org/10.3126/nepjoph.v3i2.5269 Nepal J Ophthalmol 2011; 3(2): 155-158

scholarly journals Effects of Hyperoxia on the Refraction in Murine Neonatal and Adult Models

2019 ◽  
Vol 20 (23) ◽  
pp. 6014
Author(s):  
Kiwako Mori ◽  
Toshihide Kurihara ◽  
Xiaoyan Jiang ◽  
Shin-ichi Ikeda ◽  
Ayako Ishida ◽  
...  
Keyword(s):  
Axial Length ◽  
Curvature Radius ◽  
Corneal Curvature ◽  
Future Studies ◽  
Oxygen Exposure ◽  
Adult Mice ◽  
Significant Difference ◽  
Myopic Shift ◽  
Neonatal Hyperoxia

Whether hyperoxia affects the refraction in neonatal and adult mice is unknown. The mice exposed to 85% oxygen at postnatal 8 days (P8d) for 3 days and the mice exposed to normal air were assigned to the neonatal hyperoxia and normoxia groups, respectively. The refraction, the corneal curvature radius (CR) and the axial length (AL) were measured at P30d and P47d. Postnatal 6 weeks (P6w) adult mice were divided into the adult hyperoxia and normoxia groups. These parameters were measured before oxygen exposure, after 1 and 6 weeks, and every 7 weeks. The lens elasticity was measured at P7w and P26w by enucleation. The neonatal hyperoxia group showed a significantly larger myopic change than the neonatal normoxia group (P47d −6.56 ± 5.89 D, +4.11 ± 2.02 D, p < 0.001), whereas the changes in AL were not significantly different (P47d, 3.31 ± 0.04 mm, 3.31 ± 0.05 mm, p = 0.852). The adult hyperoxia group also showed a significantly larger myopic change (P12w, −7.20 ± 4.09 D, +7.52 ± 2.54 D, p < 0.001). The AL did not show significant difference (P12w, 3.44 ± 0.03 mm, 3.43 ± 0.01 mm, p = 0.545); however, the CR in the adult hyperoxia group was significantly smaller than the adult normoxia group (P12w, 1.44 ± 0.03 mm, 1.50 ± 0.03 mm, p = 0.003). In conclusion, hyperoxia was demonstrated to induce myopic shift both in neonatal and adult mice, which was attributed to the change in the CR rather than the AL. Elucidation of the mechanisms of hyperoxia and the application of this result to humans should be carried out in future studies.

scholarly journals Lens thickness and associated ocular biometric factors among cataract patients in Shanghai

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jiaqi Meng ◽  
Ling Wei ◽  
Wenwen He ◽  
Jiao Qi ◽  
Yi Lu ◽  
...  
Keyword(s):  
Older Patients ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Male Gender ◽  
Older Age ◽  
Corneal Curvature ◽  
Lens Thickness ◽  
The Mean ◽  
Cataract Patients

Abstract Background To evaluate the distribution of lens thickness (LT) and its associations with other ocular biometric factors among cataract patients in Shanghai. Methods Twenty-four thousand thirteen eyes from 24,013 cataract patients were retrospectively included. Ocular biometric factors including LT, central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW) distance, anterior corneal curvature, and axial length (AL) were obtained using the IOLMaster700. The associations between LT and general or ocular factors were assessed. Results The mean age was 62.5 ± 13.6 years and 56.1% were female. The mean LT was 4.51 ± 0.46 mm. The LT was greater in older patients (P < 0.001). LT was positively correlated with CCT, while negatively correlated with ACD, WTW, and anterior corneal curvature (P < 0.001). Multivariate analysis revealed that increased LT was associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature (P < 0.001). LT changed with a variable behavior according to AL. In short eyes LT increased as AL increased, then decreased with longer AL in normal eyes and moderate myopic eyes, but increased again as AL increased in highly myopic eyes. Thickest LT was found in the 20.01–22 mm AL group. The correlation between LT and other biometric factors remained significant when stratified by ALs. Conclusions In a large Chinese cataractous population, we found that the thicker lens may be associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature. As AL increased, the change of LT was nonlinear, with the thickest lens seen in the 20–22 mm AL group.

scholarly journals Is a large eye size a risk factor for myopia? A Mendelian randomization study

2017 ◽  
Author(s):  
Keyword(s):  
Risk Factor ◽  
Risk Score ◽  
Refractive Error ◽  
Axial Length ◽  
Genetic Risk ◽  
Causal Effect ◽  
Genetic Risk Score ◽  
Mendelian Randomisation ◽  
Corneal Curvature ◽  
Eye Size

AbstractMyopia (nearsightedness) is an increasingly common cause of irreversible visual impairment. The ocular structures with greatest impact on refractive error are corneal curvature and axial length. Emmetropic eyes range in size within and across species, yet possess a balance between corneal curvature and axial length that is under genetic control. This scaling goes awry in myopia: 1 mm axial elongation is associated with ~3 Dioptres (D) myopia. Evidence that eye size prior to onset is a risk factor for myopia is conflicting. We applied Mendelian randomisation to test for a causal effect of eye size on refractive error. Genetic variants associated with corneal curvature identified in emmetropic eyes (22,180 individuals) were used as instrumental variables and tested for association with refractive error (139,697 individuals). A genetic risk score for the variants was tested for association with corneal curvature and axial length in an independent sample (315 emmetropes). The genetic risk score explained 2.3% (P=0.007) and 2.7% (P=0.002) of the variance in corneal curvature and axial length, respectively, in the independent sample, confirming these variants are predictive of eye size in emmetropes. The estimated causal effect of eye size on refractive error was + 1.41 D (95% CI. 0.65 to 2.16) less myopic refractive error per mm flatter cornea (P<0.001), corresponding to +0.48 D (95% CI. 0.22 to 0.73) more hypermetropic refractive error for an eye with a 1mm longer axial length. These results do not support the hypothesis that a larger eye size is a risk factor for myopia. We conclude the genetic determinants of normal eye size are not shared with those influencing susceptibility to myopia.

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