scholarly journals Multi-Factor Analysis of the Influence of Orthokeratology on Controlling Myopia in Adolescents

2020 ◽  
Author(s):  
Shijin Wen ◽  
Siqi Ma ◽  
Chuchu Xiao ◽  
Shengfa Hu ◽  
Xufang Ran ◽  
...  
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Age Groups ◽  
Pairwise Comparison ◽  
Length Change ◽  
Corneal Curvature ◽  
The Third ◽  
The Mean ◽  
The Difference ◽  
Clinical Records

Abstract Background To investigate which baseline factors are predictive for axial length growth over an average period of 1 years in a group of adolescents wearing orthokeratology (OK) contact lenses.Methods In this retrospective study, the clinical records of 189 new OK wearers (378 eyes) between 2014 and 2018 at Xiangya Hospital of Central South University were reviewed. The primary outcome measure was axial length change from baseline to the time of 1 year. Independent variables included baseline measures of age at initiation of OK wear, refractive error (spherical equivalent), corneal thickness, corneal curvature. (1) Age group, 8 ~ 10 years old is the first group, 10 ~ 13 years old is the second group, ≥13 years old is the third group; (2) Myopia degree group, ≥-3.00D is the first group, -3.00 ~ -6.00D is the second group, <-6.00D is the third group; (3) corneal thickness group, ≤550μm is the first group,> 550μm is the second group; (4) corneal curvature group, ≤42.0D is The first group, 42.0 ~ 44.0D is the second group,> 44.0D is the third group.Results ANOVA was used to analyze the difference between the baseline axial length of each group and the axial length for 1 year after continuous wearing of orthokeratology: (1)The mean axial difference between different age groups are 0.251mm, 0.033mm,and 0.112mm, and the difference of the three groups is not statistically significant (F=2.279，P=0.104). By pairwise comparison, only the difference between the first group and the third group is statistically significant (P=0.041); (2) The mean axial difference between different myopia degree groups are 0.173mm, 0.109mm and -0.008mm, and the difference of the three groups is statistically significant (F=8.340，P=0.000 ). By pairwise comparison, the difference between the first group and the second group is statistically significant (P=0.000) and the difference between the first group and the third group is statistically significant(P=0.016); (3) The mean axial difference between different corneal thickness groups and corneal curvature groups is not statistically significant.Conclusions OKs are effective in controlling axial length elongation and myopic progression in adolescents, particularly in younger children with higher myopia.

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 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

Correlation of iCare ic100 tonometry with iCare TA01i in screening of unselected population in Northern Finland Birth Cohort Eye study

2021 ◽  
pp. 112067212110143
Author(s):  
M Johanna Liinamaa ◽  
Katri Stoor ◽  
Ilmari Leiviskä ◽  
Ville Saarela
Keyword(s):  
Birth Cohort ◽  
Axial Length ◽  
Corneal Thickness ◽  
Mean Difference ◽  
Portable Devices ◽  
Corneal Curvature ◽  
Iop Measurement ◽  
Unselected Population ◽  
The Mean ◽  
The Right

Purpose: iCare tonometers are easy-to-use and portable devices for measuring the intraocular pressure (IOP). Purpose was to evaluate the IOP values measured by both novel iCare ic100 and conventional model TA01i devices in unselected population. Methods: IOP was measured with iCare ic100 and TA01i tonometers in 149 participants aged 32–33 years (born in 1985 or 1986) of the Northern Finland Birth Cohort Eye 2 study. The right eye of each participant was selected for analysis. We also collected data on axial length, corneal curvature and central corneal thickness (CCT). Bland-Altman plot was used for comparing the values obtained by these devices. Results: Mean IOP measured with the ic100 device was 13.8 (3.4) mmHg, with TA01i it was 12.5 (3.0) mmHg. The mean difference between these devices was 1.30 mmHg ( p < 0.001) and R2 was 0.694. In Bland-Altman analysis, the agreement between the two tonometers ic100 and TA01i was constantly good (mean difference −1.30, ic100 device showing higher measures). There was a correlation between IOP and CCT ( r = 0.269, p < 0.001 for ic100 and r = 0.255, p = 0.002 for TA01i), but not with IOP and corneal curvature or IOP and axial length. Conclusion: In summary, we found ic100 rebound tonometry to be both reliable and effective, although CCT may influence IOP measurements with ic100 and TA01i. Therefore, iCare ic100 is suitable for IOP measurement in large cohort studies.

scholarly journals ADULT MYOPES

2018 ◽  
Vol 25 (11) ◽  
pp. 1660-1666
Author(s):  
NuhaMohamed Fath Elrahman ◽  
AbdElaziz Mohamed Elmadina ◽  
Manzoor Ahmad Qureshi ◽  
Adil Mousa Younis ◽  
Muhammad Ijaz Ahmad ◽  
...  
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Cross Sectional Study ◽  
Age Group ◽  
Spherical Equivalent ◽  
Corneal Curvature ◽  
Sectional Study ◽  
Cross Sectional ◽  
Gender And Age ◽  
The Mean

Objectives: This study aimed to explore the correlation of central cornealthicknesses (CCT), mean keratometry (KM) and axial length (AL) to myopia degree in sphericalequivalent (SE) among Sudanese adults. Study Design: Cross sectional study. Setting:University Eye complex clinic and Makka Eye complex Omdurman. Period: April to October2015. Methods: Central Corneal Thickness (CCT), k-reading (KM), axial length and thedegree of refraction (SE) 0f 200 myopic eyes and 60 emmetropic eyes as a control groupwere measured. Results: Adult Sudanese females (57%) were found greater than males (43%)population; (χ 2 = 109.5, p = 0.000 ), most of the participants’ age was less than 25 years(χ 2 = 109.5, p = 0.000 ), and the mean myopic spherical equivalent (SE) was – 4.79 ± 2.55 D,ranging from -1.00 to -11.00 D. The mean CCT of the myopic group was 542.8 ±11.9 μm,while for the emmetropic group was 538.7 ±12.4 μm. The cornea were steeper in eyes withlonger axial length (r = 0.24, p =0.001). Eyes with higher myopic spherical equivalent hadlonger axial length (r =0.30, p <0.001). Mean keratometrys were steeper with increasing age(r= 0.24, p= 0.001). This study has shown that CCT has no correlation with degree of myopia(p= 0.46), gender (p= 0.99), and age (p= 0.07). The CCT, KM, and AL means for myopicparticipants were found significantly greater than emmetropic participants (p=0.000, 0.000,and 0.044 respectively. Conclusion: The females participants of myopia were higher rate thanmales, early adults’ age group were of higher rate myopic incident; there was no correlationbetween CCT and the degree of myopia, gender, and age. CCT, KM, and AL means for myopicwere found higher than emmetropic participant. Eyes with more myopic spherical equivalenthad longer axial length; corneal curvature mean becomes steeper with increasing age.

scholarly journals Evaluation of Anterior Chamber Depth in 28,709 Adult Cataract Patients in China using Swept-Source Optical Biometry

2021 ◽  
Author(s):  
Qiong Lei ◽  
Haixia Tu ◽  
Xi Feng ◽  
Yong Wang
Keyword(s):  
Cataract Surgery ◽  
Anterior Chamber ◽  
Axial Length ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Multivariate Regression Analysis ◽  
Swept Source ◽  
Mean Values ◽  
The Mean ◽  
Cataract Patients

Abstract Background: To create an anterior chamber depth (ACD) regression model for adult cataract surgery candidates from China, and to evaluate the distribution of their ocular biometric parameters.Methods: The ocular biometric records of 28,709 right eyes of cataract surgery candidates who were treated at Aier Eye Hospitals in nine cities from 2018 to 2019 were retrospectively analyzed. All measurements were taken with IOLMaster 700. We included patients who were at least 40 years old and were diagnosed with cataract.Results: The mean age of the patients was 68.6 ± 11.0 years. The mean values recorded were as follows: axial length (AL), 24.17 ± 2.47 mm; mean keratometry (Km) value, 44.09 ± 3.25 D; corneal astigmatism (CA), 1.06 ± 0.98 D; ACD, 3.02 ± 0.45 mm; lens thickness (LT), 4.52 ± 0.45 mm; central corneal thickness (CCT), 0.534 ± 0.04 mm; and white to white (WTW) corneal diameter, 11.64 ± 0.46 mm. The proportion of patients with long axial length (AL >25 mm) decreased with age. ACD, LT, AL, Km, WTW, and age were correlated. In the multivariate regression analysis of ACD, which included LT, AL, WTW, sex, Km, CCT, and age, there was a reasonable prediction with adjusted R2 = 0.629.Conclusions: The results show that high myopes are inclined to schedule cataract surgery at a younger age. LT and AL were found to be important factors that affect ACD. This study provides reference data for cataract patients from China.

scholarly journals Getting Vaccinated Helps: Prospective Study Reveals Lower CT Severity Scores amongst COVID Vaccine Recipients

2022 ◽  
Author(s):  
Priscilla C. Joshi ◽  
Vandana Jahanvi ◽  
Mangal S. Mahajan ◽  
Nivedita C. Ghule Patil ◽  
Priyankkumar G. Moradiya ◽  
...  
Keyword(s):  
Disease Severity ◽  
Age Groups ◽  
P Value ◽  
Disease Prognosis ◽  
Important Message ◽  
Severity Scores ◽  
Reduce Infection Rate ◽  
The Mean ◽  
The Difference ◽  
The Government

Abstract Context Computerized tomography (CT) is an invaluable imaging investigation for evaluating COVID-19 disease. CT detects early changes of COVID-19 pneumonia and predicts the disease prognosis based on a semiquantitative 25-point CT severity score (CT-SS). India launched its vaccination drive in January 2021 with two different vaccines being approved by the government. These vaccines are believed to prevent the disease itself, in majority of the cases and at least decrease disease severity, in the rest. Aim This study aims to evaluate the CT-SS in vaccinated and non-vaccinated subjects who have been diagnosed with COVID-pneumonia or are COVID suspects. Subjects and Methods A total of 3,235 patients with typical COVID-19 related imaging findings on HRCT thorax were included in the study. These subjects were divided into three age categories, 18–44, 45–59 and ≥60 years. The CT severity scores were allotted by experienced radiologists. Medians of the scores in different age groups were compared amongst vaccinated and non-vaccinated individuals using the Kruskal–Wallis H test. A p-value < 0.05 was considered significant. All results were shown with 95% confidence interval. Results The difference in the medians amongst the vaccinated and non-vaccinated groups was significant, p-values being < 0.001 in all age categories. Conclusion The mean CT-SS was less in vaccinated subjects and the difference in median CT-SS amongst vaccinated and non-vaccinated individuals was statistically significant, thus sending an important message that it is mandatory for the population at large to get vaccinated to reduce infection rate/disease severity.

scholarly journals Quantitative electroencephalography as a tool for objective neurophysiological seizure diagnosis: A retrospective study

2020 ◽  
Vol 0 ◽  
pp. 1-6
Author(s):  
Rajesh Kumar ◽  
Tribhuwan Kumar ◽  
Kamlesh Jha ◽  
Yogesh Kumar
Keyword(s):  
Energy Level ◽  
Matched Control ◽  
Age Groups ◽  
Quantitative Electroencephalography ◽  
Beta Band ◽  
Significant Difference ◽  
Males And Females ◽  
The Mean ◽  
The Difference ◽  
Electrical Activities

Objectives: Seizure is the fourth most common neurological disorder in the world; it affects all age groups with equal possibility of occurrence in both males and females. Many antiepileptic drugs are available today, but its diagnosis is challenging. The present study attempted to see if seizure activities could be predicted by analyzing the pre-seizure electrical activities. The prediction may help in taking preventive measures appropriately beforehand in the individuals with seizure proneness. Material and Methods: We selected 11 generalized seizure patients and 19 control patients out of total 115 patients referred for electro-diagnostics for various reasons. EEG of the subjects recorded, segmented as per protocol, and analyzed using MATLAB and EEGLAB tools. Results: The mean energy level in alpha and beta band of the study subject was significantly lower (P = 0.04 and 0.004, respectively) as compared to the age matched control subjects. Theta and delta bands did not show any significant difference between the groups. The difference between the pre- and post-electrical seizure energy and entropy was statistically insignificant. Conclusion: The study shows that the energy level remains low in the seizure patients in the alpha and beta bands. This further goes down when electrophysiological seizure activities starts. The randomness or entropy does not alter significantly among the seizure subjects in comparison to non-seizure subjects.

Effects of Orthokeratology Lens On Axial Length Elongation in Myopia With Anisometropia Children

2021 ◽  
Author(s):  
Ziyang Chen ◽  
Kai-Ming Chen ◽  
Ying Shi ◽  
Zhao-Da Ye ◽  
Sheng Chen ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Axial Length ◽  
Statistical Significance ◽  
Spherical Equivalent ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Better Than ◽  
Group 1

Abstract AimTo investigate the effect of orthokeratology (OK) lens on axial length (AL) elongation in myopia with anisometropia children.MethodsThirty-seven unilateral myopia (group 1) and fifty-nine bilateral myopia with anisometropia children were involved in this 1-year retrospective study. And bilateral myopia with anisometropia children were divided into group 2A (diopter of the lower SER eye under − 2.00D) and group 2B(diopter of the lower SER eye is equal or greater than − 2.00D). The change in AL were observed.The datas were analysed using SPSS 21.0.Results(1) In group 1, the mean baseline AL of the H eyes and L eye were 24.70 ± 0.89 mm and 23.55 ± 0.69 mm, respectively. In group 2A, the mean baseline AL of the H eyes and L eyes were 24.61 ± 0.84 mm and 24.00 ± 0.70 mm respectively. In group 2B, the mean baseline AL of the H eyes and L eyes were 25.28 ± 0.72 mm and 24.70 ± 0.74 mm. After 1 year, the change in AL of the L eyes was faster than the H eyes in group 1 and group 2A (all P<0.001).While the AL of the H eyes and L eyes had the same increased rate in group 2B. (2) The effect of controlling AL elongation of H eyes is consistent in three groups (P = 0.559).The effect of controlling AL elongation of L eyes in group 2B was better than that in group 1 and group 2A (P < 0.001). And the difference between group 1 and group 2A has no statistical significance. (3) The AL difference in H eyes and L eyes decreased from baseline 1.16 ± 0.55mm to 0.88 ± 0.68mm after 1 year in group 1.And in group 2A, the AL difference in H eyes and L eyes decreased from baseline 0.61 ± 0.34mm to 0.48 ± 0.28mm. There was statistically significant difference (all P<0.001). In group 2B, the baseline AL difference in H eyes and L eyes has no significant difference from that after 1 year (P = 0.069).ConclusionsMonocular OK lens is effective on suppression AL growth of the myopic eyes and reduce anisometropia value in unilateral myopic children. Binocular OK lenses only reduce anisometropia with the diopter of the low eye under − 2.00D. Binocular OK lenses cannot reduce anisometropia with the diopter of the low eye equal or greater than − 2.00D. Whether OK lens can reduce refractive anisometropia value is related to the spherical equivalent refractive of low refractive eye in bilateral myopia with anisometropia children after 1-year follow-up.

scholarly journals Age distribution and associated factors of cornea biomechanical parameter stress-strain index in Chinese healthy population

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Guihua Liu ◽  
Hua Rong ◽  
Ruxia Pei ◽  
Bei Du ◽  
Nan Jin ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Axial Length ◽  
Corneal Thickness ◽  
Age Distribution ◽  
Partial Least Square ◽  
Healthy Population ◽  
Corneal Curvature ◽  
Stress Strain ◽  
Strain Index ◽  
Biomechanical Parameter

Abstract Background To investigate the new cornea biomechanical parameter stress-strain index (SSI) in Chinese healthy people and the factors associated with SSI. Methods A total of 175 eyes from 175 participants were included in this study. Axial length was measured with the Lenstar LS-900. Pentacam measured curvature of the cornea and anterior chamber volume (ACV). Cornea biomechanical properties assessments were performed by corneal visualization Scheimpflug technology (Corvis ST). Student’s t-test, one-way ANOVA, partial least square linear regression (PLSLR) and linear mixed effects (LME) model were used in the statistical analysis. Results The mean (±SD) SSI was 1.14 ± 0.22 (range, 0.66–1.78) in all subjects and affected by age significantly after age of 35 (P < 0.05). In LME models, SSI was significantly associated with age (β = 0.526, P < 0.001), axial length (AL) (β = − 0.541, P < 0.001), intraocular pressure (IOP) (β = 0.326, P < 0.001) and steepest radius of anterior corneal curvature (RsF) (β = 0.229, P < 0.001) but not with ACV, biomechanical corrected intraocular pressure (bIOP), flattest radius of anterior corneal curvature (RfF) or central corneal thickness (CCT) (P > 0.05 for each). Conclusions SSI increased with age after the age of 35. In addition to age, SSI was positively correlated with RsF and IOP, while negatively correlated with AL.

On an inequality of long period in the motions of the Earth and Venus

1837 ◽  
Vol 3 ◽  
pp. 77-78
Keyword(s):  
Principal Term ◽  
The Sun ◽  
Method Of Calculation ◽  
The Third ◽  
Long Period ◽  
Mean Motion ◽  
The Earth ◽  
The Mean ◽  
The Difference

The author had pointed out, in a paper published in the Philosophical Transactions for 1828, on the corrections of the elements of Delambre’s Solar Tables, that the comparison of the corrections of the epochs of the sun and the sun’s perigee, given by the late observations, with the corrections given by the observations of the last century, appears to indicate the existence of some inequality not included in the arguments of those tables. As it was necessary, therefore, to seek for some inequality of long period, he commenced an examination of the mean motions of the planets, with the view of discovering one whose ratio to the mean motion of the earth could be expressed very nearly by a proportion of which the terms are small. The appearances of Venus are found to recur in very nearly the same order every eight years; some multiple, therefore, of the periodic time of Venus is nearly equal to eight years. It is easily seen that this multiple must be thirteen; and consequently eight times the mean motion of Venus is nearly equal to thirteen times the mean motion of the earth. The difference is about one 240th of the mean annual motion of the earth; and it implies the existence of an inequality of which the period is about 240 years. No term has yet been calculated whose period is so long with respect to the periodic time of the planets disturbed. The value of the principal term, calculated from the theory, was given by the author in a postscript to the paper above referred to. In the present memoir he gives an account of the method of calculation, and includes also other terms which are necessarily connected with the principal inequality. The first part treats of the perturbation of the earth’s longitude and radius victor; the second of the perturbation of the earth in latitude; and the third of the perturbations of Venus depending upon the same arguments.

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