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

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.

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Presbyopia and its anatomical and physiological variants

Nepalese Journal of Ophthalmology ◽

10.3126/nepjoph.v3i2.5269 ◽

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

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ADULT MYOPES

The Professional Medical Journal ◽

10.29309/tpmj/18.4855 ◽

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.

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

10.21203/rs.3.rs-60152/v1 ◽

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.

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Corneal Biomechanical Parameters and Central Corneal Thickness in Glaucoma Patients, Glaucoma Suspects, and a Healthy Population

Journal of Clinical Medicine ◽

10.3390/jcm10122637 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2637

Author(s):

Mª. Ángeles del Buey-Sayas ◽

Elena Lanchares-Sancho ◽

Pilar Campins-Falcó ◽

María Dolores Pinazo-Durán ◽

Cristina Peris-Martínez

Keyword(s):

Central Corneal Thickness ◽

Corneal Thickness ◽

Mean Difference ◽

The Other ◽

Control Group ◽

Healthy Population ◽

Diagnostic Categories ◽

Significant Difference ◽

Biomechanical Parameters ◽

The Mean

Purpose: To evaluate and compare corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), measurements were taken between a healthy population (controls), patients diagnosed with glaucoma (DG), and glaucoma suspect patients due to ocular hypertension (OHT), family history of glaucoma (FHG), or glaucoma-like optic discs (GLD). Additionally, Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated IOP (IOPcc) were compared between the different groups of patients. Methods: In this prospective analytical-observational study, a total of 1065 patients (one eye of each) were recruited to undergo Ocular Response Analyzer (ORA) testing, ultrasound pachymetry, and clinical examination. Corneal biomechanical parameters (CH, CRF), CCT, IOPg, and IOPcc were measured in the control group (n = 574) and the other groups: DG (n = 147), FHG (n = 78), GLD (n = 90), and OHT (n = 176). We performed a variance analysis (ANOVA) for all the dependent variables according to the different diagnostic categories with multiple comparisons to identify the differences between the diagnostic categories, deeming p < 0.05 as statistically significant. Results: The mean CH in the DG group (9.69 mmHg) was significantly lower compared to controls (10.75 mmHg; mean difference 1.05, p < 0.001), FHG (10.70 mmHg; mean difference 1.00, p < 0.05), GLD (10.63 mmHg; mean difference 0.93, p < 0.05) and OHT (10.54 mmHg; mean difference 0.84, p < 0.05). No glaucoma suspects (FHG, GLD, OHT groups) presented significant differences between themselves and the control group (p = 1.00). No statistically significant differences were found in the mean CRF between DG (11.18 mmHg) and the control group (10.75 mmHg; mean difference 0.42, p = 0.40). The FHG and OHT groups showed significantly higher mean CRF values (12.32 and 12.41 mmHg, respectively) than the DG group (11.18 mmHg), with mean differences of 1.13 (p < 0.05) and 1.22 (p < 0.001), respectively. No statistically significant differences were found in CCT in the analysis between DG (562 μ) and the other groups (control = 556 μ, FHG = 576 μ, GLD = 569 μ, OHT = 570 μ). The means of IOPg and IOPcc values were higher in the DG patient and suspect groups than in the control group, with statistically significant differences in all groups (p < 0.001). Conclusion: This study presents corneal biomechanical values (CH, CRF), CCT, IOPg, and IOPcc for diagnosed glaucoma patients, three suspected glaucoma groups, and a healthy population, using the ORA. Mean CH values were markedly lower in the DG group (diagnosed with glaucoma damage) compared to the other groups. No significant difference was found in CCT between the DG and control groups. Unexpectedly, CRF showed higher values in all groups than in the control group, but the difference was only statistically significant in the suspect groups (FHG, GLD, and OHT), not in the DG group.

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Usefulness of the Non-Contact Tonometry in Out-Patient Screening

Asian Journal of Ophthalmology ◽

10.35119/asjoo.v15i2.232 ◽

2016 ◽

Vol 15 (2) ◽

Author(s):

Satheesh Solomon T Selvin ◽

Chris Elsa Samson Jacob ◽

Thomas Kuriakose

Keyword(s):

Central Corneal Thickness ◽

Care Center ◽

Corneal Thickness ◽

Tertiary Care ◽

Cross Sectional Study ◽

Applanation Tonometry ◽

Cross Sectional ◽

Significant Difference ◽

Iop Measurement ◽

The Mean

Purpose: Goldmann applanation tonometry (GAT) is considered the gold standard for Intraocular Pressure (IOP) measurement. It has the disadvantages of being a contact device, need for a slit-lamp, non-portability and need of a skilled examiner. Many hospitals are using a Non Contact Tonometry (NCT) as a screening device to save clinician time, however the usefulness is not proved in terms of reliability. This study was aimed to determine the usefulness of the Air-puff tonometer (TONOREF NIDEK II, NIDEK CO., LTD., JAPAN) over a GAT in a tertiary care center. Design: Cross-sectional Study Methods: This was a cross-sectional, non interventional observational study conducted on 224 eyes (right eye) from 224 patients. All patients underwent the IOP measurement with both methods and a central corneal thickness (CCT) measured. The data was analyzed using SPSS 20.0 software. Results: The mean age of the patients was 40.3±11.29 years. There was a statistically significant difference (p<0.001) between the mean NCT and GAT readings which persisted even after correction for central corneal thickness. The correlation between NCT and GAT using Pearson’s correlation coefficient was strong irrespective of the corrections for their corneal thickness (r = 0.751 and 0.718 for uncorrected and corrected values respectively). The correlation of the individual clinicians for the readings varied from moderate to strong. The ROC curve showed the best sensitivity and specificity to occur at around 13 to 14 mmHg. Conclusion: NCT seems to overestimate the IOP at low ranges as compared to the GAT and underestimate at higher ranges. The crossover of the values is seen between 12 to 13 mmHg. The clinician should do an individualized analysis of his/her GAT measurements to the readings of the NCT machine at the clinic to obtain clinician specific nomogram.

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

10.21203/rs.3.rs-200270/v1 ◽

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.

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

BMC Ophthalmology ◽

10.1186/s12886-020-01704-6 ◽

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.

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Effects of SMILE Surgery on Intraocular Pressure, Central Corneal Thickness, Axial Length, Peripapillary Retinal Nerve Fiber Layer, and Macular Ganglion Cell Complex Thickness

Journal of Ophthalmology ◽

10.1155/2020/4934196 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Zhanlin Zhao ◽

Sylvain Michée ◽

Jean-François Faure ◽

Christophe Baudouin ◽

Antoine Labbé

Keyword(s):

Intraocular Pressure ◽

Ganglion Cell ◽

Nerve Fiber ◽

Axial Length ◽

Central Corneal Thickness ◽

Corneal Thickness ◽

Ganglion Cell Complex ◽

Fiber Layer ◽

Rnfl Thickness ◽

The Mean

Purpose. To evaluate the change in intraocular pressure (IOP), central corneal thickness (CCT), axial length, peripapillary retinal nerve fiber layer (RNFL) thickness, and macular ganglion cell complex (GCC) thickness after small incision lenticule extraction (SMILE) surgery. Methods. This prospective observational study was conducted in Espace Nouvelle Vision, Ophthalmological Clinic, Paris, France. Fifty eyes of 25 patients were enrolled in this study and underwent SMILE surgeries. IOP, central corneal thickness (CCT), axial length (AL), peripapillary RNFL thickness, and macular GCC thickness were measured before and at 3 months after SMILE. Results. The mean preoperative spherical equivalent was −3.15 ± 1.50 diopters (D), and the mean postoperative value was 0.15 ± 0.28 D. After SMILE surgery, IOP decreased from 15.03 ± 2.79 mmHg to 11.02 ± 2.73 mmHg and 10.02 ± 2.21 mmHg at 1 and 3 months, respectively ( P < 0.01 for both comparisons). The mean decrease in measured IOP as a function of ablation depth was 0.065 ± 0.031 mmHg/μm. CCT decreased from 545.98 ± 26.61 μm to 478.40 ± 30.26 μm after SMILE surgery ( P < 0.01 ). AL decreased from 24.80 ± 0.84 mm to 24.70 ± 0.83 mm ( P < 0.01 ). There was no statistically significant change in mean peripapillary RNFL or mean GCC thickness after SMILE surgery. Conclusions. SMILE surgery modified IOP measurement, CCT, and AL but did not change peripapillary RNFL and macular GCC thicknesses. The postoperative drop in measured IOP might be explained by the decreased CCT. An accurate re-evaluation of AL should be performed before cataract surgery among post-SMILE patients.

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Ocular biometry and power of intra ocular lens among cataract patients in rural Eastern Ethiopia

10.21203/rs.2.20424/v1 ◽

2020 ◽

Author(s):

MANDEFRO SINTAYEHU KASSA ◽

GIRUM W GESSESSE

Keyword(s):

Anterior Chamber ◽

Axial Length ◽

Anterior Chamber Depth ◽

Multiple Linear Regression Model ◽

P Value ◽

Corneal Curvature ◽

Ocular Lens ◽

Eastern Ethiopia ◽

Ocular Biometry ◽

The Mean

Abstract Background : The main objective of the study was to report on the main parameters of ocular biometry and Intra ocular lens power of patients attending a cataract surgical program in Eastern Ethiopia. Methods : The study was a cross sectional study on 765 eyes which were legible for cataract surgery during a mass eye camp conducted from April 04 to April 10, 2018 at Bisidimo Hospital,Eastern Ethiopia.Ocular biometric parameters such as axial length (AL), anterior chamber depth (ACD), mean corneal curvature (MCC) were measured using automated keratorefractometer(Retinomax) and Sonomed A - Scan. Analysis of variance and multivariate analysis were done to determine association of ocular biometry components with socio demography of the study subjects. Results : A total of 765 eyes were enrolled in this study. The mean corneal curvature and the mean anterior chamber depth were found to be 7.61 mm and 2.88mm respectively. The mean axial length was estimated to be 22.98 mm. The mean refractive power of Intra ocular lenses was calculated to be 19.34D. The mean axial length in females was shorter than that of males by 0.24 and this was statistically significant ( P - value = 0.01). Under multiple linear regression model gender had a statistically significant impact on the axial length. The mean Anterior chamber depth in males was also larger than that of females by nearly 0.1 and this was statistically significant (P - value = 0.001). Under multiple linear regression model both age and gender had a statistically significant impact on the anterior chamber depth. There was no a statistically significant difference on the mean Intra ocular lens power required for male and female patients.Conclusion : This study is the first of its kind to provide a larger population based normative data on the most important parameters of ocular biometry in Ethiopia.The female sex was a strong predictor of small axial length and shallow anterior chamber. Increasing age had no effect on the axial length but was found to be a stronger predictor of shallow anterior chamber. Key words : Axial length, Anterior chamber depth, Corneal curvature, Intra ocular lens.

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Age Distribution and Associated Factors of Cornea Biochemical Parameter Stress-Strain Index in Chinese Healthy Population

10.21203/rs.3.rs-56107/v1 ◽

2020 ◽

Author(s):

Guihua Liu ◽

Hua Rong ◽

Ruxia Pei ◽

Bei Du ◽

Nan Jin ◽

...

Keyword(s):

Intraocular Pressure ◽

Axial Length ◽

Regression Models ◽

Corneal Thickness ◽

Age Distribution ◽

Biochemical Parameter ◽

Healthy Population ◽

Corneal Curvature ◽

Stress Strain ◽

Strain Index

Abstract Background: To investigate the new cornea biochemical parameter stress-strain index (SSI) in Chinese healthy people and the factors associated with SSIMethods: A total of 175 eyes from 175 participants were recruited in this study. Axial length was measured with the Lenstar LS-900. Pentacam was used to measure curvature of the cornea and ACV and cornea biomechanical properties were measured by corneal visualization Scheimpflug technology (Corvis ST). Student’s t-test, one-way ANOVA, univariate and multivariate linear regression 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 univariate regression models, SSI did not vary with biomechanical intraocular pressure (bIOP) (P=0.989), steepest radius of anterior corneal curvature (RsF) (P=0.984) or central corneal thickness (CCT) (P=0.651). In multivariate regression models, SSI was significantly associated with age (β=0.557, P<0.001), axial length (AL) (β=-0.550, P<0.001), intraocular pressure (IOP) (β=0.377, P<0.001) and flattest radius of anterior corneal curvature (RfF) (β=0.222, P<0.001) but not with anterior chamber volume (ACV).Conclusions: SSI was increased by age after the age of 35. In addition to age, SSI and RfF, IOP is positively correlated and negatively correlated with AL.

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