scholarly journals Repeatability and Reproducibility of Intraocular Pressure and Dynamic Corneal Response Parameters Assessed by the Corvis ST

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Bernardo T. Lopes ◽  
Cynthia J. Roberts ◽  
Ahmed Elsheikh ◽  
Riccardo Vinciguerra ◽  
Paolo Vinciguerra ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Standard Deviation ◽  
Healthy Volunteers ◽  
Coefficient Of Variation ◽  
Random Order ◽  
Good Precision ◽  
Corvis St ◽  
Deformation Amplitude ◽  
Repeatability And Reproducibility ◽  
Healthy Eyes

Purpose. To assess the repeatability and reproducibility of dynamic corneal response parameters measured by the Corvis ST (Oculus, Wetzlar, Germany). Methods. One eye randomly selected from 32 healthy volunteers was examined by the Corvis ST. Three different devices were used in an alternated random order for taking three measurements at each device in each subject. Standard intraocular pressure (IOP), the biomechanical-compensated IOP (bIOP), and DCR parameters were evaluated. The within-subject standard deviation (ζw) and coefficient of variation (CV) were assessed. Results. Regarding pressure indices, the ζw was below 1 mmHg for repeatability (0.98 for IOP and 0.89 for bIOP) and the CV was 6.6% for IOP and 6.1% for bIOP. For reproducibility, the ζw was around 1 mmHg (1.12 for IOP and 1.05 for bIOP) and the CV was 7.6% for IOP and 7.1% for bIOP. Most of DCR indices presented CV for repeatability below 4%. For reproducibility, the CV of most of the indices were below 6%. The deformation amplitude (DA) ratio in 1 mm and integrated radius were below 4% (1.2% and 3.8%, resp.). Conclusions. The Corvis ST showed good precision (repeatability and reproducibility) for IOP measurements and for DCR in healthy eyes.

scholarly journals Repeatability and Reproducibility of Measurements Using a NT-530P Noncontact Tono/Pachymeter and Correlation of Central Corneal Thickness with Intraocular Pressure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Fusako Fujimura ◽  
Kazutaka Kamiya ◽  
Kazuko Fujiwara ◽  
Nobuyuki Shoji ◽  
Kimiya Shimizu
Keyword(s):  
Intraocular Pressure ◽  
Healthy Volunteers ◽  
Coefficient Of Variation ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Limits Of Agreement ◽  
Repeatability And Reproducibility ◽  
Linear Correlations

Purpose. To investigate the repeatability and reproducibility of intraocular pressure (IOP) and central corneal thickness (CCT) measurements using a noncontact tono/pachymeter (NT-530P) and to assess the correlation of CCT with IOP.Methods. Forty-six eyes of healthy volunteers were measured by two examiners. Three consecutive measurements per eye were performed. Repeatability was assessed using the coefficient of variation, and reproducibility was assessed using Bland-Altman plots. Linear correlations were used to determine agreement between CCT and noncorrected IOP and CCT and corrected IOP, which was calculated using a formula built into the NT-530P.Results. The coefficient of variation for IOP was 6.4% and for CCT was 0.4%. The 95% limits of agreement between examiners were−0.17±1.42 mmHg (range:−2.95to 2.61 mmHg) for IOP,−0.93±4.37 μm (range:−9.50to 7.64 μm) for CCT. The corrected IOP was significantly higher than the noncorrected IOP (P=0.010.3). The noncorrected IOP significantly correlated with CCT (r=−0.4883,P=0.0006). The corrected IOP showed no significant correlation with CCT (r=−0.0285,P=0.8509).Conclusions. NT-530P offered repeatability and reproducibility in both IOP and CCT measurements. The corrected IOP calculated using the NT-530P was independent of the CCT, suggesting that this IOP may be less influenced by the central corneal thickness.

scholarly journals Corneal Biomechanical Assessment Using Corneal Visualization Scheimpflug Technology in Keratoconic and Normal Eyes

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lei Tian ◽  
Yi-Fei Huang ◽  
Li-Qiang Wang ◽  
Hua Bai ◽  
Qun Wang ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Corneal Thickness ◽  
Area Under The Curve ◽  
Biomechanical Properties ◽  
Corvis St ◽  
Biomechanical Assessment ◽  
Deformation Amplitude ◽  
Biomechanical Parameters ◽  
And Control ◽  
Corneal Biomechanical Properties

Purpose. To compare the corneal biomechanical properties of keratoconic patients and age-matched controls using corneal visualization Scheimpflug technology (Corvis ST).Methods. Sixty keratoconic eyes from 47 keratoconus patients and 60 normal eyes from 60 controls were enrolled in this prospective study. Tomography and biomechanical parameters of all eyes were obtained with the Pentacam and Corvis ST, respectively. Intraocular pressure was measured using a Goldmann applanation tonometer.Results.The tomography and biomechanical parameters of the keratoconic corneas were significantly different from those of the normal corneas except for the anterior chamber angle, first applanation length, the highest concavity time, and peak distance. The deformation amplitude was the best predictive parameter (area under the curve: 0.882), with a sensitivity of 81.7%, although there was a significant overlap between keratoconic and normal corneas that ranged from 1.0 to 1.4 mm. In both the keratoconus and control groups, the deformation amplitude was negatively correlated with intraocular pressure, central corneal thickness, and corneal volume at 3 and 5 mm.Conclusions. Corvis ST offers an alternative method for measuring corneal biomechanical properties. The possibility of classifying keratoconus based on deformation amplitude deserves clinical attention.

scholarly journals Repeatability and Reproducibility of a Quantitative Assessment of the Retinal Vascular Network Fractal Dimension Measured With Swept-source Optical Coherence Tomography Angiography in Healthy Eyes

2021 ◽  
Author(s):  
Déa Haddad ◽  
Louis Arnould ◽  
Florian Baudin ◽  
Pierre-Henry Gabrielle ◽  
Marc Sarossy ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Fractal Dimension ◽  
Healthy Volunteers ◽  
Optical Coherence Tomography Angiography ◽  
Vascular Network ◽  
Swept Source ◽  
Capillary Plexus ◽  
Repeatability And Reproducibility ◽  
The Mean ◽  
Healthy Eyes

Abstract Background: To evaluate the repeatability and reproducibility of the retinal vascular network fractal dimension (FD) measured from swept-source optical coherence tomography angiography (SS-OCTA) images of healthy eyes. Methods: A cross-sectional study was undertaken with young healthy volunteers who had no reported cardiac risk factors or ocular disease history. For each participant, three SS-OCTA images (12×12 mm) were acquired using the Cirrus Plex Elite 9000 (Carl Zeiss Meditec AG, Jena, Germany) by two ophthalmologists. The data from one eye per participant were retained for analysis. Automated segmentation was obtained from both the superficial and deep capillary plexuses. Fractal box-counting analyses were performed. The intraclass correlation coefficients (ICC) and the coefficient of variation (CV) were used as measures for repeatability and reproducibility. Results: A total of 43 eyes of healthy volunteers were included. The mean ± standard deviation (SD) age was 30 ± 6.2 years. The mean retinal vascular network FD was 1.693 in the superficial and 1.694 in the deep vascular layer in our healthy cohort. For repeatability, the ICC was 0.722 (95% CI, 0.541–0.839) in the superficial capillary plexus and 0.828 (95% CI, 0.705–0.903) in the deep capillary plexus. For reproducibility, the ICC was 0.651 (95% CI, 0.439–0.795) and 0.363 (95% CI, 0.073–0.596) at the superficial and deep capillary plexus, respectively. The CV for each observer was less than 5% in the two plexuses.Conclusions: In this study, the retinal vascular network FD provided new repeatability and reproducibility quantitative data using SS-OCTA with healthy participants.

scholarly journals Precision and Agreement of Central Corneal Thickness Measured with E-pach, A-scan, Corvis ST and Pentacam

2019 ◽  
Author(s):  
Anqi Liu ◽  
Zequan Xu ◽  
Jingjing Wang ◽  
Feng Liu ◽  
Yanming Jiang ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Limits Of Agreement ◽  
Interobserver Reproducibility ◽  
Corvis St ◽  
Test Study ◽  
Repeatability And Reproducibility ◽  
Healthy Eyes

Abstract Purpose To assess the precision (repeatability and reproducibility) and agreement of central corneal thickness (CCT) measurements by E-pach, Pentacam, Corvis ST and A-scan devices in healthy eyes. Methods Instrument diagnostic test study. A total of 100 patients were enrolled to measure right-eye CCT by E-pach, Pentacam, Corvis ST, and A-scan devices. To assess repeatability and reproducibility, the test-retest repeatability (TRT) and intraclass correlation coefficient (ICC) were calculated. The agreement among the four devices was evaluated with Bland-Altman plots. Results The E-pach showed repeatability (ICC=0.9981), interobserver reproducibility (ICC=0.9971) and intersession reproducibility (ICC=0.9825); the Pentacam, Corvis ST and A-scan also showed similar repeatability (all ICC≥0.9679), interobserver reproducibility (all ICC≥0.9730) and intersession reproducibility (all ICC≥0.9647). However, the E-pach yielded CCT values that were obviously lower than those of the A-scan and Pentacam (P<0.001) but higher than those of the Corvis ST (P<0.001). The 95% limits of agreement (LoA) in the Bland-Altman plots were 44.5 µm (E-pach vs. A-scan), 34.9 µm (E-pach vs. Corvis CT) and 32.5 µm (E-pach vs. Pentacam). Conclusions The E-pach is a portable, reliable and inexpensive pachymeter. However, the CCT values obtained from the E-pach are not interchangeable with those from Pentacam, Corvis ST and A-scan devices.

scholarly journals Evaluation of Central Corneal Thickness Using Corneal Dynamic Scheimpflug Analyzer Corvis ST and Comparison with Pentacam Rotating Scheimpflug System and Ultrasound Pachymetry in Normal Eyes

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ayong Yu ◽  
Weiqi Zhao ◽  
Giacomo Savini ◽  
Zixu Huang ◽  
Fangjun Bao ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Coefficient Of Variation ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Limits Of Agreement ◽  
Corvis St ◽  
Ultrasound Pachymetry ◽  
Repeatability And Reproducibility ◽  
High Repeatability

Purpose.To assess the repeatability and reproducibility of central corneal thickness (CCT) measurements by corneal dynamic Scheimpflug analyzer Corvis ST in normal eyes and compare the agreement with Pentacam rotating Scheimpflug System and ultrasound pachymetry.Methods.84 right eyes underwent Corvis ST measurements performed by two operators. The test-retest repeatability (TRT), within-subject coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to evaluate the intraoperator repeatability and interoperator reproducibility. CCT measurements also were obtained from Pentacam and ultrasound pachymetry by the first operator. The agreement between the three devices was evaluated with 95% limits of agreement (LoA) and Bland-Altman plots.Results.Corvis ST showed high repeatability as indicated by TRT ≤ 13.0 μm, CoV < 0.9%, and ICC > 0.97. The interoperator reproducibility was also excellent. The CoV was <0.9%, and ICC was >0.97. Corvis ST showed significantly lower values than Pentacam and ultrasound pachymetry (P<0.001). The 95% LoA between Corvis ST and Pentacam or ultrasound pachymetry were −15.8 to 9.5 μm and −27.9 to 12.3 μm, respectively.Conclusions.Corvis ST showed excellent repeatability and interoperator reproducibility of CCT measurements in normal eyes. Corvis ST is interchangeable with Pentacam but not with ultrasound pachymetry.

scholarly journals The RELIEF study: Tolerability and efficacy of preservative-free latanoprost in the treatment of glaucoma or ocular hypertension

2018 ◽  
Vol 29 (2) ◽  
pp. 210-215 ◽  
Author(s):  
Marta Misiuk-Hojlo ◽  
Maria Pomorska ◽  
Malgorzata Mulak ◽  
Marek Rekas ◽  
Joanna Wierzbowska ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Intraocular Pressure ◽  
Standard Deviation ◽  
Ocular Hypertension ◽  
Benzalkonium Chloride ◽  
Tear Film ◽  
Corrected Visual Acuity ◽  
Break Up ◽  
Preservative Free ◽  
Best Corrected Visual Acuity

Purpose: To assess tolerability and efficacy following a switch from benzalkonium chloride–latanoprost to preservative-free latanoprost in patients with glaucoma or ocular hypertension. Methods: A total of 140 patients with glaucoma or ocular hypertension controlled with benzalkonium chloride-latanoprost for at least 3 months were switched to treatment with preservative-free latanoprost. Assessments were made on days 15, 45, and 90 (D15, D45, and D90) and included best-corrected visual acuity, intraocular pressure, slit lamp examination, fluorescein staining, tear film break-up time, patient symptom evaluation, and subjective estimation of tolerability. Results: Mean best-corrected visual acuity remained unchanged during the study. Mean intraocular pressure compared with baseline (D0) remained stable throughout the study (D0, 15.9 mmHg (standard deviation = 2.6); D90, 15.3 mmHg (standard deviation = 2.4); p < 0.006). Tear film break-up time improved or remained unchanged relative to baseline in 92% of patients at D45 and in 93% at D90. Moderate-to-severe conjunctival hyperemia was seen in 56.8% of patients at D0, but this figure decreased to 13.7%, 2.2%, and 1.6% at D15, D45, and D90, respectively. Subjective assessment of tolerability (0–10 scale) indicated improvement with change of therapy (mean score: 5.3 (standard deviation = 2.2) at D0 versus 1.9 (standard deviation = 1.7) at D90; p < 0.0001). Conclusion: Preservative-free latanoprost has at least the same intraocular pressure-lowering efficacy as benzalkonium chloride–latanoprost, with a better tolerability profile. This may translate into greater control of treatment and improved quality of life.

Long-term intraocular pressure changes after femtosecond laser–assisted cataract surgery in healthy eyes and glaucomatous eyes

2019 ◽  
Vol 45 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Avni A. Shah ◽  
Jeanie Ling ◽  
Niraj R. Nathan ◽  
Ashton J. Kalhorn ◽  
Qingxia Chen ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Femtosecond Laser ◽  
Cataract Surgery ◽  
Pressure Changes ◽  
Healthy Eyes

scholarly journals Effects of unoprostone on diurnal variation of intraocular pressure in healthy volunteers

2011 ◽  
pp. 1003
Author(s):  
Kenji Inoue ◽  
Mieko Masumoto ◽  
Masato Wakakura ◽  
Goji Tomita
Keyword(s):  
Intraocular Pressure ◽  
Diurnal Variation ◽  
Healthy Volunteers

Clinical evaluation of the repeatability of ocular aberrometry obtained with a new pyramid wavefront sensor

2018 ◽  
Vol 29 (6) ◽  
pp. 585-592 ◽  
Author(s):  
Ana B Plaza-Puche ◽  
Liberdade C Salerno ◽  
Francesco Versaci ◽  
Daniel Romero ◽  
Jorge L Alio
Keyword(s):  
Standard Deviation ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Pupil Size ◽  
Pupil Diameter ◽  
Intraclass Correlation ◽  
Wavefront Sensor ◽  
Mean Square ◽  
The Subject ◽  
Healthy Eyes

Purpose:To evaluate the intrasubject repeatability of the ocular aberrometry obtained with a new ocular pyramidal aberrometer technology in a sample of normal eyes.Methods:A total of 53 healthy eyes of 53 subjects with ages ranging from 18 to 45 years were included in this study. In all cases, three consecutive acquisitions were obtained. Intrasubject repeatability of the measurements with a pyramidal aberrometer was calculated. Intrasubject repeatability for 4.0- and 6.0-mm pupils was evaluated within the subject standard deviation (Sw) and intraclass correlation coefficient.Results:Low values of the Swand intraclass correlation coefficient outcomes close to 1 were observed for the sphere and cylinder at 3.0-mm pupil size. Most low Swand intraclass correlation coefficient values close to 1 were observed for total, low-order aberrations and higher-order aberrations root mean square and for each Zernike coefficient analysis (intraclass correlation coefficient ⩾0.798) at 4.0-mm pupil size, with more limited outcomes for the aberrometric coefficient of Z(4, 4) with an intraclass correlation coefficient of 0.683. For a 6.0 mm pupil diameter, low Swand intraclass correlation coefficient values close to 1 were observed for all aberrometric parameters or Zernike coefficients analyzed (intraclass correlation coefficient ⩾0.850).Conclusion:The new pyramidal aberrometer Osiris provides repeatable and consistent measurements of ocular aberrometry measurements in normal eyes.

scholarly journals Classification of the coefficient of variation to variables in beef cattle experiments

2017 ◽  
Vol 47 (11) ◽  
Author(s):  
Marcos André Braz Vaz ◽  
Paulo Santana Pacheco ◽  
Enio Júnior Seidel ◽  
Angela Pellegrin Ansuj
Keyword(s):  
Standard Deviation ◽  
Beef Cattle ◽  
Coefficient Of Variation ◽  
Theses And Dissertations

ABSTRACT: This research was conducted to propose a classification of the coefficient of variation (CV%) in many categories of variables of production and carcass of beef cattle experiments. The data was collected from theses and dissertations. We used the methods of classification considering mean and standard deviation, and considering median and pseudo-sigma. The two methods showed similar results so both can be used to classify CV%. We propose only three categories to rank CV%: low, medium and high.

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