scholarly journals Repeatability and comparability of the Galilei-G4 and Cassini in measuring corneal power and astigmatism in normal and post-refractive surgery eyes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohamed Mohamed ◽  
Mahmood Khan ◽  
Amritha Kanakamedala ◽  
Isha Gupta ◽  
Li Wang ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Intraclass Correlation ◽  
Corneal Astigmatism ◽  
Corneal Power ◽  
History Of ◽  
The Mean ◽  
Age Range ◽  
High Repeatability ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

AbstractTo assess the repeatability and comparability of the Galilei G4 versus the Cassini topographer in post-refractive eyes and in normal eyes, including older patients representative of an initial cataract evaluation. Simulated keratometric (simK), total corneal and posterior corneal power and astigmatism were evaluated in both post-refractive and normal eyes. Repeatability was measured by calculating within-subject standard deviation (Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Vector analyses and Bland–Altman plots were employed to assess agreement between devices. We studied 32 subjects with a history of refractive surgery and 32 subjects without a history of refractive surgery undergoing cataract surgery. The mean age was 55 ± 18.5 years and the age range was 21.5–91.5 years. In non-refractive and post-refractive eyes, the ICC was > 0.9 (P < 0.001) for all corneal powers and for simK and total corneal astigmatism for both analyzers. The ICC for posterior corneal astigmatism magnitude using the Galilei was 0.62 and 0.67 and for the Cassini 0.55 and 0.38 in normal and post-refractive eyes, respectively. In both post-refractive and normal eyes, the Galilei G4 and Cassini analyzers have high repeatability in simK, total, and posterior corneal power and low repeatability for posterior corneal astigmatism.

scholarly journals Repeatability and Comparability of the Galilei-G4 and Cassini in Measuring Corneal Power and Astigmatism in Normal and Post-Refractive Surgery Eyes

2021 ◽  
Author(s):  
Mohamed Mohamed ◽  
Mahmood Khan ◽  
Amritha Kanakamedala ◽  
Isha Gupta ◽  
Li Wang ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Intraclass Correlation ◽  
Corneal Astigmatism ◽  
Corneal Power ◽  
History Of ◽  
The Mean ◽  
Age Range ◽  
High Repeatability ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

Abstract PURPOSE To assess the repeatability and comparability of the Galilei G4 versus the Cassini topographer in post-refractive eyes and in normal eyes, including older patients representative of an initial cataract evaluation. METHODS Simulated keratometric (simK), total corneal and posterior corneal power and astigmatism were evaluated in both post-refractive and normal eyes. Repeatability was measured by calculating within-subject standard deviation (Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Vector analyses and Bland-Altman plots were employed to assess agreement between devices. RESULTS We studied 32 subjects with a history of refractive surgery and 32 subjects without a history of refractive surgery undergoing cataract surgery. The mean age was 55 ± 18.5 years and the age range was 21.5 to 91.5 years. In non-refractive and post-refractive eyes, the ICC was > 0.9 (P < .001) for all corneal powers and for simK and total corneal astigmatism for both analyzers. The ICC for posterior corneal astigmatism magnitude using the Galilei was 0.62 and 0.67 and for the Cassini 0.55 and 0.38 in normal and post-refractive eyes, respectively. CONCLUSIONS In both post-refractive and normal eyes, the Galilei G4 and Cassini analyzers have high repeatability in simK, total, and posterior corneal power and low repeatability for posterior corneal astigmatism.

scholarly journals Does pterygium morphology affect corneal astigmatism?

2021 ◽  
Vol 13 ◽  
pp. 251584142110304
Author(s):  
Emine Doğan ◽  
Burçin Çakır ◽  
Nilgün Aksoy ◽  
Elif Köse ◽  
Gürsoy Alagöz
Keyword(s):  
Anterior Segment ◽  
Clinical Information ◽  
Corneal Astigmatism ◽  
Continuous Group ◽  
Optic Coherence Tomography ◽  
Morphological Pattern ◽  
Horizontal Length ◽  
The Mean ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism

Purpose: The purpose of this study was to evaluate the correlation between corneal astigmatism and the morphology of pterygium with anterior segment optic coherence tomography (AS-OCT). Material and Methods: The size of pterygium (horizontal length, vertical width) was measured manually; pterygium area and percentage extension of the pterygium onto the cornea were calculated. Anterior and posterior corneal astigmatism, Sim K, K1, K2 were measured using a dual Scheimpflug analyzer. Morphological patterns of the pterygium analyzed with AS-OCT were determined according to the extension of the pterygium apex below the corneal epithelium. Two tomographic patterns were identified: continuous and nodular. Correlation between anterior corneal astigmatism and pterygium size, percentage extension of the pterygium, and morphological pattern of the pterygium was analyzed. Results: The mean ages of the 47 patients were 49.4 ± 16.6 (22–80) years. Mean horizontal pterygium length, vertical width, pterygium area, and percentage extension of the pterygium were 2.8 ± 1.2 mm, 4.8 ± 1.6 mm, 7.42 ± 5.6 mm2 and 24.5 ± 10.4%, respectively. Mean anterior corneal astigmatism was 2.3 ± 2.3 D and simulated keratometry was 43.4 ± 2.02 D. In terms of the morphological pattern of the pterygium, 24 eyes had continuous, 23 eyes had a nodular pattern and the median (interquartile range) anterior corneal astigmatism was 1.87 (1.01–3.80) and 1.22 D (0.58–2.35), respectively ( p = 0.102). Other topographic and pterygium size parameters were similar between groups. Analyzing the correlations in groups separately, a positive moderate statistically significant correlation was present between vertical width, percentage extension, pterygium area, and anterior corneal astigmatism in both continuous and nodular groups. Conclusions: Although not statistically significant, anterior corneal astigmatism was higher in continuous group. Using AS-OCT to standardize the morphology of pterygium could provide additional clinical information.

Significance of dynamic contour tonometry in evaluation of progression of glaucoma in patients with a history of laser refractive surgery

2019 ◽  
Vol 104 (2) ◽  
pp. 276-281 ◽  
Author(s):  
Sang Yeop Lee ◽  
Eun Woo Kim ◽  
Wungrak Choi ◽  
Chan Keum Park ◽  
Sangah Kim ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Open Angle Glaucoma ◽  
Corneal Thickness ◽  
Significant Risk ◽  
Applanation Tonometry ◽  
Dynamic Contour Tonometry ◽  
Significant Difference ◽  
History Of ◽  
The Mean ◽  
Laser Refractive Surgery

AimsIn this study, we tested the hypothesis that intraocular pressure (IOP) parameters measured by dynamic contour tonometry (DCT) would be more relevant in progression of glaucoma when there is a history of laser refractive surgery (LRS) than the IOP parameters measured by Goldmann applanation tonometry (GAT) or calculated by correction formulae.MethodsNinety-eight eyes in 54 patients with open-angle glaucoma and a history of LRS were included in this retrospective study. IOP was measured by both GAT and DCT during follow-up. Baseline, mean, and peak IOP, IOP fluctuation, and IOP reduction were measured by each tonometry method. Corrected IOP parameters using central corneal thickness and mean keratometry values were also analysed. Clustered logistic regression was used to identify variables correlated with progression of glaucoma. Areas under the curve (AUCs) for correlated variables were also compared.ResultsThe mean DCT value (OR 1.36, p=0.024), peak DCT value (OR 1.19, p=0.02) and pattern SD (OR 1.10, p=0.016) were significant risk factors for progression. There was a significant difference in the predictive ability of the mean DCT and GAT values (AUC 0.63 and 0.514, respectively; p=0.01) and of the peak DCT and GAT values (0.646 and 0.503, respectively, p=0.009). The AUCs for corrected IOP did not exceed those of DCT.ConclusionsIOP measurements were more associated with progression of glaucoma when measurements were obtained by DCT than by GAT or correction formulae in eyes with a history of LRS.

Posterior corneal astigmatism modifications after cataract surgery and its role on total corneal astigmatism

2018 ◽  
Vol 3 ◽  
pp. 40-40
Author(s):  
Diana Silva ◽  
Mafalda Mota ◽  
Catarina Pedrosa ◽  
Peter Pêgo ◽  
Sara Pinto ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Corneal Astigmatism ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

Contribution of posterior corneal astigmatism to total corneal astigmatism

2012 ◽  
Vol 38 (12) ◽  
pp. 2080-2087 ◽  
Author(s):  
Douglas D. Koch ◽  
Shazia F. Ali ◽  
Mitchell P. Weikert ◽  
Mariko Shirayama ◽  
Richard Jenkins ◽  
...  
Keyword(s):  
Corneal Astigmatism ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

scholarly journals Acceleration of 2D-MR fingerprinting by reducing the number of echoes with increased in-plane resolution: a volunteer study

2020 ◽  
Vol 33 (6) ◽  
pp. 783-791
Author(s):  
Yusuke Yokota ◽  
Tomohisa Okada ◽  
Yasutaka Fushimi ◽  
Akira Yamamoto ◽  
Satoshi Nakajima ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Region Of Interest ◽  
Intraclass Correlation Coefficients ◽  
Coefficients Of Variation ◽  
Volunteer Study ◽  
The Mean ◽  
T1 And T2 ◽  
High Repeatability ◽  
Measurement Repeatability

Abstract Objective To compare the absolute values and repeatability of magnetic resonance fingerprinting (MRF) with 3000 and 1500 echoes/slice acquired in 41 s and 20 s (MRF3k and MRF1.5k, respectively). Materials and methods MRF3k and MRF1.5k scans based on fast imaging with steady precession (FISP) were conducted using a 3 T scanner. Inter-scan agreement and intra-scan repeatability were investigated in 41 and 28 subjects, respectively. Region-of-interest (ROI) analysis was conducted on T1 values of MRF3k by two raters, and their agreement was evaluated using intraclass correlation coefficients (ICCs). Between MRF3k and MRF1.5k, differences in T1 and T2 values and inter-measurement correlation coefficients (CCs) were investigated. Intra-measurement repeatability was evaluated using coefficients of variation (CVs). A p value < 0.05 was considered statistically significant. Results The ICCs of ROI measurements were 0.77–0.96. Differences were observed between the two MRF scans, but the CCs of the overall ROIs were 0.99 and 0.97 for the T1 and T2 values, respectively. The mean and median CVs of repeatability were equal to or less than 1.58% and 3.13% in each of the ROIs for T1 and T2, respectively; there were some significant differences between MRF3k and MRF1.5k, but they were small, measuring less than 1%. Discussion Both MRF3k and MRF1.5k had high repeatability, and a strong to very strong correlation was observed, with a trend toward slightly higher values in MRF1.5k.

scholarly journals Distribution and internal correlations of corneal astigmatism in cataract patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuanfeng Jiang ◽  
Ying Qin ◽  
Shaochong Bu ◽  
Hong Zhang ◽  
Xiaomin Zhang ◽  
...  
Keyword(s):  
Distribution Patterns ◽  
Corneal Astigmatism ◽  
Morphological Parameters ◽  
Summation Effect ◽  
Age Related ◽  
Cataract Patients ◽  
Age Related Changes ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

AbstractThe aim of the study is to explore the distribution patterns and internal correlations of the morphological parameters of the cornea in patients with age-related cataract. The Pentacam HR was used to measure anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), total corneal astigmatism (TCA) and keratometric corneal astigmatism (KCA). With age, the proportion of with-the-rule (WTR) ACA decreased from 65.31% to 23.63%, while the against-the-rule (ATR) ACA increased from 26.53% to 56.20%. PCA exceeded 0.50 D in 9.14% of eyes, while 76.35% of them were ATR. The magnitude of ACA was positively correlated with PCA in the whole sample, with a more significant correlation in WTR eyes (sr = 0.349, P < 0.001). The vector summation effect of PCA to ACA changed from compensation to augmentation with aging. In 57.53% of WTR eyes, KCA was overestimated by an average of 0.21 ± 0.17 D, while it was underestimated by 0.38 ± 0.27 D in 87.62% of ATR eyes. In conclusion, among age-related cataract patients, ACA and TCA gradually shifted from WTR to ATR with aging, while most PCA remained as ATR. Ignoring the age-related changes and real PCA might cause overestimation of WTR astigmatism and underestimation of ATR astigmatism.

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