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

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

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 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.

scholarly journals Contribution of Posterior Corneal Astigmatism to Total Corneal Astigmatism in a Sample of Egyptian Population

2020 ◽  
Vol Volume 14 ◽  
pp. 3325-3330
Author(s):  
Mohamed Hosny ◽  
Alaa Badawy ◽  
Lobna Khazbak ◽  
Mohamed Anis ◽  
Sarah Azzam
Keyword(s):  
Corneal Astigmatism ◽  
Egyptian Population ◽  
Posterior Corneal Astigmatism ◽  
Total 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 ◽  
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 A New Approach for the Calculation of Total Corneal Astigmatism Considering the Magnitude and Orientation of Posterior Corneal Astigmatism and Thickness

Cornea ◽  
2018 ◽  
Vol 37 (6) ◽  
pp. 720-726 ◽  
Author(s):  
David P. Piñero ◽  
María T. Caballero ◽  
Juan M. Nicolás-Albujer ◽  
Dolores de Fez ◽  
Vicent J. Camps
Keyword(s):  
Corneal Astigmatism ◽  
New Approach ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism
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