scholarly journals Effect of 1.8-mm steep-axis clear corneal incision on the posterior corneal astigmatism in candidates for toric IOL implantation

2020 ◽  
Author(s):  
Xi Li ◽  
Xiang Chen ◽  
Suhong He ◽  
Wen Xu
Keyword(s):  
Corneal Astigmatism ◽  
Corneal Incision ◽  
Toric Iol ◽  
Iol Implantation ◽  
Clear Corneal Incision ◽  
Paired T Test ◽  
Anterior Posterior ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

Abstract Background: In the present study, we aimed to analyze the effects of cataract surgery using a 1.8-mm steep-axis clear corneal incision (CCI) on the posterior corneal surfaces based on the keratometry from the rotating Scheimpflug imaging device (Pentacam HR) in candidates for toric intraocular lens (IOL) implantation. Methods: Preoperative and at least 1-month postoperative data measured by Pentacam HR were collected in patients for toric IOL implantation. Surgically induced astigmatism on the posterior cornea (P-SIA) was calculated based on the preoperative and postoperative keratometric data, and the related factors of P-SIA were analyzed. Results: A total of 60 eyes from 56 patients were enrolled. The preoperative anterior, posterior and total corneal astigmatism was 1.58±0.61 D ,0.28±0.22 D and 1.70 ± 0.52 D respectively. The postoperative anterior, posterior and total corneal astigmatism was 1.26±0.68 D, 0.41±0.26 D and 1.30 ± 0.51 D respectively. The astigmatism was significantly decreased on anterior surface (P＜0.001, paired t-test) and increased on posterior surface (P＜0.001, paired t-test). The mean of P-SIA calculated by Holladay–Cravy–Koch method was 0.34±0.20 D, with 0.5 D or greater accounting for 26.7%. A statistically significant correlation was observed between the P-SIA and preoperative anterior corneal astigmatism (r = 0.29, P=0.024), as well as preoperative posterior corneal astigmatism (r=0.27, P=0.038). Multivariate regression analysis showed the preoperative anterior and posterior corneal astigmatism had a significant effect on P-SIA (F=7.344, P=0.001). Conclusions: In candidates for toric IOL implantation with a 1.8-mm steep-axis CCI, the incision caused a significant reduction of the anterior corneal astigmatism but an increase of the posterior corneal astigmatism. P-SIA could not be ignored, and it played a significant role in SIA, especially in cases with higher preoperative anterior or posterior corneal astigmatism.

scholarly journals Effect of 1.8-mm steep-axis clear corneal incision on the posterior corneal astigmatism in candidates for toric IOL implantation

2020 ◽  
Author(s):  
Xi Li ◽  
Xiang Chen ◽  
Suhong He ◽  
Wen Xu
Keyword(s):  
T Test ◽  
Corneal Astigmatism ◽  
Corneal Incision ◽  
Toric Iol ◽  
Iol Implantation ◽  
Clear Corneal Incision ◽  
Significant Difference ◽  
Paired T Test ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism

Abstract PURPOSE In the present study, we aimed to analyze the effects of cataract surgery using a 1.8-mm steep-axis clear corneal incision (CCI) on the posterior corneal surfaces based on the keratometry from the rotating Scheimpflug imaging device (Pentacam HR) in candidates for toric intraocular lens (IOL) implantation. METHODS Preoperative and at least 1-month postoperative data measured by Pentacam HR were collected in patients for toric IOL implantation. Surgically induced astigmatism on the posterior cornea (P-SIA) was calculated based on the preoperative and postoperative keratometric data, and the related factors of P-SIA were analyzed. RESULTS A total of 60 eyes from 56 patients were enrolled. The preoperative anterior and posterior corneal astigmatism was 1.58±0.61 D and 0.28±0.22 D, respectively. The postoperative anterior and posterior corneal astigmatism was 1.26±0.68 D and 0.41±0.26 D, respectively. The astigmatism was significantly decreased on anterior surface (P<0.001, paired t-test) and increased on posterior surface (P<0.001, paired t-test). The mean of P-SIA calculated by Holladay–Cravy–Koch method was 0.34±0.20 D, with 0.5 D or greater accounting for 26.7%. P-SIA showed no significant difference among with-the-rule (WTR) astigmatism, against-the-rule (ATR) astigmatism and oblique astigmatism (F=1.85, P=0.167). A statistically significant correlation was observed between the P-SIA and preoperative anterior corneal astigmatism (r = 0.29, P=0.024), as well as preoperative posterior corneal astigmatism (r=0.27, P=0.038). CONCLUSIONS In candidates for toric IOL implantation with a 1.8-mm steep-axis CCI, the incision caused a significant reduction of the anterior corneal astigmatism but an increase of the corneal posterior astigmatism. P-SIA could not be ignored, and it played a significant role in SIA, especially in cases with higher preoperative anterior or 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 Changes in Anterior, Posterior, and Total Corneal Astigmatism after Descemet Membrane Endothelial Keratoplasty

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Maged Alnawaiseh ◽  
Lars Zumhagen ◽  
André Rosentreter ◽  
Nicole Eter
Keyword(s):  
Corneal Astigmatism ◽  
Endothelial Keratoplasty ◽  
Descemet Membrane Endothelial Keratoplasty ◽  
Axis Orientation ◽  
Descemet Membrane ◽  
Before And After ◽  
Vector Difference ◽  
Anterior Posterior ◽  
Posterior Corneal Astigmatism ◽  
Total Corneal Astigmatism

Purpose. To evaluate changes in anterior, posterior, and total corneal astigmatism in patients after Descemet membrane endothelial keratoplasty (DMEK). Methods. We retrospectively included 29 eyes of 23 patients (age 67.6 ± 9.8 years, 13 female, 10 male) after DMEK surgery. The magnitude and axis orientation of anterior, posterior, and total corneal astigmatism before and after DMEK were determined using a rotating Scheimpflug system (Pentacam HR, Oculus). Results. The magnitude of anterior, posterior, and total corneal astigmatism in the central cornea did not change significantly after surgery. Before surgery, we found a significant correlation between the magnitudes of anterior and posterior corneal astigmatism (Spearman’s correlation coefficient rS=0.526, P=0.003), while after surgery this correlation was no longer significant (rS=0.038, P=0.843). There was a significant correlation between the vector difference between preoperative and postoperative posterior astigmatism and the change in corneal pachymetry (rP=0.47, P=0.010). Conclusions. Posterior corneal astigmatism (especially the orientation) and therefore the relationship between anterior and total corneal astigmatism may change after DMEK. This should be considered to improve the accuracy of toric IOL power calculations following phakic DMEK or in combined procedures.

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.

scholarly journals Clinical differences between toric intraocular lens (IOL) and monofocal intraocular lens (IOL) implantation when myopia is determined as target refraction

2020 ◽  
Author(s):  
Da young Shin ◽  
Ho Sik Hwang ◽  
Hyun Seung Kim ◽  
Man Soo Kim ◽  
Eun Chul Kim
Keyword(s):  
Visual Acuity ◽  
Intraocular Lens ◽  
Corneal Astigmatism ◽  
Spherical Equivalent ◽  
Toric Intraocular Lens ◽  
Toric Iol ◽  
Iol Implantation ◽  
Monofocal Iol ◽  
Target Refraction ◽  
Better Than

Abstract Background: To analyze and compare the clinical results of toric intraocular lens (IOL) and monofocal IOL implantation when the target refraction value is determined -3 diopter (D) in cataract patients with corneal astigmatism >1.5 diopters (D).Methods: We performed a retrospective chart review for patients with corneal astigmatism >1.5D who underwent cataract surgery and their target refraction is determined -3D. 100 eyes (100 patients; monofocal IOL, 60; toric IOL, 40) were enrolled in the current study. Near and distant uncorrected visual acuity (UCVA), corrected VA, spherical equivalent and refractive, corneal astigmatism were evaluated before and after surgery.Results: The near UCVA of the toric IOL group (0.26±0.33) after cataract surgery was significantly better than that of the monofocal IOL group (0.48±0.32) (p=0.030). The distant UCVA of the toric IOL group (0.38 ± 0.14) was also significantly better than that of the monofocal IOL group (0.55 ± 0.22) (p = 0.026). There were no significant intergroup differences in postoperative best-corrected visual acuity (p = 0.710) and mean spherical equivalent (p = 0.465). In the toric IOL group, postoperative refractive astigmatism was -0.80 ± 0.46D and postoperative corneal astigmatism was -1.50 ± 0.62D, whereas the corresponding values in the monofocal IOL group were -1.65 ± 0.77D and -1.45 ± 0.64D; residual refractive astigmatism was significantly lower with toric IOL implantation compared with monofocal IOL implantation (p = 0.001). Conclusions: When myopic refraction such as -3D was determined as the target power in patients with corneal astigmatism, toric IOL implantation led to excellent improvement in both near and distant UCVA.

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
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