scholarly journals Estimation accuracy of surgically induced astigmatism on the cornea when neglecting the posterior corneal surface measurement

2009 ◽  
Vol 89 (5) ◽  
pp. 417-422 ◽  
Author(s):  
Li-Sheng Cheng ◽  
Ching-Yao Tsai ◽  
Ray Jui-Fang Tsai ◽  
Shiow-Wen Liou ◽  
Jau-Der Ho
Keyword(s):  
Surface Measurement ◽  
Estimation Accuracy ◽  
Corneal Surface ◽  
Surgically Induced Astigmatism ◽  
Induced Astigmatism ◽  
Surgically Induced

scholarly journals Comparison of surgically induced astigmatism between anterior and total cornea in 2.2 mm steep meridian incision cataract surgery

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Young-chae Yoon ◽  
Minji Ha ◽  
Woong-Joo Whang
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Corneal Surface ◽  
Polar Plot ◽  
Mean Values ◽  
Surgically Induced Astigmatism ◽  
Induced Astigmatism ◽  
The Mean ◽  
Surgically Induced ◽  
Corneal Refractive Power

Abstract Background This study aimed to compare surgically induced astigmatism (SIA) on the anterior and total cornea during cataract surgery through a 2.2 mm steep meridian incision. Methods The study included 69 left eyes of 69 patients who had undergone cataract surgery. The 69 eyes were classified into three subgroups according to the preoperative steep meridian. Following phacoemulsification, an intraocular lens was inserted into the bag. The keratometric measurements were taken 12 months postoperatively, on the anterior cornea (automated keratometer and anterior keratometry [K] from a rotating Scheimpflug camera) and total cornea (equivalent K reading [EKR] 3.0 mm, EKR 4.5 mm, total corneal refractive power (TCRP) 2.0 mm ring, TCRP 3.0 mm zone, TCRP 4.0 mm zone). The SIA was analyzed for each parameter. Results On the double-angle polar plot, the summated vector mean values of SIA determined by the automated keratometer and Scheimpflug anterior K were 0.28 diopter (axis: 177°) and 0.37 diopter (axis: 175°) in with-the-rule (WTR) astigmatism; 0.03 diopter (axis: 156°) and 0.18 diopter (axis: 177°) in oblique astigmatism; 0.15 diopter (axis: 96°) and 0.17 diopter (axis: 73°) in against-the-rule (ATR) astigmatism. The mean SIAs on the total cornea ranged from 0.31 to 0.42 diopter in WTR astigmatism; from 0.16 to 0.27 diopter in oblique astigmatism; from 0.04 to 0.11 diopter in ATR astigmatism. Mean magnitude SIA ranged from 0.41 to 0.46 diopter on anterior corneal surface and 0.50 to 0.62 diopter on total cornea. J0 and J45 of the posterior cornea showed no significant changes after cataract surgery, and the changes in J0 and J45 did not show any statistical differences between the anterior and total cornea (all p > 0.05). Conclusions There were no differences in the summed vector mean values of SIA between the anterior cornea and the total cornea.

scholarly journals Posterior Corneal Asphericity Effect on Postoperative Astigmatism after EDOF Intraocular Lens Implantation in Cataract Patients

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Mark Rabinovich ◽  
Ivo Guber ◽  
Laëtitia Jessy Niegowski ◽  
Ana Maria Aramburu del Boz ◽  
Danial Al Khatib ◽  
...  
Keyword(s):  
Anterior Chamber Depth ◽  
Q Value ◽  
Corneal Surface ◽  
Surgically Induced Astigmatism ◽  
Postoperative Astigmatism ◽  
Corneal Asphericity ◽  
Induced Astigmatism ◽  
The Impact ◽  
Surgically Induced ◽  
Cataract Patients

Aim. To assess the impact of posterior corneal asphericity on postoperative astigmatism. Methods. We included retrospectively 70 eyes of 70 patients that underwent cataract surgery. We included data of the Q value, Kmax, K1, K2, astigmatism AL, and ACD. We performed a vectorial analysis to calculate the astigmatic vectors. Results. Seventy eyes were evaluated. 40 eyes were of females (58%) and 30 of males (42%). The average cohort age was 73 ± 8.9 years. Axial length (AL) was 23.5 ± 0.9, anterior chamber depth (ACD) was 3.13 ± 0.3, and the average posterior Q value was −0.35 ± 0.2. The only significant predictive variable for the correction index (CI) was the posterior Q value (r = 0.24, p  < 0.05) and for the surgically induced astigmatism (SIA) (β = 0.34, r = 0.58, p  < 0.05). Conclusion. Posterior corneal surface asphericity significantly influences the surgically induced astigmatism and the overcorrection for cataract patients after Lucidis EDOF IOL implantation.

scholarly journals Polar Value Analysis of Low to Moderate Astigmatism with Wavefront-Guided Sub-Bowman Keratomileusis

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Pisong Yan ◽  
Zhiyu Du ◽  
Yu Zhang
Keyword(s):  
Corneal Astigmatism ◽  
Corneal Surface ◽  
Value Analysis ◽  
Surgically Induced Astigmatism ◽  
Induced Astigmatism ◽  
A Minor ◽  
Surgically Induced ◽  
Myopic Astigmatism ◽  
Anterior Corneal Astigmatism ◽  
Posterior Corneal Astigmatism

Purpose. To evaluate the astigmatic outcomes of wavefront-guided sub-Bowman keratomileusis (WFG-SBK) for low to moderate myopic astigmatism.Methods. This study enrolled 100 right eyes from 100 patients who underwent WFG-SBK for the correction of myopia and astigmatism. The polar value method was performed with anterior and posterior corneal astigmatism measured with Scheimpflug camera combined with Placido corneal topography (Sirius, CSO) and refractive astigmatism preoperatively and 1 month, 3 months, and 6 months postoperatively.Results. Similar results for surgically induced astigmatism (SIA) and error of the procedure in both anterior corneal astigmatism (ACA) and total ocular astigmatism (TOA). There was a minor undercorrection of the cylinder in both ACA and TOA. Posterior corneal astigmatism (PCA) showed no significant change.Conclusions. Wavefront-guided SBK could provide good astigmatic outcomes for the correction of low to moderate myopic astigmatism. The surgical effects were largely attributed to the astigmatic correction of the anterior corneal surface. Posterior corneal astigmatism remained unchanged even after WFG-SBK for myopic astigmatism. Polar value analysis can be used to guide adjustments to the treatment cylinder alongside a nomogram designed to optimize postoperative astigmatic outcomes in myopic WFG-SBK.

scholarly journals Corneal Surface Irregularity and Surgically Induced Astigmatism Changes in the Small Incision Versus Microincision After SMILE

2020 ◽  
Author(s):  
Junjie Piao ◽  
Ying Li ◽  
Meng Wang
Keyword(s):  
Biomechanical Properties ◽  
Surface Irregularity ◽  
Corneal Surface ◽  
Surgically Induced Astigmatism ◽  
Small Incision ◽  
Incision Size ◽  
Surface Irregularities ◽  
Induced Astigmatism ◽  
Surgically Induced

Abstract Background: To evaluate the corneal surface irregularity and surgically induced astigmatism changes in the small incision versus microincision after small incision lenticule extraction (SMILE) surgery.Methods: A total of 70 eyes of 35 patients with myopia who underwent SMILE surgery were enrolled in this retrospective study. Patients were divided into two groups according to the incision size (small incision, 4.0 mm or microincision, <2.5 mm) and subjected to a standard ophthalmologic examination preoperatively. The changes in corneal topographic and surface irregularities were evaluated using a TMS-4N topographer during a 6-month follow-up period.Results: According to Friedman’s ANOVA test, there were statistically significant changed in SRI, SAI, and IOP between two groups during a 6-month follow-up (all p < 0.001). At last follow-up, SRI values less than 0.50 D were shown 27 eyes (75%) in the small incision group and 28 eyes (82%) in the microincision group; SAI values less than 0.50 D were shown 22 eyes (61%) in the small incision group and 18 eyes (53%) in the microincision group (all p<0.001).Conclusions: SMILE procedures, using both small incisions and microincisions, are safe and effective surgical options for patients with low to high myopia and provide stable postoperative biomechanical properties and superior postoperative visual outcomes.

scholarly journals Surgically induced astigmatism and coupling effect-mediated keratometric changes after conventional phacoemulsification cataract surgery

2021 ◽  
Author(s):  
Reinhard Angermann ◽  
Christoph Palme ◽  
Philipp Segnitz ◽  
Andreas Dimmer ◽  
Eduard Schmid ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Coupling Effect ◽  
Case Series ◽  
Corneal Incision ◽  
Surgically Induced Astigmatism ◽  
Incision Size ◽  
Case Series Study ◽  
Induced Astigmatism ◽  
Surgically Induced ◽  
Phacoemulsification Cataract Surgery

Summary Background The aim of the present study was to describe surgically induced astigmatism (SIA) and the coupling effect after conventional phacoemulsification cataract surgery (CPS) in relation to the incisional axis. Material and methods A total of 42 patients were included in the retrospective case series study. Corneal topography was obtained for patients with significant cataract before and 6 weeks after CPS with a main clear corneal incision size of 2.4 mm. Patients were grouped according to the relationship of the incisional axis to the position of the steep axis into a steep incisional group and a flat incisional group. Results In total, 46 eyes were included in the study. While the steep incisional group showed an SIA of −0.15 D (± 0.35), the flat incisional group had a significantly higher SIA of 0.20 D (± 0.51) (p = 0.03). The coupling ratio (CR) in the steep incisional group was −0.38 (± 1.41) and in the flat incisional group it was 0.16 (± 0.97). Correspondingly, a coupling constant (CC) of −0.25 was found for group 1 and a CC of 0.0 for group 2. Conclusion Our results suggest that the location of the main incision should be decided with consideration of the corneal astigmatism in order to minimize the SIA. The CR helps to understand the effect of induced astigmatism and the change in spherical equivalent.

scholarly journals Astigmatism Correction during Femtosecond Laser-assisted Transepithelial Arcuate Keratotomy Using the Wound Open Method

2021 ◽  
Vol 62 (12) ◽  
pp. 1592-1599
Author(s):  
Joon Kyo Chung ◽  
Gyu Le Han ◽  
Hoon Noh ◽  
Dong Hui Lim ◽  
Tae-Young Chung
Keyword(s):  
Femtosecond Laser ◽  
Medical Center ◽  
Corneal Astigmatism ◽  
Retrospective Survey ◽  
Surgically Induced Astigmatism ◽  
Open Method ◽  
Astigmatism Correction ◽  
Before And After ◽  
Induced Astigmatism ◽  
Surgically Induced

Purpose: The purpose of this study was to compare corneal astigmatism correction between “wound open” and “wound intact” methods during femtosecond laser-assisted transepithelial arcuate keratotomy.Methods: From April 2016 to December 2018, a retrospective survey was conducted on patients undergoing femtosecond laser cataract surgery at the Ophthalmology Department of Samsung Medical Center. Size comparison and vector analysis of corneal astigmatism before and after surgery were performed in the wound open and wound intact groups.Results: In the wound open and wound intact groups, the target-induced astigmatism (TIA) was 1.28 ± 0.55; and 1.26 ± 0.29 diopters, the surgically induced astigmatism (SIA) was 0.80 ± 0.52; and 0.53 ± 0.32 diopters, and the correction index (CI) was 0.63 ± 0.28; and 0.43 ± 0.26, respectively. The astigmatism correction was superior in the wound open group (p = 0.048, p = 0.025). In a subgroup with TIA < 1.2 diopters, there were no significant differences in SIA or CI between the two groups; however, in the subgroup with a TIA > 1.2 diopters, the SIA was 1.09 ± 0.59; and 0.54 ± 0.37 diopters and the CI was 0.60 ± 0.28; and 0.36 ± 0.23 in the wound open and wound intact groups, respectively (p = 0.022, p = 0.047). Thus, astigmatism correction was superior in the wound open group.Conclusions: The wound open method during femtosecond laser-assisted transepithelial arcuate keratotomy was superior for astigmatism correction compared to the wound intact method.

scholarly journals Comparative study between conventional extra capsular cataract extraction versus manual small incision cataract surgery

2017 ◽  
Vol 5 (3) ◽  
pp. 996 ◽  
Author(s):  
Gannaram Laxmiprasad ◽  
Chhaya Shori ◽  
Rakesh Shori ◽  
Ashalatha Alli
Keyword(s):  
Cataract Surgery ◽  
Tertiary Care ◽  
Posterior Chamber ◽  
Small Incision Cataract Surgery ◽  
Visual Rehabilitation ◽  
Surgically Induced Astigmatism ◽  
Small Incision ◽  
Significant Difference ◽  
Induced Astigmatism ◽  
Surgically Induced

Background: Recent reports indicate that both manual small incision cataract surgery and extra capsular cataract excision surgery with posterior chamber intraocular lens implantation are safe and effective for treatment of cataract surgery, however, manual small incision cataract surgery gives better uncorrected vision. Objectives of the study were to compare intraoperative and postoperative complications, to compare induced astigmatism and to compare the visual rehabilitation.Methods: This is a prospective study of 100 consecutive patients assigned to undergo conventional extra capsular cataract excision surgery (50 cases) and manual small incision cataract surgery (50 cases). Study was done for a period of two years at a tertiary care referral hospital. Institutional Ethics Committee permission was taken. Also the informed consent was obtained from each patient.Results: In conventional ECCE, the most common surgically induced astigmatism was WTR in 73.4% of cases with mean of 2.79 D±1.3 on first day. 70% of cases with mean 2.1 D±1.28 and 64% of cases with mean of 1.86 D±1.14 at six weeks. ATR was common in MSICS group, 83.67% of cases with mean of 1.5 D±0.72 on first day, 86% of cases with mean of 1.03 D±0.6 at one week and 88% of cases with mean of 1.27 D±0.81 at six weeks. The induced astigmatism was less in MSICS group compared to ECCE group at first day but after six weeks there was no much significant difference found. Early visual recovery was better in MSICS groupConclusions: MSICS has definitive advantages over conventional ECCE in terms of early visual rehabilitation, minimal surgically induced astigmatism; no suture related complications and reduced surgical time.

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