Effect of Corneal Incision Enlargement on Surgically Induced Astigmatism in Biaxial Microincision 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.

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Site of clear corneal incision in cataract surgery and its effects on surgically induced astigmatism

Scientific Reports ◽

10.1038/s41598-020-60985-5 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Junjie Piao ◽

Choun-Ki Joo

Keyword(s):

Cataract Surgery ◽

Corneal Incision ◽

Surgically Induced Astigmatism ◽

Clear Corneal Incision ◽

Induced Astigmatism ◽

Surgically Induced

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Minimizing Surgically Induced Astigmatism at the Time of Cataract Surgery Using a Square Posterior Limbal Incision

Journal of Ophthalmology ◽

10.1155/2011/243170 ◽

2011 ◽

Vol 2011 ◽

pp. 1-4 ◽

Cited By ~ 7

Author(s):

Paul Ernest ◽

Warren Hill ◽

Richard Potvin

Keyword(s):

Cataract Surgery ◽

Corneal Astigmatism ◽

Intraocular Lenses ◽

Corneal Incision ◽

Surgically Induced Astigmatism ◽

Clear Corneal Incision ◽

Refractive Outcomes ◽

Induced Astigmatism ◽

Surgically Induced ◽

Corneal Incisions

Purpose. To compare the surgically induced astigmatism from clear corneal and square posterior limbal incisions at the time of cataract surgery.Methods. Surgically induced astigmatism was calculated for a set of eyes after cataract surgery using a temporal 2.2 mm square posterior limbal incision. Results were compared to similar available data from surgeons using clear corneal incisions of similar size.Results. Preoperative corneal astigmatism averaged 1.0 D and was not significantly different between the incision types. Surgically induced astigmatism with the 2.2 mm posterior limbal incision averaged0.25±0.14 D, significantly lower in magnitude than the aggregate surgically induced astigmatism produced by the 2.2 mm clear corneal incision (0.68±0.49 D).Conclusion. The 2.2 mm square posterior limbal incision induced significantly less, and significantly less variable, surgically induced astigmatism relative to a similar-sized clear corneal incision. This is likely to improve refractive outcomes, particularly important with regard to premium intraocular lenses.

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A STUDY ON COMPARISON OF KERATOMETRIC CHANGES BETWEEN PREINCISION AND SINGLE-STEPPED CLEAR CORNEAL INCISION IN PHACOEMULSIFICATION SURGERY

10.36106/ijsr/8403119 ◽

2021 ◽

pp. 4-5

Author(s):

Sourav Kumar Das ◽

Aritro Nandi ◽

Rupam Datta ◽

Debarshi Jana

Keyword(s):

Cataract Surgery ◽

West Bengal ◽

Corneal Incision ◽

Surgically Induced Astigmatism ◽

Medical College ◽

Clear Corneal Incision ◽

Lens Implantation ◽

Induced Astigmatism ◽

Surgically Induced ◽

Corneal Incisions

Phacoemulsication surgery is the most widely used technique for cataract surgery nowadays. It can be done by either pre-incision or by clear corneal incisions. Clear corneal incisions are becoming more popular option for cataract surgery and IOL (intraocular lens) implantation. The availability of foldable IOL that can be inserted through small incisions has created a trend for clear corneal incisions. To compare post-operative kera to metric changes after phacoemulsication surgery between pre-incision or tunnel-based incision and single stepped clear corneal incisions. Fifty patients undergoing phacoemulsication surgery in the Dept. Of Ophthalmology, Nilratan Sircar Medical College & Hospital, Kolkata, West Bengal. Both pre-incision and clear-corneal incision in phacoemulsication surgery results in surgically induced astigmatism post-operatively, but there was no signicant difference in post-operative induced astigmatism in between both techniques.

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Effect of femtosecond laser-assisted steepest-meridian clear corneal incisions on preexisting corneal regular astigmatism at the time of cataract surgery

International Journal of Ophthalmology ◽

10.18240/ijo.2020.12.08 ◽

2020 ◽

Vol 13 (12) ◽

pp. 1895-1900

Author(s):

Wei Chen ◽

Jian Wu ◽

Yong Wang ◽

Jing Zhou ◽

Rong-Rong Zhu ◽

...

Keyword(s):

Femtosecond Laser ◽

Cataract Surgery ◽

Corneal Astigmatism ◽

Corneal Incision ◽

Surgically Induced Astigmatism ◽

Clear Corneal Incision ◽

Case Series Study ◽

Induced Astigmatism ◽

Surgically Induced ◽

Corneal Incisions

AIM: To investigate the clinical efficacy and safety of femtosecond laser-assisted steepest-meridian clear corneal incisions for correcting preexisting corneal astigmatism performed at the time of cataract surgery. METHODS: This prospective case series study comprised consecutive age-related cataract patients with corneal regular astigmatism (range: +0.75 to +2.50 D) who had femtosecond laser-assisted steepest-meridian clear corneal incisions (single or paired). Corneal astigmatism was performed with the Pentacam preoperatively and 3mo postoperatively. Total corneal astigmatism and steepest-meridian measured in the 3-mm central zone were used to guide the location, size and number of clear corneal incision. The vector analysis of astigmatic change was performed using the Alpins method. RESULTS: Totally 138 eyes of 138 patients were included. The mean preoperative corneal astigmatism was 1.31±0.41 D, and was significantly reduced to 0.69±0.34 D (equivalent to difference vector) after surgery (P<0.01). The surgically-induced astigmatism was 1.02±0.54 D. The correction index (ratio of target induced astigmatism and surgically-induced astigmatism: 0.72±0.36) as well as the magnitude of error (difference between surgically-induced astigmatism and target induced astigmatism: -0.29±0.51) represented a slight under correction. For angle of error, the arithmetic mean was 1.11±13.70, indicating no significant systematic alignment errors. CONCLUSION: Femtosecond-assisted steepest-meridian clear corneal incision is a fast, customizable, adjustable, precise, and safe technique for the reduction of low to moderate corneal astigmatism during cataract surgery.

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Comparison of Mean and Centroid of Surgically Induced Astigmatism After Standard Cataract Surgery

Frontiers in Medicine ◽

10.3389/fmed.2021.670337 ◽

2021 ◽

Vol 8 ◽

Author(s):

Kazutaka Kamiya ◽

Kei Iijima ◽

Wakako Ando ◽

Nobuyuki Shoji

Keyword(s):

Cataract Surgery ◽

Arithmetic Mean ◽

Corneal Astigmatism ◽

Corneal Incision ◽

Surgically Induced Astigmatism ◽

Clear Corneal Incision ◽

Induced Astigmatism ◽

The Individual ◽

The Right ◽

Surgically Induced

Purpose: To compare the arithmetic mean of surgically induced astigmatism (M-SIA) and the centroid of surgically induced astigmatism (C-SIA) after standard cataract surgery.Methods: We retrospectively examined 200 eyes of 100 consecutive patients undergoing bilateral cataract surgery through a 2.8 mm temporal clear corneal incision. We quantitatively measured the magnitude and axis of corneal astigmatism preoperatively and 3 months postoperatively using an automated keratometer (TONOREFF-II, Nidek). We assessed the M-SIA, the C-SIA, and the double angle plots for the display of the individual SIA distributions.Results: For bilateral data analysis, the magnitude of corneal astigmatism significantly increased from 0.66 ± 0.39 D preoperatively to 0.74 ± 0.46 D postoperatively (paired t-test, p = 0.012). The M-SIA was 0.50 ± 0.36 D. On the other hand, the C-SIA was 0.18 ± 0.60 D at an axis of 97°. For unilateral analysis, we obtained similar outcomes between the right and left eye groups.Conclusions: According to our experience, standard cataract surgery induces the M-SIA by approximately 0.5 D. The magnitude of the C-SIA largely decreased to approximately 40% of the M-SIA, and the direction of the C-SIA showed a tendency toward with-the-rule astigmatism. It should be noted that the M-SIA was considerably different from the C-SIA, especially when selecting the appropriate toric IOL model and power.

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

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20170650 ◽

2017 ◽

Vol 5 (3) ◽

pp. 996 ◽

Cited By ~ 1

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

BMC Ophthalmology ◽

10.1186/s12886-021-02131-x ◽

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.

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