Corneal astigmatism correction with opposite clear corneal incisions or single clear corneal incision: Comparative analysis

Khokhar, Sudarshan; Lohiya, Pavan; Murugiesan, Vanathi; Panda, Anita

doi:10.1016/j.jcrs.2006.04.010

Cited by 80 publications

(70 citation statements)

References 23 publications

(29 reference statements)

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“…Lever and Dahan reported 33 patients that 3.5 mm opposite clear corneal incisions straddling the steep axis decreased preexisting astigmatism by a mean value of 2 D. 5 Corresponding figures using this method have been reported to be 1.5D by khokhar et al 10 in our study the difference between the preop median and postop median score was 1D.…”

Section: Limbal Relaxing Incisionssupporting

confidence: 68%

Paired Opposite Clear Corneal Incisions to Reduce Preexisting Corneal Astigmatism in Phacoemulsification

Chandrakant¹,

Narayan²,

Srinivasulu³

et al. 2015

jemds

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BACKGROUND:To study the effect of paired opposite clear corneal incisions on the steep axis on preexisting corneal astigmatism in phacoemulsification. MATERIALS AND METHODS:This study was performed on 30 eyes of 30 patients who had keratometric astigmatism of more than 1 diopter. All patients underwent clear corneal phacoemulsification with a 3.2mm clear corneal incision on the steep axis. An additional similar incision was placed on the steep axis opposite to the first incision at the end of surgery. Preoperative keratometric astigmatism was compared with postoperative keratometric astigmatism at 6 weeks postoperatively. RESULTS: The difference between the median score of preoperative keratometric astigmatism and postoperative astigmatism was 1 diopter. Results were analyzed with wilcoxon signed rank test and were significant p value. (<1) CONCLUSION: Paired opposite clear corneal incisions is a simple method to correct mild to moderate corneal astigmatism in phacoemulsification.

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Section: Limbal Relaxing Incisionssupporting

confidence: 68%

Paired Opposite Clear Corneal Incisions to Reduce Preexisting Corneal Astigmatism in Phacoemulsification

Chandrakant¹,

Narayan²,

Srinivasulu³

et al. 2015

jemds

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“…Khokhar et al 12 reported a mean astigmatism correction of 1.66 D at the end of 3 months with OCCI and Nemeth et al reported an astigmatism correction of 1.0 D at the end of 9 weeks with OCCI.…”

mentioning

confidence: 99%

Management of Astigmatism in Cataract

Taneja¹

2015

DJO

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With the recent advances in the instrumentation and intraocular lens (IOL) technology, cataract surgery has, over the past few years, become quite akin to refractive surgery allowing greater control over the patients' refractive and visual outcome. Now the patients expect perfect vision after cataract surgery and surgeons strive hard to deliver the same. In this respect residual astigmatism after cataract surgery is viewed as an undesirable outcome both by the patients and surgeons.In a general cataract population, approximately 10% of patients have astigmatism with greater than 2 D of cylinder, 20% have between 1 and 2 D, and 70% have less than 1 D.1-4 Therefore one may consider treating pre-existing astigmatism in about one out of every three patients. The aim would be to leave the patient with a refractive outcome, for both sphere and cylinder, of 0.50 D or less.However, some surgeons advocate a litt le less aggressive approach to the reduction of residual cylinder as a litt le astigmatism could, in fact, improve uncorrected near vision. Traditionally it has been perceived that residual myopic against the rule cylinder may improve uncorrected near vision. 5In a study conducted recently at our centre, it was seen that myopic astigmatism, up to 1D, in any axis, helps to partially restore uncorrected near visual acuity to some extent but with a proportional loss of distance acuity in pseudophakic eyes with monofocal IOL implant. However, uncorrected myopic astigmatism more than 1 D results in a large loss of distance acuity at no additional benefi t to near acuity. Also, uncorrected hyperopic astigmatism, in any axis, results in deterioration of both distance and near acuities of pseudophakic eyes.6 So a myopic astigmatism less than 1.0 D may be considered benefi cial for near vision by some surgeons, but of doubtful value beyond that.Various

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“…In their series of 33 eyes, mean keratometric astigmatism changed from 2.80 D preoperatively to 0.75 D postoperatively.71 Other studies found similar reductions. 72,73 This method is effective for correction of mild to moderate corneal astigmatism, but in eyes with higher degrees of astigmatism it is recommended to use an alternative method or a combination of two or more methods.74 Disadvantages of this method include the increased risk of endophthalmitis due to the penetrating nature of the incisions as compared to non-penetrating methods. For control of leakage in this method nylon sutures may be used for wound closure.…”

Section: Opposite Side Clear Corneal Incision (Occi)mentioning

confidence: 99%

Surgical Correction of Astigmatism During Cataract Surgery

Çömez¹,

Özkurt²

2012

Astigmatism - Optics, Physiology and Management

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Astigmatism -Optics, Physiology and Management 294Refractive astigmatism; also called total astigmatism; as determined by retinoscopy or by s u b j e c t i v e r e f r a c t i o n , i s m a d e u p o f both corneal and internal astigmatism. Corneal astigmatism occurs due to unequal curvature along the two principal meridians of the anterior cornea and internal astigmatism is due to factors such as the toricity of the posterior surface of the cornea, unequal curvatures of the front and back surfaces of the crystalline lens, or tilting of the crystalline lens with respect to the optic axis of the cornea. The combination of the corneal and the internal astigmatism gives the eye's total(refractive) astigmatism. Corneal astigmatism is often classified according to the axis of astigmatism as being either with-the rule (WTR), oblique or against-the-rule (ATR). It is well accepted that there is some relationship between the eye's corneal and internal astigmatism. In 1890, Javal proposed a rule that predicted the refractive (total) astigmatism of the eye based on the corneal astigmatism.10 Javal's rule states: A t =k + p(A c ) where A t is the refractive (total) astigmatism and A c is the corneal astigmatism. The terms k and p are constants approximated by 0.5 and 1.25, respectively. This rule relies on the fact that residual astigmatism is thought to be constant and ATR in most people (that is, -0.50 D ATR). Keller and colleagues investigated the relationship between corneal and total astigmatism by measuring corneal astigmatism with a computer-assisted videokeratoscope and the results from this study supported Javal's rule.11 To quantify the discrepancy between corneal and refractive astigmatism measurements, the corneal astigmatism value measured by topography or keratometry is substracted from the refractive cylinder measured by wavefront or manifest refraction and the vectorial difference is known as the ocular residual astigmatism (ORA), which is expressed in diopters.12,13 Keratometry, topography, and refraction, all provide useful information regarding the astigmatic status of patients. If the astigmatism measured by these tools is not in agreement either in magnitude, axis, or both, then the surgeon needs to evaluate all the datas again in order to optimise the visual outcome. Corneal topography provides a qualitative and quantitative image map based on evaluation of the corneal curvature14. Most topographers evaluate 8,000 to 10,000 specific points over the entire cornea and center the acquisition on the corneal apex. Topographers that incorporate scanning slit photography also measure the power and the astigmatism of the posterior corneal surface, which may improve correlation with the refractive astigmatism.15 In contrast to topography measurements, manual keratometry has only four data points within 3 mm to 4 mm of the central anterior surface of the cornea. An other device, automated keratometer, although not sensitive for accuracy of axis with low magnitudes of astigmatism, may be useful in screening astig...

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Corneal astigmatism correction with opposite clear corneal incisions or single clear corneal incision: Comparative analysis

Abstract: Paired OCCIs were predictable and effective in providing an enhanced effect for correcting preexisting corneal astigmatism in cataract surgery.

Cited by 80 publications

References 23 publications

Paired Opposite Clear Corneal Incisions to Reduce Preexisting Corneal Astigmatism in Phacoemulsification

Paired Opposite Clear Corneal Incisions to Reduce Preexisting Corneal Astigmatism in Phacoemulsification

Management of Astigmatism in Cataract

Surgical Correction of Astigmatism During Cataract Surgery

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