Management of Astigmatism in Cataract

Abstract

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

Incisional correction of corneal astigmatism during ‎phacoemulsification – a randomized trial

“…OCCIs are simple to perform, do not require additional skills or instruments, and since the additional incision is self-sealing, particularly when it is not used to introduce instruments, the added risk to the surgery is negligible compared to its benefit of astigmatism reduction. 5,8 The topographic corneal astigmatism in the CCI group decreased by 0.265 AE 0.142 diopters, while OCCI reduced the topographic corneal astigmatism by 0.665 AE 0.268 diopters, which was in agreement with Bhalla's study, which reported a reduction of 0.28 and 0.7 D in topographic astigmatism in CCI and OCCI groups, respectively, 9 but these results were different to other studies.…”

Corneal perforation following arcuate keratotomy in femtosecond laser assisted cataract surgery-a case series

“…Various options available are on-axis corneal incision (OCI), peripheral corneal relaxing incisions (PCRIs) which include manual or limbal relaxing incision (LRI), and Laser assisted PCRIs or arcuate keratotomies (AK), paired opposite clear corneal incision (OCCI), Toric IOLs. 2 , 3 , 4 One of the advantages of FLACS is that the low astigmatism can be corrected with femtosecond laser assisted arcuate keratotomy in the same setting. The Femtosecond laser assisted arcuate keratotomy has been proved to be safe and provides reliable outcomes.…”

Comparative evaluation of two toric intraocular lenses for correcting astigmatism in patients undergoing phacoemulsification

“…There has been a paradigm shift in addressing astigmatism over the years, from methods utilizing neutralization of corneal astigmatism by astigmatic keratotomy and peripheral corneal relaxing incision, the focus has shifted to implantation of toric IOLs as shown in Table 2 . [ 12 ]…”