Surgically induced astigmatism after phacoemulsification by temporal clear corneal and superior clear corneal approach: a comparison

Abstract

IntroductionCataract surgery has undergone various advances since it was evolved from ancient couching to the modern phacoemulsification cataract surgery. Surgically induced astigmatism (SIA) remains one of the most common complications. The introduction of sutureless clear corneal incision has gained increasing popularity worldwide because it offers several advantages over the traditional sutured limbal incision and scleral tunnel. A clear corneal incision has the benefit of being bloodless and having an easy approach, but SIA is still a concern.PurposeIn this study, we evaluated the SIA in clear corneal incisions with temporal approach and superior approach phacoemulsification. Comparisons between the two incisions were done using keratometric readings of preoperative and postoperative refractive status.MethodologyIt was a hospital-based prospective interventional comparative randomized control trial of 261 patients conducted in a rural-based tertiary care center from September 2012 to August 2014. The visual acuity and detailed anterior segment and posterior segment examinations were done and the cataract was graded according to Lens Opacification Classification System II. Patients were divided for phacoemulsification into two groups, group A and group B, who underwent temporal and superior clear corneal approach, respectively. The patients were followed up on day 1, 7, 30, and 90 postoperatively. The parameters recorded were uncorrected visual acuity, best-corrected visual acuity, slit lamp examination, and keratometry. The mean difference of SIA between 30th and 90th day was statistically evaluated using paired t-test, and all the analyses were performed using SPSS 18.0 (SPSS Inc.) software.ResultsThe mean postoperative SIA in group A was 0.998 D on the 30th day, which reduced to 0.768 D after 90 days, and in group B the SIA after 30 days was 1.651 D, whereas it reduced to 1.293 D after 90 days.ConclusionTemporal clear corneal incision is evidently better than superior clear corneal incision as far as SIA is concerned.

One-year follow-up of changes in refraction and aberrations induced by corneal incision

“…In ophthalmologic surgical procedures, mainly with implantation of intraocular lenses, (IOLs), such as cataract surgery and refractive surgery with phakic IOLs, corneal incisions flatten the perpendicular corneal meridian inducing surgically induced astigmatism (SIA) that depends on size[1], location[2,3] and design[4] of the incisions. Currently, the use of injector systems[5] eases the insertion of foldable IOLs through incisions of 3 mm or below, although some rigid phakic IOLs[6] still needs longer incisions of around 6 mm.…”

“…Currently, the use of injector systems[5] eases the insertion of foldable IOLs through incisions of 3 mm or below, although some rigid phakic IOLs[6] still needs longer incisions of around 6 mm. Previous studies have compared the values of SIA with different sizes of incisions[1–3,7–14] and some of them[1–3,9,10,14] have also evaluated the long-term evolution. In follow-ups between 1 week and 1 month after cataract surgery the mean values of SIA are around 0.50, 0.75 and 1.0 for 2, 3 and 5-mm sizes of incisions respectively.…”

Optimization of surgical parameters based on patient-specific models: Application to arcuate keratotomy

“…Although new techniques such as sutureless clear corneal incision have been introduced to replace limbal incisions, cataract interventions frequently induce undesired astigmatism. A recent study reported an average induced astigmatism between 0.77D and 1.29D depending on whether the clear corneal incision was performed with a temporal or superior approach, confirming results from the late nineties of induced astigmatism between 0.62 D and 1.44 D. [1][2] About two-thirds of patients also have a pre-existing astigmatism over 1.0D, [3][4] which also requires some correction to optimize postoperative visual acuity. Thus, cataract surgery has evolved towards refractive surgery that aims to restore spectacle-free vision for the patient.…”

Face and content validation of Phacoemulsification Techniques Related To Surgically Induced Astigmatism questionnaire

“…SIA has been emphasized in previous studies as it leads to better visual performance and satis- (Gundersen and Potvin, 2016;Srivannaboon and Chirapapaisan, 2017;Clark, 2018) . The surgical technique is an established factor that in luences SIA (Kawahara et al, 2013;Kwon et al, 2014;Chang et al, 2015;Nikose et al, 2018) . However, incomplete information on surgical techniques in operative notes could hinder retrospective studies of SIA.…”

“…Surgically induced astigmatism (SIA) in post phacoemulsi ication cataract surgery is determined by the surgical techniques. Several surgical techniques associated with SIA had been discussed in previous studies (Kawahara et al, 2013;Kwon et al, 2014;Chang et al, 2015;Nikose et al, 2018) . Other factors such as the location and size of the main incision are also frequently reported as signi icant factors that are related to the SIA, although not regularly documented in surgical notes.…”