Incisional correction of corneal astigmatism during ‎phacoemulsification – a randomized trial

Najah K Mohammad,Tamer F Elewa,Enas B Aldehaimy,Tareq A Almamoun

doi:10.12688/f1000research.54169.1

Najah K Mohammad, Tamer F Elewa + Show 2 more

Open Access

https://doi.org/10.12688/f1000research.54169.1

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Abstract

Background: Phacoemulsification is regarded as a type of refractive surgery by which it is possible to ‎reduce pre-existing corneal stigmatism.‎ This study aimed to evaluate the efficacy and safety of on-axis corneal incision with or without opposite clear corneal incisions (OCCI) to correct preoperative corneal astigmatism during uncomplicated phacoemulsification ‎surgeries.‎ Methods: A randomized, prospective, parallel two-arm interventional study, which included a ‎total 40 eyes from 40 patients, was conducted.‎ Patients were divided into two groups: 20 patients as controls underwent phacoemulsification with on-axis incision (CCI group), and 20 patients underwent phacoemulsification with OCCI (OCCI group). Results: Mean astigmatic correction was significantly higher in the OCCI group (0.665 vs 0.265 diopters, p-value <0.001), compared to the CCI group. Most of the parameters (surgical induced astigmatism, magnitude of error, and correction index) were significantly higher in the OCCI group compared to the CCI group (p-value <0.01). There were no ‎incision-related complications. Conclusions: Both incisional methods are useful methods for correction of preoperative corneal ‎astigmatism but OCCIs correct a higher amount of astigmatism than the on-axis clear ‎corneal incision.‎ Registration: ClinicalTrials.gov NCT04418986 (05/06/2020).

Highlights

Cataract surgery is considered to be a refractive surgery, with the main therapeutic goal of achieving emmetropia; as a result, correction of corneal astigmatism becomes essential for such an operation.[1,2] The prevalence of corneal astigmatism of more than 1 diopter is as high as 45% of those who undergo cataract surgery.[3]It is possible to reduce pre-existing corneal astigmatism by creating a clear corneal incision at the steep meridian of the cornea; astigmatism correction is limited to a maximum of 1 diopter (D) when corrected by a small incision
The mean age of participants was 57.9 Æ 13.25, and 52.5% were males (21/40).[16]. These cases were divided into two groups: CCI and opposite clear corneal incisions (OCCI) groups
Mean corneal power significantly reduced after one month postoperatively in the OCCI group, while the CCI group showed a slight reduction in mean corneal power postoperatively

Summary

Introduction

It is possible to reduce pre-existing corneal astigmatism by creating a clear corneal incision at the steep meridian of the cornea; astigmatism correction is limited to a maximum of 1 diopter (D) when corrected by a small incision. A possible limitation is the difficulty in performing the operation which is caused by the location of the steep meridian, such as the difficulty of creating superonasal or inferonasal incisions at the left eye. This approach is usually sufficient for correcting astigmatism less than 1 D in most eyes.[1,4] An opposite side clear corneal incision (OCCI) could enhance the flattening effect on the cornea.[5].

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