Incisional Correction of Corneal Astigmatism During Phacoemulsification

Today, cataract surgery is regarded as refractive surgery, mainly aiming emmetropia, and this makes eliminating corneal astigmatism is critical. Corneal astigmatism of more than 1 diopter has been reported in up to 45% of the cataract surgery candidates. It is possible to reduce pre-existing corneal astigmatism by creating a clear corneal incision at the steep meridian of the cornea, however; creating a small incision can correct the only astigmatism up to 1 Diopter, and sometimes this method may not be easy to perform due to the location of steep meridian like the difficulty while creating a superonasal or inferonasal incision at the left eye. This approach is usually sufficient for correcting astigmatism less than 1 D in most eyes. An opposite side clear corneal incision (OCCI) could enhance the flattening effect on the cornea.

A randomized, parallel two-arm interventional study, the patients were divided into a 1:1 ratio, the study included eyes with visually significant cataract and preoperative corneal regular astigmatism between 0.75 and 2 Diopters undergoing phacoemulsification surgery. They were divided into two groups: controls underwent phacoemulsification with on-axis incision (CCI Group), and patients underwent phacoemulsification with opposite clear corneal incisions (OCCI Group).

Coaxial small incision cataract surgery was performed for all cases using a 2.8 mm keratome placed at steep meridian and 1-mm paracentesis was made 90 degrees apart with a 20-gauge microvitrectomy blade. Surgery was performed with a 30-degree, 0.9-caliper phacoemulsification tip (microtip) with a divide and conquer technique. In the OCCI group, a single penetrating incision was created with 2.8 mm keratome in the clear cornea, 1.5 mm anterior to limbal blood vessels, centered over the steep meridian and opposite the phacoemulsification incision.

Inclusion Criteria: Clear cornea No history of previous ocular surgery Central corneal thickness (CCT) <640 Exclusion Criteria: Irregular corneal astigmatism or lenticular astigmatism Corneal opacities or pathology like Fuch's endothelial dystrophy Previous ocular surgeries like glaucoma surgery or PKP or pterygium excision Posterior segment diseases and pathology Complicated phacoemulsification