Paired Opposite Clear Corneal Incision in Cataract Patients with Different Types of Astigmatism

Purpose: To compare the refractive effects of paired-opposite clear corneal incision (p-OCCI) with-the-rule (WTR), against-the-rule (ATR) and oblique astigmatism. Methods: This retrospective study was conducted in 131 patients undergoing uneventful cataract surgery.In all cases, a 2.4 mm p-OCCI was made 180 degrees opposite to the meridian of the vertical axis.Preoperative and 6-month postoperative keratometry values obtained from partial coherence interferometry were used to calculate corrected keratometric astigmatism and vectorial analysis parameters were calculated by Alpins method.These parameters were surgically induced astigmatism (SIA), target induced astigmatism (TIA), correction index (CI), angle of error (AE), difference vector (DV), flattening effect (FE). Results: There was no significant difference between the three groups in terms of uncorrected and best corrected visual acuities (p> 0.05).Mean corrected keratometric astigmatism values were 1.06± 0.15 D in WTR astigmatism group, 1.21± 0.35 D in ATR astigmatism group and 1.15± 0.29 D in oblique astigmatism group (p> 0.05).SIA value was 1.15± 0.54 D in WTR astigmatism group, 0.79 ± 0.31 D in ATR astigmatism group and 0.53 ± 0.14 D in oblique astigmatism group (p=0.006).In terms of FE,there was no statistically significant difference between the WTR and oblique astigmatism groups, while it was lowest in the ATR astigmatism group (p> 0.05, p=0.03,respectively).The CI value was similar in the WTR and ATR astigmatism groups, but lower in the oblique astigmatism group (p> 0.05, p=0.04,respectively).There was no significant difference between the three groups in terms of TIA, AE and DV (p> 0.05). Conclusion: Although the corneal astigmatism-correcting effect of p-OCCI is similar in different types of astigmatism,p-OCCI may be less predictable in oblique astigmatism. Keywords: astigmatism, opposite clear corneal incision, cataract, vectorial analysis