Effect Of Different Corneal Incisions On Induced Change Of Corneal Refraction After Phacoemulsification And Intraocular Lens Implantation

Purpose: To evaluate the effect of different 3.2mm clear corneal incisions on induced change of corneal refraction after phacoemulsification and foldable posterior chamber intraocular lens implantation. Methods: In a prospective clinical study, 81 eyes of 63 patients with cataract had phacoemulsification and implantation of a foldable intraocular lens using a 3.2mm unsutured clear corneal incision. 63 patients were divided into three groups randomly: Group A, received temporal clear corneal oblique incision(28 eye of 22 cases);Group B, received superior(l 1:00) clear corneal oblique incision(26 eye of 22 cases); Group C, received superior( 11:00) clear corneal tunnel incision(27 eye of 21 cases). Patients were examined preoperatively and 1 day, Iweek, and 1 and 3 months postoperatively by using slit-lamp microsope and corneal topography, and visual acuity also was performed. Surgically induced astigmatism was calculated by vector analysis.Results: At preoperatively, the mean astigmatism was (0.51±0.27)D in group A, (0.52 ± 0.31)D in group B and (0.50 ± 0.27) D in group C, respectively. At 1 day, Iweek, and 1 and 3 months postoperatively, the mean astigmatism and surgically induced astigmatism(SIA) in group A was (0.74D±0.31)D and (0.69± 0.51)D,(0.69±0.29)D and (0.64± 0.40)D, (0.61 ± 0.27)D and (0.65±0.38)D, (0.54 ± 0.26)D and (0.59±0.33)D, respectively, and in group B was (1.11 ± 0.33)D and (1.19±0.74)D, (1.02 ±0.30)0 and (1.08±0.60)D, (0.89±0.31)D and (0.87±0.49)D, (0.78 ± 0.28)D and (0.77±0.40)D, respectively, and in group C was (1.09±0.27)Dand (1.15±0.70)D, (1.01±0.27)D and (1.03±0.54)D, (0.86±0.29)D and (0.84± 0.51)D, (0.79 ± 0.25)D and (0.79±0.37)D, respectively. The mean astigmatism and SIA in group A were lower than in group B and group C, and the difference was statistically significant(P<0.05). The difference between group B and group C was not statistically significant(P>0.05). The superior incision group showed against-the-rule astigmatic changes, whereas with-the-rule astigmatism was seen in the temporal incision group.Conclusions: There was a highly statistically significant difference in astigmatic and surgically induced astigmatism after temporal and superior unsutured clear corneal oblique incisions. The degree of astigmatic and SIA and the difference between the temporal and the superior incisions decreased over time. There was not statistically significant difference in astigmatic and SIA after oblique and tunnel unsutured clear corneal incisions.