The Effect of the Corneal Astigmatism in Changed Cataract Surgery Incision with the Corneal Topography

Abstract

Objective To observe the effect of the corneal astigmatism in cataract surgery incision which selected according to corneal topography to further reduce the preoperative corneal astigmatism. Meth-ods Computer-assisted corneal topography was used to examine the 126 eyes of 123 patients preoperatively.The cases were divided into 5 groups randomly. Group A: Manual small incision cataract surgery (MSICS) Group: Superior anti-bow sclera tunnel incision was made on 22 eyes of Group A. Group B: MSICS Group: The anti-bow sclera tunnel incision was made on the steepest meridian according to the corneal topography ex-amined preoperatively on 28 eyes. Group C: Phacoemulsification Group: Superior clear corneal incision was made on 24 eyes of group C. Group D: Phacoemulsification Group: The clear corneal incision was made on the steepest meridian according to the corneal topography examined preoperatively on 26 eyes. Group E: MSICS Group: incision was made on the steepest meridian according to the corneal topography The straight sclera tun-nel examined preoperatively on 26 eyes. The corneal topography at 1 day and 7 days after surgery was ob-served and recorded except for visual acuity and so on. Results ①Visual acuity: The differences were not sta-tistically significant among these groups which Visual acuity was above 0.5 after 1 day and 7 days except the one between Group B and Group E after 7 days. ②Astigmatism axis conversion: The conversions were not sig-nificant from Group A to Group D. There were 12 cases changed in Group E. ③Corneal astigmatism: In Group A, the differences were not statistically significant among pre-operation, 1 day and 7 days. In Group B, the val-ues of corneal astigmatism in 1 day after surgery were a little more decreased than pre-existing ones, but were statistically significant 7 days later. The values of Group C and D were a little greater in 1 day after surgery and reduced 7 days later, however the values of Group C were higher. In group E, the differences between pre-oper-ation and post-operation were not statistically significant until 7 days later. Comparison of the corneal astigma-tism in Group A and Group B, Group C and Group D, Group A and Group C was not statistically significant.Group B and Group D had statistically significant difference in postoperative corneal astigmatism after 1d but opposite after 7d. On the contrary, Group B and Group E had no statistically significant difference in postopera-tive corneal astigmatism after 1d but opposite after 7d. Conclusions According to the corneal topography, it can reduce the surgical induced astigmatism or the pre-existing astigmatism and improve the visual acuity in short-term. There is an important clinical value to further improve the vision quality in postoperative cataract patients. Key words: Corneal topography; Cataract surgery incision; Corneal astigmatism