Comparison of phacoemulsification with 2.2mm and 1.8mm transparent corneal incisions on corneal astigmatism

Objective To investigate the effect of phacoemulsification with 2.2mm and 1.8mm transparent corneal incisions and foldable posterior chamber intraocular lens implantation on corneal astigmatism and visual function. Methods In a prospective study,all 60 eyes of 60 patients with cataract were divided into two groups randomly.Group A and B received superior clear comeal incisions at 11 o' clock and had phacoemulsification (Group A with Intrepid Infmiti System,implanted SN60WF IOLs; Group B with Stellaris System,implanted MI60 IOLs).The changes of visual acuity,corneal astigmatism and corneal thickness were determined pre-operation and 1 day,1 week,4weeks,and 6 weeks post-operation with Standard logarithmic visual acuity charts and Pentacam distinguishly.Using Vector Analysis to calculate Surgery induced astigmatism at 4 weeks and 6 weeks post-operation. Results The corneal astigmatism on the first day after operation was significant in both groups,later decreased gradually and stabilized at 4 weeks post-operation,there was no significant difference,statistically (All P ＞0.05).The surgery induced astigmatism of Group A and B at 4weeks and 6 weeks post-operation was (0.28±0.09)D,(0.27±0.09)D; (0.27±0.10)D,(0.25±0.10)D separately,there was no statistically significant (All P ＞0.05).In visual acuity,corneal thickness in two groups pre-operation and 1 day,1 week,4 weeks,6 weeks post-operation there was no statistically significant (All P ＞0.05). Conclusions The surgery induced astigmatism after phacoemulsification with 2.2mm and 1.8mm transparent comeal incisions is very small.Both groups refractive status become stable quickly,both surgical systems are safe and effective in microcoaxial phacoemulsification.In all the early postoperative can obtain satisfactory uncorrected visual acuity. Key words: Surgery induced astigmatism;  Corneal astigmatism;  Phacoemulsification