Research Of The Different Incision To Correct The Pre-existing Cornea Astigmatism And The Change Of Cornea During Small Incision Non-phacoemulsification Surgery

Objective:To study the effect of straight scleral tunnel incision with different distance from limbus at the maximum curvature meridian on preoperative corneal astigmatic, and study t variations in the number of corneal endothelial cells during small incision non-phacoemulsification surgery.Methods:72 eyes of 72 patients with preexisting cornea astigmatism between 1.0 D～2.0 D will be divided into three groups according to the distance from limbus at random and 24 eyes in every group. Group A had incision 1.5mm away from limbus, Group B had incision 2.0mm away from limbus and Group C had incision 2.5mm away from limbus. All patients were treated with small incision non-phacoemulsification surgery and posterior chamber intraocular lens implantation through a 6mm straight scleral tunnel incision at the maximum curvature meridian. Each group respectively preoperatively, one week,one month and three months postoperatively was measured average corneal astigmatism, visual acuity and the quantity of corneal endothelial cell. observation of postoperative corneal astigmatism, study of three kinds of incisions on preoperative corneal astigmatic correction function and observe the variations in the number of corneal endothelial cells.Results:Postoperatively each group at each time point average corneal astigmatism were compared with preoperative decreased significantly. Respectively difference was are significant. And, on the 1 postoperative week average corneal astigmatism between the 3 groups of corneal astigmatism comparison, there were significant differences (P< 0.05), the mean postoperative corneal astigmatism:C> B> A group. After 1,3 months between the 3 groups in the mean corneal astigmatism also showed significant difference (P< 0.05), the mean postoperative corneal astigmatism:C> B > A group. Patients with uncorrected visual acuity between the 3 groups had significant difference at 1 week poatoporaively. And after 3 months,3 groups of patients with uncorrected visual acuity without significant difference. Postoperative corneal endothelial cells quantity change showed no significant difference between the three groups (P> 0.05)Conclusions:The straight scleral tunnel incision at the maximum curvature meridian can correct preoperative astigmatism in a certain extent during small incision non-phacoemulsification surgery. Also, the incision location from the corneal center close, early correction of preoperative corneal astigmatic effect is better. Corneal endothelial cells lost has no related with the incision location from the corneal during small incision non-phacoemulsification surgery.