Effect of Diabetes on Surgically Induced Astigmatism in 4 mm Corneal Tunnel Phacoemulsification Surgery

Purpose: To analyse the effect of diabetes on surgically induced astigmatism in 4 mm corneal tunnel phacoemulsification surgery. Patients and Method: The records of patients who had cataract surgery in 2002 at Ophthalmology Clinics were retrospectively reviewed. 28. eyes of 22 diabetic patients and 36 eyes of 27 non-diabetic control patients which underwent 4 mm clear corneal tunnel incision phacoemulsification surgery were included in the study. The demographic information, preoperative fasting blood glucose levels, preoperative and postoperative keratometric readings were available in the records. The surgically induced astigmatism was analysed by vector analysis and vector decomposition. The difference between the diabetic group and the control group for the parameters such as surgically induced astigmatism; with the rule, against the rule, with the wound, against the wound components and spherical equivalent changes were statistically tested. Results: The amount of surgically induced astigmatism in diabetic patients (1.53+/-1.31 diopters (D)) was greater than the control patients (0.94+/-0.59 D) and the difference was statistically significant (p = 0.019<0.05). As for against rule components the difference between the diabetic (0.82+/-0.99 D) and the control groups (0.29+/-0.33 D) was statistically very significant (p=0.007<0.01). In the diabetic and control groups the means of the with the rule components were 0.70+/-0.76 D and 0.64+/-0.57 D; with the wound components were 0.48+/-0.65 D and 0.29+/-0.33 D; against the wound components were 1.05+/-1.28 D and 0.61+/-0.56 D and spherical equivalent changes were 0.31+/-1.17 D and 0.34+/-0.72 D respectively. For these parameters the difference between groups was not statistically significant (p>0.05). Conclusion: The surgically induced astigmatizm in 4 mm clear corneal tunnel phacoemulsification surgery in diabetic corneas was greater than in the control corneas. It was thought that this result may be related to the effect of diabetes on corneal function, structure and wound healing process.