ABSTRACT
Background Cataract surgery can induce the occurrence of dry eye because of the influence of incision on corneal nerve fibers and the change of corneal regularity derived by surgery.Objective This study was to investigate the change of regularity of anterior corneal surface,tear film and astigmatism caused by the process of manual small-incision cataract surgery (manual SICS) and phacoemulsification (Phaco).Methods A prospective non-randomized controlled study was designed.Fifty eyes of 46 age-related cataract patients were included in this clinical study.Thirty eyes of 30 patients received the manual SICS,and other 20 eyes of 16 patients underwent Phaco.Corneal irregularity measurement (CIM),shape factor (SF) and corneal astigmatism were assessed by the corneal tomography examination,the subjective symptoms were scored and tear film break up time (BUT),Schirmer Ⅰ test (S Ⅰ t) were examined before surgery and 1 day,1 week,1 month after surgery.The examined parameters were compared among different time points and two groups.This study was approved by Ethic Committee of Affiliated Eye Hospital of Wenzhou Medical College,and written informed consent was obtained prior to operation.Results The CIM values were gradually increased with the prolong of time after operation,showing a statistically significant difference dependent on time (Ftime =22.864,P =0.000),and CIM value of 1 day,1 week and 1 month after operation was higher than that of before operation (P＜0.01).However,no significant difference was found in CIM value between two groups in different time points (Fgroup =0.062,P =0.804).There was no significant difference in SF values with time prolong (Ftime =4.600,P =0.428) and different groups (Fgroup =0.009,P =0.925).The BUT was gradually reduced with the time prolongs with the considerably difference (Ftime =39.384,P=0.000).Obviously decreases of BUT values were seen in 1 week and 1 month in comparison with 1 day after operation (both P=0.000).But no significant change was found in BUT between two groups in various time points (Fgroup =0.000,P=0.983).In the manual SICS group,the difference was found in S Ⅰ t values between before operation and 1 week or 1 month after surgery(P＜0.01).Surgery associated astigmatism (SIA) was existed in the operative eyes in various time points after operation.With time lapse,SIA value was declined with a significant difference (Ftime =21.479,P =0.000),the difference also was found in different groups (Fgroup =8.709,P =0.005),and SIA value in the Phaco was significantly lower than that in the manual SICS group (P＜0.01).Conclusions In the present study,in the early stage after manual SICS and Phaco,SIA appears due to the irregular change of the anterior corneal surface increases and stability of tear film worsens.