Abstract: Objective The objective of this study was to compare the degree of tension, pain, and cooperation between patients who underwent two implantable collamer lens(ICL)implantation surgeries under surface anesthesia, and to analyze whether there was a difference in pain between the two eyes and explore the possible causes of the pain in order to examine the ideal interval between two ICL operations. Methods A total of 120 patients who underwent binocular ICL surgery were enrolled. Among them, 18 were men and 102 were women. Patients were randomly divided into 1-day and 1-week interval groups. ICL implantation surgeries were performed in both eyes according to the research plan. All operations were performed under surface anesthesia, and ICL implantation was performed using a transparent corneal incision. The degree of tension of patients was evaluated by a visual analog scale(VAS)before the operation. The degree of cooperation of patients and the operation duration were evaluated and recorded during the operation, and the degrees of pain and overall satisfaction were evaluated by a VAS scale after the operation. Additionally, patients were asked to estimate the operation duration. The difference between binocular score in the two groups was statistically analyzed and compared, as well as the relationship between the degree of pain and the general information of patients such as gender, age and so on. Results In both the 1-day and 1-week interval groups, the tension of the patients during the second eye surgery was reduced(1-day interval group: P<0.01; 1-week interval group: P=0.011), the degree of pain significantly increased(both groups: P<0.01), the degree of satisfaction decreased(both groups: P=0.001), and the estimated operation duration was longer(both groups: P<0.01). In the second eye surgery, the degree of cooperation of patients declined(both groups: P=0.002), but it did not lead to an increase in the estimation of operation duration(1-day interval group: P=0.481; 1-week interval group: P=0.499). Also during the second eye surgery, a significant number of patients underestimated the pain they had experienced during the first eye surgery. The bias of memory of the 1-week interval group was statistically significant(1-day interval group: P=0.082; 1-week interval group: P=0.011. The changes in all indexes between the first and second eyes in the 1-week interval group were greater than those in the 1-day interval group, but there were no significant differences between groups(P>0.05). Multivariate regression analysis and nonparametric tests with multiple independent samples showed that young people without childbirth history tended to experience higher levels of pain during surgery. Conclusion Compared with the first eye surgery, the degree of tension decreased, the amount of pain increased, and the degree of cooperation decreased in the second eye surgery. This result may be mainly related to psychological factors; therefore, psychological intervention is warranted before the second eye surgery. No significant difference in pain existed between the 1-day and 1-week interval groups. Our results indicate that the time interval between two eye surgeries can be determined according to the patient's request.

Key words: Implatable collamer lens implantation, Psychological intervention, Interval of binocular surgery, Visual analog scale, Posterior chamber lens