A double-blinded randomized clinical trial for pain perception: The efficacy and safety of topical cold saline solution anesthesia in phacoemulsification

PURPOSE: To compare the efficacy and safety of cold saline solution (0.9% NaCl) with topical ophthalmic proparacaine for maintaining topical anesthesia of patients undergoing phacoemulsification surgery. METHODS: The prospective, double-blinded, and randomized clinical study was randomly assigned to two groups that underwent phacoemulsification surgery due to cataracts. The cold saline group included 86 eyes of 86 patients with topical anesthesia of cold saline solution alone. The proparacaine group included 84 eyes of 84 patients with topical ophthalmic proparacaine (room temperature) anesthesia alone. The patients were scored according to a pain survey questionnaire of Visual Analog Scale (VAS) ranked between 0 and 10. The surgeon scored surgical experience by a Surgeon Questionnaire Scale (SQS) in three parameters, each of which was ranked from 1 to 3 based on questions regarding ease and comfort during the surgery. RESULTS: The mean VAS scores were 1.29 ± 0.65 and 1.22 ± 0.66 for the cold saline and proparacaine groups, respectively (P = 0.182). The mean scores of SQS (lower values represented favorable results) were 4.11 ± 0.76 and 3.97 ± 0.74 in the cold saline and proparacaine groups, respectively (P = 0.163). Ten patients in the proparacaine group experienced corneal epitheliopathy in the postoperative period. CONCLUSION: As an easily accessible and cost-effective method, cold saline solution alone might be an alternative to topical ophthalmic proparacaine alone with comparable safe and effective results. The absence of allergic or toxic effects also provided a significant advantage in the cold saline application.