中国眼耳鼻喉科杂志2022年1月第22卷第1期 . 63 . re the effect of intermittent positive pressure irrigation of endoscopic lens on the efficiency of functional endoscopic sinus surgery (FESS). Methods A total of 50 patients with chronic rhinosinusitis with nasal polyps (CRSwNP) who had undergone FESS in Eye & ENT Hospital of Fudan University from October 2019 to May 2020 were enrolled in this study. A prospective randomized controlled study was conducted. All patients were randomly divided into observation group (n=20) and control group (n=30). Intermittent positive pressure irrigation of nasal endoscopic lens was performed to keep the endoscope lens clear during operation in observation group. In the control group, when the operation of vision was not clear during the operation, the operation was suspended and the lens was moved to scrub. Finally, the operation duration of the two groups was compared. Results The average operation time in the observation group and the control group was (80±4) mins and (101±6) mins, respectively. The difference was statistically significant (P<). Conclusions In the course of FESS, intermittent positive pressure irrigation of nasal endoscopic lens could keep the vision clear and save the operation time. 【Key words】 Chronic rhinosinusitis wi