The results of nasal endoscopy depend on the degree of cooperation of the subject, the proficiency of the examiner, and the degree of narrowing of the nasal cavity itself; therefore, nasal endoscopy for nasal cavity disease can produce misdiagnosis. Therefore, it is usually necessary to use 2% dicaine with an appropriate amount of epinephrine before the examination to provide sufficient surface anesthesia and adequate contraction of the nasal mucosa, so that the nasal cavity is more relaxed during the nasal examination, so that areas that are not easily observed are not missed. It also facilitates careful observation of the nasal cavity, thus reducing the number of missed diagnoses.