AIM:To research into the etiology of dry eye to supply evidence,which the diagnosis is based on,to decrease the misdiagnosis.METHODS:The causes of 83 patients with dry eye were reviewed,of which 16 patients were misdiagnosed.According to the symptoms,less stability of tear film,decreased secretion of tear and damage on the surface of eyeball,diagnosis was made systematically.RESULTS:The most common causes were video display terminal syndrome(29%),followed by chronic blepharitis(14%),Sjogren’s syndrome(14%).10 patients were misdiagnosed for chronic conjunctivitis,2 patients were misdiagnosed for viral keratitis,and other 4 patients were misdiagnosed for etiology of dry eye.CONCLUSION:Although these causes do not induce dry eye essentially,understanding and searching for them constructively supplies evidence to diagnosis and reduces misdiagnosis.