A multicenter study on definite and probably dry eyes

We compared the clinical features in 359 definite and 394 probable dry eye patients in 9 institutions. Probable dry eye was defined as those with either dysfunction of tear film or disorders of ocular surface. Definite dry eye was defined as those with both. The incidence of complaint of dry eye sensation was 15% in probable cases and 27% in definite cases. The difference was significant (p < 0.01). There were monthly fluctuations in incidence of subjective symptoms in definite cases and none in probable cases. The findings suggest that probable dry eye patients may consist of those with decreased tear secretion and those with some other types of dry eye.