Ocular fatigue is the major symptom of dry eye.

A total of 524 consecutive new patients (195 male, 329 female, 43.4 +/- 20.8 y.o.) were evaluated for the presence of ocular fatigue and/or dry eye. Dry eye was diagnosed based on our criteria, which included symptoms, vital staining, break-up time (BUT) measurement, and the Schirmer test. Among all the patients, 21.2% (111/524) reported symptoms of ocular fatigue and 15.3% (80/524) were diagnosed as having dry eye with symptoms. Of the 111 patients who complained of ocular fatigue, 51.4% (57/111) had dry eye, which was significantly higher than the 15.3% for the entire group (p < 0.001). Additionally, 71.3% (57/80) of dry eye patients with symptoms complained of ocular fatigue, which was also significantly higher than the 21.2% among all patients (p < 0.001). Dry eye patients had a greater number of complaints (4.3 +/- 2.1 per patient) compared to controls (1.9 +/- 1.3 per patient) (p < 0.001). These findings suggest that there is a strong relation between ocular fatigue and dry eye.