Sleep enough, but the eyes are still easy to fatigue, it may be caused by the following reasons: 1, refractive error: one of the most likely causes of eye fatigue, although sufficient sleep, but after excessive eye use because of the presence of refractive error, it is easy to eye fatigue. It is recommended to go to the hospital in time to wear suitable glasses for correction through optometry, which can alleviate this symptom. 2, dry eye: eyes will have dryness, soreness and other symptoms, dry eye patients should go to the ophthalmology department for tear secretion test, tear film rupture time measurement, etc. There are some patients who have dry eye syndrome and although they get enough sleep, the effect of dry eye syndrome will make their eyes very easily fatigued. For dry eye, it is usually treated with eye drops using artificial tear drops. After the treatment of dry eye, the symptoms of fatigue will be relieved. 3, glaucoma: It is recommended to go to the hospital ophthalmology to measure the intraocular pressure, there are some patients with glaucoma can also cause eye fatigue, especially chronic glaucoma is not easy to be detected. Despite sufficient sleep, the eyes are still easily fatigued. If the intraocular pressure exceeds the normal value and the eyes are often sore, swollen and fatigued, it is recommended to seek prompt and directed treatment or medication from an ophthalmologist.