The possible causes of watery eyes and blurred vision are: 1. Refractive error causing visual fatigue. Refractive error, which is the inability of external objects to focus in the macular central sulcus of the retina, prevents the formation of clear objects. Patients with nearsightedness, farsightedness or astigmatism without proper glasses may not affect their vision if they are young and have good regulation. If the adjustment power decreases, there will be eye swelling, tearing and blurred vision. 2. Dry eye disease. The most common symptoms of dry eye disease include eye fatigue, dryness, eye swelling, photophobia, tearing, and blurred vision if corneal clouding occurs. 3, presbyopia. Presbyopia is a decline in eye regulation caused by hardening of the lens. If you do not wear presbyopic glasses, you will experience eye swelling, tearing and blurred vision when you look close, and you need to wear appropriate presbyopic glasses.