Eyestrain and blurred vision can be caused by overuse of eyes, presbyopia, cataracts and so on. 1. Excessive use of eyes: prolonged use of eyes, improper use of eyes, lack of sleep and other reasons can lead to excessive use of eyes, eyestrain, blurred vision, eye soreness and so on. 2. Presbyopia: due to ageing, the crystal hardens, the elasticity decreases, the eye’s adjustment ability decreases and a series of symptoms appear, such as blurred vision, visual fatigue, etc., especially after a long time of eye use. 3. Cataract: Cataract occurs mostly in middle-aged and old people, which is the result of the long-term effect of internal and external factors, mainly manifested as vision loss, blurred vision, etc., but also eye swelling and pain, photophobia and other symptoms of eyestrain. Eyestrain blurred vision, there may also be other reasons, it is recommended to go to the hospital in a timely manner, clear causes for standardized treatment.