The normal range of vision for three-year-old babies is 0.5-0.6. This age is a critical period for the development of visual function. If you find that your baby’s vision is abnormal, you should go to the hospital for a review in time, and if it is still abnormal after the review, you need to have a dilated eye exam and wear glasses if necessary. You should pay attention to eye hygiene, develop good reading and writing posture, and should not read or write for more than 20 minutes in a row. Avoid close eye use, do not read in a jarring or shaking state, and electronic products, including television, should not exceed 15-20 minutes. Also avoid eye trauma, as this age group is less aware of protection and prone to accidents.