A vision test is one of the most routine eye examinations, and many diseases require a preliminary determination through a vision test, which generally costs$1. If, after the vision examination, there is a significant loss of vision, then a routine eye examination is performed to understand the specific cause of the loss of vision. The treatment for vision loss caused by different diseases is different. For example, vision loss caused by the presence of refractive error in the eye can be improved by wearing frame glasses or corneal contact lenses. In case of cataract or fundus disease, it may be necessary to improve vision through surgery. Moreover, the effect of fundus disease on vision is usually irreversible, so only early detection and early treatment can prevent serious vision damage.