It is needed because it is very one-sided for patients to judge whether there is a problem with their eyes just based on their vision. We divide the fundus into central and peripheral areas, and the central area refers to the macula. If there is no bleeding or exudation in the macula, the patient may not easily notice it, but the peripheral retina may have developed damage and treatment should be started. Therefore, it is best to check the eyes after the discovery of diabetes and then decide when to review it based on the situation. A fundus image can also be taken for later review.