Eyesight/ˈaɪsaɪt/ Definition 1 of 3Pro Tip 1/3Visual Quality Eyesight refers to how clear or sharp one's seeing ability is. Even at night, her eyesight is sharp enough to spot small details. Pro Tip 2/3Aging Effects Age can affect eyesight, implying a decline or need for glasses. Grandpa's eyesight isn't what it used to be; he needs his reading glasses. Pro Tip 3/3Health Link Eyesight can indicate overall health, with conditions like diabetes affecting it. The doctor checked his eyesight to monitor his diabetes.