The sun produces many types of radiation. Some is the light we need for seeing. There is also infrared radiation that is invisible but felt as heat.
Ultraviolet radiation is also invisible.
More and more scientific evidence shows that long-term exposure to ultraviolet radiation can damage our eyes. With the thinning of the earth's ozone layer and the growing popularity of outdoor activities, there is a strong possibility that UV-related eye disorders will increase within the next decade. Ultraviolet radiation may contribute to the development of various eye disorders, such as macular degeneration , the leading cause of vision loss among older Americans, and cataracts , a major cause of visual impairment and blindness around the world. Everyone including children is at risk for eye damage that can lead to vision loss from exposure to UV radiation. Any factor that increases your exposure to sunlight will increase your risk.