Contact lenses are considered medical devices and can be worn to correct vision, or for cosmetic or therapeutic reasons. People choose to wear contact lenses for many reasons. Aesthetics and cosmetics are often motivating factors for people who would like to avoid wearing glasses or would like to change the appearance of their eyes. Other people wear contacts for functional or optical reasons. When compared with spectacles, contact lenses typically provide better peripheral vision, and do not collect moisture such as rain, snow, condensation, or sweat. This makes them ideal for sports and other outdoor activities. Contact lens wearers can also wear sunglasses, goggles, or other eyewear of their choice without having to fit them with prescription lenses or worry about compatibility with glasses. Additionally, there are conditions such as keratoconus and aniseikonia that are typically corrected better by contacts than by glasses.