There are a variety of ocular diseases that affect the eye in such a way that functional vision cannot be achieved with regular glasses. For most healthy eyes, 20/20 vision is attainable with spectacle correction. Low vision patients often see 20/70 or worse, even after being best corrected with glasses. When vision is degraded to this extent, everyday activities such as reading the mail, navigating a room, cooking, etc. can become very difficult. Disease-specific visual aids (i.e. customized magnifying glasses, etc.) can be used to help patients achieve functional vision and maintain independence.