What are the optical aids for visually challenged persons?

There are many additional resources which enable the visually handicapped person to develop their capabilities. These resources can be of two types: non-optical aids and optical aids. Optical aids include bifocal lenses, contact lenses, tinted lenses, other lens combinations, magnifiers and telescopic aids. While the lenses and their combinations are used to rectify visual limitations, telescopic aids are available to view chalkboard and class demonstrations.