Nearsightedness, also called myopia, causes good near vision but poor vision in the distance. This results from the eye not having a perfectly round shape, which changes the focus point of light entering the eye. Eye doctors detect nearsightedness during an eye examination. Though every nearsighted person requires a slightly different eye glass correction, most people can have good vision with the right prescription.
Single-Vision
Single-vision prescription eyeglasses sharpen images in the distance, says the American Optometric Association. A nearsighted person likely wears the glasses most of the time, because good distance vision is important for many daily activities--such as driving. Some people find that leaving the glasses on at all times works well; other people may find it necessary to take off the eyeglasses for reading or other close-up work.
Bifocal
Bifocals have a horizontal line in the lens. The top of the lens has the distance correction; the bottom has a prescription for reading. Many people around age 40 begin having difficulties with reading, says the American Optometric Association. This occurs when the natural lens of the eye loses its ability to focus, a condition referred to as presbyopia. When this occurs, nearsighted people who once had clear near vision find reading difficult. A bifocal lens helps with reading and distance, though some people have a hard time adjusting to the line in the lens.
Progressive Lenses
Similar to a bifocal, progressive lenses allow a person to see in the distance and near, but they also give good vision in the intermediate distance--such as the dashboard in the car or the computer screen. Progressive lenses don't have the line through the lens, but the different corrections in the lenses blend. Many people prefer progressives for cosmetic reasons, preferring not to have the line in the lens. Progressive lenses require time to adjust. For example, the wearer can't move her eyes to look at an object to the side but must turn her head. A good rule for the wearer is to point her nose wherever she wants to look. Though awkward at first, many people adjust nicely to progressive lenses and their multi-distance use.
Computer Glasses
Many people who use single-vision lenses and bifocal lenses prescribed for distance vision have a difficult time working on the computer. Nearsighted people who don't wear progressive lenses may find a pair of single-vision glasses set for computer use may help considerably. If a person has difficulty with the computer screen, she should inform the eye doctor, who can calculate a prescription. However, the doctor must know the exact distance between where the person sits and the screen. If the person shifts between the computer screen and reading, and both cause difficulty, a special set of bifocals designed for computer and reading may offer a solution, says Dr. Larry K. Wan and Dr. Gary Heiting with All About Vision.
