This is a refractive error where the eyes see well at near distance, but have a hard time seeing far away. Normally, the eye works like a camera with light entering the eye being focused perfectly on the retina. The retina is analogous to the film in a camera and located at the back of the eye.  When a person is nearsighted, however, light wants to focus in front of the retina and visual images look blurry. By weakening the eye’s overall focusing power with glasses (using negative diopter power lenses) light can focus properly on the retina. Extremely nearsighted eyes tend to be longer or larger than average, which puts them at slightly increased risk for retinal detachment. The prevalence of nearsightedness seems to be increasing in our society … the reason for this is not entirely clear, but it may have something to do with the increase in near activities (i.e., iPads and Game Boys).

Dr. Timothy Root is a practicing ophthalmologist and cataract surgeon in Daytona Beach, Florida. His books, video lectures, and training resources can be found at:


  1. Like the online dictionary, it’s very useful for patient education, & useful as a training resource and for staff who are new the the eye service.


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