Just a followup note to Mark's excellent advice. Those who are very nearsighted should get a periodic retinal exam by an optometrist or ophthalmologist. These days, most optometrists and ophthalmologists in the U.S. are proficient at dilated retinal exams using a technique called scleral depression, necessary to see the outermost parts of the retina where tears tend to occur. In any event, if a retinal tear or detachment is found, you will be sent promptly to a retinal specialist, who does nothing but repair retinas for a living. Regular optometrists and ophthalmologists don't do that type of procedure. Al