The prototypical patient, based on the total subject population, is a 38-year old, mildly myopic female who uses the computer screen about 5 hours per day. Average total VDT work experience is about 5 years. Most of the patients use full-color screens and sit between 21 and 22 inches away from the screen. A variety of visual symptoms is reported, with eyestrain (65 percent) and headaches (42 percent) being the most common complaints.