 This is a research study designed to test the utility of D-shaped bifocal lenses and PRIO Computer Lenses for persons using a computer. These are different types of eyeglass lenses and are commonly used when performing computer work. D-shaped bifocal lenses are designed for general purpose use and PRIO Computer Lenses are progressive addition lenses designed for using a computer and are not useful for driving or other tasks requiring clear distance vision. The study will examine how much work a subject completes during a 2-hr visit to the laboratory productivity and how a subject feels when working symptoms. The UAB Department of Optometry sponsors this research study. Interested individuals must be at least 40 years of age and have relatively good vision in each eye when wearing glasses and to do at least 4-hrs of computer work per workday. There are no other restrictions to enter the study. 