Performance lenses are often prescribed to allow for focusing and eye teaming being more efficient. They can be very important and should be used during all near-point work (homework, computer, reading etc.). Note that these glasses are not prescribed to provide increased clarity; clarity is already available without glasses. These lenses are designed to enable your eyes to process information, such as from a book or computer, with greater balance, ease and efficiency.
Sometimes these lenses have a special tint, and they may also employ a variety of prism powers to maximize performance, reduce physical symptoms due to extended close visual work, and protect the eyes from the negative effects of screen-time from electronic sources.