Fig. 11. Annular bifocal lens. In some annular designs, the near vision correction is in the center of the lens; in other designs, distance correction is in the center. (Stein HA, Freeman MI, Stein RM, Maund LD (eds): Basics of Soft Contact Lenses. In: Contact lenses: Fundamentals and Clinical Use, p 85. Thorofare, NJ, Slack Inc, 1996)