Accommodative Behaviors in Multifocal Contact Lenses

Soft multifocal contact lenses are used for a variety of reasons in patient care. In fact, studies have shown that soft multifocal contact lenses alter accommodation. While most often used to correct presbyopic vision, these lenses are also used in the management of accommodative and binocular vision disorders along with myopia management. Multifocal contact lenses correct vision at different distances by introducing a power gradient over the eye thus providing a range of clear vision at both distance and near.

For center near designs, the near addition is placed in the center of the lens, and the power becomes more negative in the periphery. Generally, it is thought that center near designs provide the most accommodative relief and superior near vision because the near addition is centered in the pupil. These lenses allow maximum near correction, even with miotic pupil size changes associated with accommodation. Conversely, for center distance designs, the distance prescription is placed in the center, and the power of the lens becomes more positive in the periphery to provide the near addition. To date, most studies have used center-distance lens designs to evaluate accommodative ability and function. Accommodative function while wearing center near lenses has likely not been studied often because these lens designs are used most in populations with no or waning accommodative ability (i.e. presbyopic patients). In this population lenses are used, specifically, to account for that accommodative inability.

Center near and distance designs have varying advantages and disadvantages for presbyopic vision correction. Selection of lens design can be based on a patient's individual visual needs. There is conflicting evidence on whether the add power in soft multifocal contact lenses can be used to manage accommodative and binocular vision disorders. These lenses do offer relief of accommodative demand associated with both accommodative and binocular vision disorders. It has been hypothesized that center near multifocal contact lenses provide a greater therapeutic effect as the central portion of the lens is the addition power. There have been case reports demonstrating benefits of multifocal contact lenses in accommodative insufficiency and convergence excess. Center distance lenses are used most often for myopia management. In these situations, the interest has been to determine if the child can maintain normal accommodative function while wearing the lenses. This study will aim to determine how accommodative function varies with center distance and center near multifocal contact lenses.