Overview
Soft multifocal contact lenses are used for a variety of reasons in patient care. Multifocal contact lenses are most often used to correct presbyopic vision by providing a range of clear vision at both distance and near. Multifocal contact lenses correct vision at different distances by introducing a power gradient over the eye. They are designed using center near or center distance designs. For center near designs, the near addition is place in the center of the lens, and the power becomes more negative in the periphery. 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 in order to provide the near addition. Center near and distance designs have varying advantages and disadvantages for presbyopic vision correction, so a fitter may choose a specific design based on a patient's individual visual needs. 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 and able to allow maximum near correction, even with miotic pupil size changes associated with accommodation.
Plus lenses, or add powers, in spectacles are often used in the management of accommodative and binocular vision disorders. An add power, or plus lens, relieves accommodative demand. There is conflicting evidence on whether the add power in soft multifocal contact lenses can be used to manage accommodative and binocular vision disorders. Some case reports demonstrate benefits of multifocal contact lenses in accommodative insufficiency and convergence excess but the evidence is not clear and many previous studies utilize lenses that are not readily used anymore. Studies show that soft multifocal contact lenses alter accommodation in participants who wear lenses, but most studies use enter-distance lens designs, which is the most commonly used lens for myopia management.
Most studies that have evaluated accommodative ability and function while wearing soft multifocal contact lenses have examined center distance lenses. Because center distance lenses are used for myopia management, the interest has been to determine if children maintain normal accommodative function while wearing the lenses. Accommodative function while wearing center near lenses has likely not been studied often because these lens designs are used most in presbyopic populations who have no or waning accommodative ability and are using the lenses, specifically, to account for that accommodative inability.-Knowing how spectacle lenses with add powers effectively treat some binocular vision and accommodative disorders and understanding how center near multifocal contact lenses correct presbyopic vision, it is reasonable to hypothesize that center near multifocal contact lenses may provide a greater therapeutic effect for accommodative and binocular vision disorders than center near designs because the central portion of the lens is the addition power, unlike the center-distance lens designs. This study will aim to determine how accommodative function varies with center distance and center near multifocal contact lenses.
Eligibility
Inclusion Criteria:
- Ages 18 to ≤ 30 years old
- Acuity of 20/25 or better in both eyes with habitual contact lens prescription
- No history of ocular disease or active ocular inflammation
- No history of ocular or refractive surgery
- No current history of rigid contact lens wear
- Astigmatism ≤1.00 D
- Free of binocular vision disorder (strabismus, amblyopia, vergence dysfunction, accommodative dysfunction)
Exclusion Criteria:
- No prior or concurrent participation in myopia control or use of low dose atropine, multifocal contact lenses
- No use of any medications suspected to affect accommodation