Purpose: The purpose of this study was to determine the limitations of increasing add powers to objective and subjective visual function by evaluating three multifocal soft contact lens (SCL) designs in five add powers.
Methods: Ten adults with normal eyes and no refractive astigmatism participated in this study. Visual assessment was evaluated with a single vision control SCL and 3 different center distant power multifocal SCL designs with add powers of +1.00, +2.00, +3.00, +4.00 and +5.00. The multifocal lens designs were categorized as Concentric Aspheric Addition Design (AA), Concentric Linear Addition Design (LA), and Concentric Constant Addition Design (CA). Subjects wore their spectacle correction over the experimental lenses during testing to correct their foveal refractive error. Binocular distant (6m) and near acuities (40cm) were measured in logMAR units at 100% and 10% contrast. Global stereopsis was measured with random dot targets at 40 cm. Participants filled out questionnaires to rate the visual quality and perceived potential success for each of the lens sets.
Results: With one exception (CA-2), the majority (>50%) of subjects believed they could be academically successful with any lens design with an add power of +3.00 D or less. All lens designs with either +4.00 or +5.00 D add powers were rated significantly (p
Conclusions: Future lens designs will likely be limited to +3.00 D. powers, unless the design is similar to that of Aspheric Add Design. A patient’s visual quality ratings and visual acuity performance in these multifocal soft lenses are expected to be comparable to a single vision soft lens.
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