Evaluation of the Functional Visual Range of a Catenary Curve-Based, Extended Depth-of-Focus Contact Lens for Presbyopia

Purpose: Employing "relative plus" (Add) power to extend the functional vision range is a primary method to correct presbyopia with contact lenses. Simultaneous vision contact lenses are typically associated with visual disturbances at higher Add powers, often resulting in compromised vision and necessitating specialized fitting methods. Among mature individuals suffering from presbyopia, we evaluated the visual performance of a catenary curve-based extended depth of focus (EDOF) optical profile contact lens with a simplified fitting process. Methods: Mature individuals suffering from presbyopia with Add requirements of +2.00 D or more were recruited. Monocular and binocular visual acuities were obtained across optical vergences ranging from -4.00 D to +2.00 D to generate defocus curves for best spectacle-corrected distance vision (baseline) and center-distance, catenary curve-based contact lenses (catenary). A subjective questionnaire evaluating the lenses was employed. Results: Twenty-four mature individuals suffering from presbyopia, average age 59.2 (range: 51-68 years) and average Add requirement of +2.24 D (range +2.00 D to +2.50 D) were enrolled. Under high-contrast conditions, the catenary lens provided functional binocular vision (0.30 logMAR or better) at all optical vergences from distance to -3.50 D (equivalent to 28 cm). Participants demonstrated a significant improvement (p < 0.05) in binocular visual acuity while wearing the catenary lens with an imposed defocus of -1.50 D to -4.00 D (equivalent to object distances from 66 cm to 25 cm). Subjective ratings with the catenary lens were equivalent to those documented at baseline. Conclusion: The catenary curve-based lenses provided a full range of functional vision while maintaining clear distance vision for individuals suffering from advanced presbyopia. Comparison with previous results involving this lens indicates that these findings are also generalizable to wearers with lower Add requirements. This EDOF design provides a universal Add which is sufficient for advanced presbyopia.