Visual Quality Assessment and Comparison of Monofocal and Multifocal Scleral Lens Designs: A Pilot Study

Abstract

Purpose: To compare visual quality, contrast sensitivity, stereopsis, subjective vision, and comfort between monofocal and multifocal scleral lens (SL) designs. Methods: An experimental, cross over and short-term pilot study has been performed. Nineteen presbyopic patients (51.9±3.8 years) with regular corneas participated voluntarily in the study and Onefit MED monofocal and multifocal SL designs were fitted bilaterally. Subjective vision and comfort, contrast sensitivity function, stereopsis, high- and low-contrast visual acuity (VA) at 4 m and 40 cm under photopic and mesopic conditions, and defocus curves were measured. Data analysis was performed with nonparametric tests. P<0.05 was considered as statistically significant. Results: Mean addition power of the prescribed lenses was 1.72±0.38 diopters. Multifocal design showed a statistically significant improvement for intermediate and near vision in the defocus curve under photopic and mesopic conditions (P<0.05), however, worsening in stereopsis (P<0.05) and contrast sensitivity for high spatial frequencies (P<0.05). Distance visual acuity (VA) showed significantly lower values under mesopic conditions for high- and low-contrast tests (P<0.05), and on low-contrast test under photopic conditions (P<0.001) with the multifocal design. Conclusion: Multifocal SLs showed better visual performance at intermediate and near distances without compromising distance vision under photopic conditions for a high-contrast test when compared with monofocal design.