Changes in Visual Function According to the Addition of Center-near Designed Multifocals and Utilization as Contact Lenses for Fatigue

Abstract

Purpose: To compare changes in visual function according to single vision and additions of center-near simultaneous vision multifocal contact lenses and investigate the use as a functional contact lens for fatigue. Methods: Twenty young adult subjects(40 eyes, 26.63±4.36 years) participated in this study. Mean spherical refractive errors were–3.38±2.57 D, mean cylinderical errors were–0.46±0.31 D and mean spherical equivalent errors were -3.61±2.64 D. Subjects visited four times and wore single vision, multifocal LOW, MID, and HIGH addition lenses for each visit. They were asked to watch a video with subtitles on a cell phone (4.7 inches) at 40 cm for 60 minutes in order to induce accommodation. After that, MEM, distance and near contrast visual acuity (100% and 10%), near range of clear vision, near point of accommodation, near point of convergence, accommodative facility and stereoacuity were measured and subjective satisfaction was evaluated. Results: As the addition increased, MEM tended to increase and near point of accommodation decreased(p 0.05). Satisfaction with distance vision showed the highest score in single vision contact lenses. Conclusion: As the addition increases, an increase in MEM and a decrease in near point of accommodation are verified. However, differences in the other tests were mostly not significant. Therefore, in order to use the multifocal contact lenses as functional contact lenses, it may be necessary to trance changes in visual function after wearing for a longer period of time.