Effect of Defocus Incorporated Multiple Segments (DIMS) spectacle lens wear on visual functions in myopic children

The Defocus Incorporated Multiple Segments (DIMS) spectacle lens slows myopia progression and axial elongation in myopic children in average by 60% over 2 years. This study evaluates and compares visual functions in myopic children after 2-year of wearing DIMS lenses. Seventy-nine Chinese myopic (mean spherical equivalent refraction =-2.97± 0.97D) children (age 8 to 13 years) who participated in and completed a double-blinded randomized clinical trial of DIMS lenses were included. The children wore the DIMS lenses full-time (more than 10 hours per day) over 2 years. Their best corrected visual acuity, binocular visual functions and accommodation with full correction for distance were measured at baseline before lens wear and then repeated every 6 months over 2 years. Distance and near horizontal phoria were measured using Howell distance and near phoria cards. Amplitude of accommodation was measured by push-up method using the RAF rule. Lag of accommodation was evaluated using an open-field autorefractor. Visual functions at baseline and at 2-year were compared using paired t-tests. Improvement in best corrected distance visual acuity (mean difference = 0.09 ±0.06, p=0.00) and stereoacuity score (mean difference=5.72 ±14.34, p=0.02) were found after DIMS spectacle lens wear, but were clinically insignificant. There were no significant changes in mean near visual acuity, distance and near phoria, amplitude of accommodation and lag of accommodation (p>0.05) after two years of DIMS lens wear when compared to baseline. The findings indicated that long-term wear of DIMS spectacle lens did not affect visual acuity, binocular function and accommodation while slowing myopia progression in myopic children. This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.