PURPOSE: Defocus Incorporated Soft Contact (DISC) lenses with +2.50 D myopic defocus reduced myopia progression by 25% in a previous randomised clinical trial (RCT). The current study aimed to evaluate if a stronger myopic defocus, +3.50 D with variable myopic defocus (DISC3.5plus), could slow myopia progression compared with single vision (SV) soft contact lenses in a 12-month RCT. METHODS: Conducted from December 2018 to January 2021, the current RCT randomly assigned myopic children to wear DISC3.5plus (n = 87) or SV (n = 80) lenses. Myopia progression and axial elongation were compared between the two groups. Analyses were performed for both enrolled and completed participants. RESULTS: For all enrolled participants, the DISC3.5plus group had significantly less myopia progression (mean difference: -0.15 ± 0.07 D, p = 0.02) and axial elongation (mean difference: 0.04 ± 0.02 D, p = 0.04) than the SV group at 6 months but not at 12 months (myopia progression: p = 0.11
axial elongation: p = 0.13). For completed participants, the DISC3.5plus group (n = 33) had reduced myopia progression at both 6 months (0.25 ± 0.07 D, p = 0.002) and 12 months (0.19 ± 0.09 D, p = 0.049) compared with the SV group (n = 40), but not in axial elongation (6 months: p = 0.16
12 months: p = 0.32). In January 2020, the coronavirus pandemic disturbed contact lens-wearing patterns. CONCLUSION: DISC3.5plus lenses significantly slowed myopia progression and axial elongation compared with SV lenses for all enrolled participants over 6 months. The pandemic hindered longer term efficacy follow-up and sample size
thus, further investigation with more participants is needed to confirm sustained treatment effects.