High-defocus DISC3.5plus contact lenses: one year results

Paper title: Myopia control using a modified optical defocus soft contact lens in schoolchildren – A 12-month randomised double-masked control trial

Authors: Zhang H (1,2), Leung KY (3), Leung M (4), Tang WC (3), Wong CK (3), Liu KK (3), Tse DYY (2,3), Lee PH (5), Lam CSY (2,3)

1. School of Medicine, Nankai University, Tianjin, China
2. Centre for Eye and Vision Research, Hong Kong, China
3. Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
4. Discipline of Optometry and Vision Science, Faculty of Health, University of Canberra, Canberra, Australia
5. Southampton Clinical Trials Unit, University of Southampton, Southampton, UK

Date: March 2025

Reference: Zhang H, Leung KY, Leung M, Tang WC, Wong CK, Liu KK, Tse DYY, Lee PH, Lam CSY. Myopia control using a modified optical defocus soft contact lens in schoolchildren-A 12-month randomised double masked control trial. Ophthalmic Physiol Opt. 2025 Jun;45(4):969-981.

[Link to open access paper]

Myopic eyes have been shown to be typically prolate in shape, which leads to increasing relative peripheral hyperopia away from the central retina, particularly nasally. Previous studies, including the DIMS study, have reported nasal peripheral hyperopia exceeding +2.50 D in myopic children. 1-5 The DISC3.5plus lens was developed as a modified version of the original DISC (Defocus Incorporated Soft Contact) lens design. The original DISC design was a custom-made concentric bifocal contact lens design, with alternating distance correction and +2.50D zones of myopic defocus.6  The myopic defocus was increased from +2.50 D to +3.50 D to offset approximately 0.80 D of accommodative lag observed in the original DISC study (unpublished data). Myopic defocus in the outer rings was also increased, reaching up to +6.00 D, to counteract the increasing peripheral hyperopic refraction. This study tested whether the updated design improved myopia control compared to single vision lenses over 12 months.

The study was a one-year, double-masked randomised trial conducted in Hong Kong between 2018 and 2021. Children aged 8–13 years with myopia between –1.00 and –5.00 D were randomly assigned to wear DISC3.5plus or single vision (SV) soft lenses for a year. All lenses were silicone hydrogel, with a monthly replacement schedule. Outcome measures included cycloplegic spherical equivalent refraction (SER) and axial length (AL) at baseline, 6, and 12 months. Analyses were performed for both intention-to-treat and a sub-group of children who completed with study with consistent lens wear. These adjustments were made for delays in follow-up due to COVID-19. 

Key findings were as follows.

• Over 6 months, mean myopia progression and axial elongation with DISC3.5plus were –0.25 D and 0.11 mm, compared to –0.40 D and 0.15 mm with single vision lenses, respectively - representing at 38% refractive and 27% axial length control effect.
• Among children who completed the study with consistent lens wear of 6+ hours per day, mean myopia progression over 12 months was 0.19 D less in the DISC3.5plus group.
• No significant difference in axial elongation was found at 12 months in the per-protocol group.
• Visual acuity was slightly reduced at near (high/low contrast) and distance (low contrast) with DISC3.5plus, but distance high-contrast acuity was similar between groups.

Although the DISC3.5plus lens is not yet commercially available, the study offers useful insights into how stronger myopic defocus profiles may influence early myopia control outcomes. The first 6 months showed promising reductions in refractive progression and axial elongation compared to single vision lenses. The authors suggest that increased myopic defocus may enhance treatment effect compared with the DISC lens, but also state that the DISC3.5 lens was “comparable with soft contact lenses having 2.00 or more dioptres of myopic defocus”.

Read more about how the peripheral retina responds to multifocal contact lens wear here.

The study also highlighted how stronger defocus profiles may affect visual performance. Distance acuity remained comparable to single vision lenses, while small reductions in near high contrast (a few letters) and larger reduction in low-contrast distance and near acuity (just over 1 line) were observed, which may be important when evaluating the feasibility of stronger-defocus technologies in everyday wear. No direct comparison between visual performance in different lens designs was made, however. Importantly, monocular accommodation and stereoacuity were unaffected compared to single vision.

While the longer-term efficacy of this design remains unclear due to pandemic-related limitations in participant wearing time and follow-up, these early findings suggest that using stronger defocus profiles could be incorporated into future lens designs. 

The most significant limitation to this study was disruption from the COVID-19 pandemic, which reduced contact lens wear, limited participant follow-up, and led to a high dropout rate. These factors reduced sample size and introduced variability into the results, meaning the findings cannot confirm sustained efficacy beyond the short term. The authors noted that using daily disposable lenses in future studies (compared to monthly disposables used here) may reduce the drop-out rate, by increasing convenience and eliminating the need for maintenance.

Visual performance differences were observed, particularly in low-contrast vision which was reduced by at least one line at distance and near. This may be clinically significant for everyday function. These results highlight the importance of monitoring quality-of-vision outcomes alongside refractive and axial changes.

Further research is primarily needed to better understand the long-term efficacy of this lens, given the initially promising results at 6 months which weren’t evident at 12 months. Direct comparison to a lower defocus profile would also help to determine any dose-response effect.  

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 = 0.001) 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.

Conclusions 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.

[Link to open access paper]