Understanding SEED 1dayPure EDOF soft contact lenses for Myopia Management

Soft contact lenses were first explored for myopia management using designs originally created for presbyopia.^1,2   As evidence grew, this discovery sparked the development of multiple purpose-built myopia-control designs which are now well-studied and commercially available. The SEED 1dayPure EDOF lens is one such example. Developed by the Brien Holden Vision Institute in Sydney, Australia, it may very well be in your practice already as a correction for presbyopic patients. This article explores its application as a myopia management device.

SEED 1dayPure EDOF lenses are daily disposable, extended-depth-of-focus (EDOF) soft contact lenses. The SEED 1dayPure EDOFcontact lens, specifically, incorporates a +1.50 D equivalent amount of defocus.3  The lens material contains a Zwitterionic (overall neutral charge) material known as SIB (SEED Ionic Bond), which is intended to improve material surface stability and maintain high water content. The overall neutral charge also means less deposits are attracted to the lens surface.4

 The optical profile of an extended-depth-of-focus (EDOF) contact lens is different from traditional annular or concentric-ring designs. Instead of using repeated add zones, the lens incorporates a non-monotonic, aperiodic power profile—meaning that the lens power varies in a controlled but irregular way across the optic zone (see Figure 1).⁴ This power profile allows the lens to extend depth of focus while maintaining functional retinal image quality. The result is a broadened range over which the eye can maintain clear vision. By avoiding the sharp transitions found in annular designs, the EDOF design provides a smooth, natural visual experience while still influencing the retinal signals that drive axial elongation.

The SEED 1dayPure EDOF lenses are designed to work primarily through two interconnected mechanisms: manipulating higher-order aberrations (HOAs) to modulate retinal image quality and leveraging the principle of myopic defocus to slow axial elongation. Although the lens does not use discrete add zones like traditional dual-focus or multifocal designs, its optical behaviour ultimately supports the same goal: reducing the hyperopic defocus cues that drive axial elongation.

•  Manipulation of Higher-Order Aberrations (HOAs): The primary engineering principle behind EDOF lenses is the deliberate manipulation of selective HOAs across the optic zone, which is thought to be associated with myopia progression.⁵  The design creates a global change in retinal image quality across both the central and peripheral retina. Not only does this then provide an extended depth of focus, but it also enhances image quality for points that fall on or slightly in front of the retina (myopic defocus), while deliberately reducing image quality for points behind the retina (hyperopic defocus).⁴ 
• Defocus theory: Hyperopic defocus at the peripheral retina is believed to stimulate eye growth. By degrading image quality for these focal points, the SEED 1dayPure EDOF lenses reduce the impact of this hyperopic signal. At the same time, preserving image quality for anterior and on-retina focal points helps create a favourable balance between clear and degraded focus cues. Functionally this acts as an analogue to myopic defocus, encouraging the eye to slow its axial elongation even though the lens does not specifically produce discrete myopic defocus zones.⁶ 

The SEED 1dayPure EDOF lenses have consistently demonstrated efficacy in slowing myopia progression and axial elongation across different populations in multiple studies:

• 1-year randomized clinical trial in India: In a 1-year randomized clinical trial involving Indian children wearing the SEED 1dayPure EDOF lens, myopia progression was slowed by 59%, and axial elongation by 49%, compared with children wearing single-vision (SV) spectacle lenses.⁴  
• 2-year randomized clinical trial in China: In a two-year randomized trial evaluating several soft contact lens designs, the lenses incorporating the same EDOF optical profile as the SEED 1dayPure EDOF slowed myopia progression by 26–32% and axial elongation by 25–27% compared with single-vision contact lenses.⁶  
• 1-year retrospective study in Japan: In a one-year retrospective analysis of children wearing the SEED 1dayPure EDOF lens, the mean change in the refractive progression was −0.23±0.53 D and the mean change in AL was 0.09±0.22 mm. Over 40% of participants appeared to experience no axial elongation.³ 
• 2-year prospective study in Spain: In a 2-year study of Caucasian children wearing the MYLO EDOF lens (which uses the same optical design as SEED 1dayPure EDOF), axial elongation over two years averaged 0.37 mm in the treatment group versus 0.66 mm in the control group. Refractive progression was also slowed by approximately 0.50 D.⁷ 

Across multiple clinical studies, the SEED 1dayPure EDOF soft contact lenses have demonstrated good functional vision and high wearer acceptance, with only minor visual trade-offs reported in some performance measures.

• Subjective vision: In the Spanish study, all questionnaire items—handling, comfort, clarity at distance and near, night-time vision and overall satisfaction—received mean scores of ≥9 out of 10.⁷  In the RCT based in India, 82% of children reported good comfort with the SEED 1dayPure EDOF lens.⁴ 
• Visual acuity: Small reductions in visual acuity have been observed in some studies, but these were typically not clinically meaningful. Visual acuity was lower than with SV spectacles though the difference amounted to less than one line (1–4 letters).6,7  Contrast sensitivity: No significant differences were reported in contrast sensitivity between EDOF lens wearers and SV spectacle lenses.⁷ 

Taken together, emerging evidence suggests that SEED 1dayPure EDOF soft contact lenses may play a role in myopia management, with positive findings observed in different populations and a visual performance profile that appears to be well tolerated by children; however, further research and regulatory evaluation are needed.