Preliminary results for a novel EDOF soft contact lens

Paper title: Center-for-Near Extended-Depth-of-Focus Soft Contact Lens for Myopia Control in Children: 1-Year Results of a Randomized Controlled Trial

Authors: Elizabeth Shen^1-3, Hsiao-Sang Chu³,  Han-Chih Cheng^1,2 and Tzu-Hsun Tsai⁴

1. Department of Ophthalmology, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, Taipei, Taiwan (R.O.C.).

2. School of Medicine, Tzu Chi University, Hua-Liang, Taiwan (R.O.C.).
3. Department of Ophthalmology, National Taiwan University Hospital, College of Medicine, National Taiwan University, 12F, No 7, Zhongshan S. Rd., Zhongzheng Dist., Taipei, 10002, Taiwan (R.O.C.).
4. Department of Ophthalmology, National Taiwan University Hospital, College of Medicine, National Taiwan University, 12F, No 7, Zhongshan S. Rd., Zhongzheng Dist., Taipei, 10002, Taiwan

Date: Aug 2022

Reference: Shen EP, Chu HS, Cheng HC, Tsai TH. Center-for-Near Extended-Depth-of-Focus Soft Contact Lens for Myopia Control in Children: 1-Year Results of a Randomized Controlled Trial. Ophthalmol Ther. 2022 Aug;11(4):1577-1588.

[Link to open access paper]

Increased accommodative lag for near activities has been suggested as a risk factor for myopia in children with the resulting hyperopic peripheral defocus acting as a stimulus for axial length growth within the eye and myopia progression.¹ The basis of extended depth of focus (EDOF) contact lens designs is to reduce the accommodation needed for close work and induce myopic defocus at the periphery of the retina. For an in-depth explanation of EDOF lens design, see here.

This prospective, randomised double-masked study investigated the safety and efficacy of a novel centre-for-near EDOF soft myopia control contact lens design for reducing myopia in children. The lens incorporated a central under-correction zone to reduce on-axis hyperopic defocus during near work with a surrounding outer zone containing over and under - correction for distance focus.

Myopic children aged 9 to 14yrs (40 male and 32 female) were recruited from the National Taiwan University Hospital and Taipei Tzu Chi hospital. They had healthy eyes with myopia between -1.00 to -8.00D, astigmatism of ≤ 1.75D and had shown myopic progression of at least 0.75D in the previous year. Cycloplegic refraction, axial length, keratometry and slit lamp examination were performed at weeks 1,4,13 and at each 13-week interval, up to a year. Each eye was randomly fit with either the novel EDOF lens or single vision aspheric placebo contact lens of the same material. Both lenses were single-use daily disposable and the children were asked to wear for at least 8hrs per day, 5 days a week for a year. Wear schedule compliance and ocular concerns were assessed via regular questionnaires and patient-recorded diary entries. Primary outcome was changes in SER over a year and secondary outcome was change in axial length.

The full year study was completed by 67 children with a mean age of 12. The average wear time was 11.2hrs per day and no adverse responses related to lens wear were reported. The mean SER and axial length changes at 52 weeks were found to be significantly lower with the treatment lens wear than with the control lens (-0.70 ± 0.49D v -0.88 ± 0.51D and 0.34 ± 0.19mm v 0.38 ± 0.19mm, respectively), representing 10.5 and 20.5% respective savings. The SER changes were shown to be significantly associated with wearing the EDOF lens, while axial changes were associated SER at baseline and age, but not lens type. 

This novel EDOF lens design was able to provide slowing of refractive and axial length changes and safety for wear.

These results are from one year wear only so far, which makes it hard to predict the long-term efficacy of this lens. However, there is potential for adding it to the growing portfolio of myopia control contact lenses available to eyecare practitioners. 

The degree to which this EDOF lens design was able to slow myopia progression initially appears less than other lens types currently available.

Differences in study designs (contralateral eye studies v control studies, for example), participant age, ethnicity and progression rates prior to participation could all impact results.

Further studies are needed to assess long-term efficacy, rebound effects and effects on amplitude of accommodation.

Title: Center-for-Near Extended-Depth-of-Focus Soft Contact Lens for Myopia Control in Children: 1-Year Results of a Randomized Controlled Trial

Authors: Elizabeth P Shen, Hsiao-Sang Chu, Han-Chih Cheng, Tzu-Hsun Tsai

Purpose: This study aimed to assess the safety and efficacy of a novel extended-depth-of-focus (EDOF) soft contact lens for myopia control in children.

Methods: A prospective, multicenter, randomized, double-masked, placebo-controlled, contralateral-eye comparison clinical trial was conducted in 72 children (40 male and 32 female) aged 9 to 14 years, with each eye randomly selected to wear either an experimental EDOF contact lens or a single-vision control lens at least 8 h per day, 5 days a week, for 52 weeks. Each contact lens was worn and then replaced daily. Measurements including best-corrected visual acuity, spherical equivalent refractive error (SER), axial length (AXL), and keratometry were performed at weeks 1, 4, and 13, and every 13 weeks thereafter for 52 weeks. The primary outcome measure was the change in SER, measured using cycloplegic auto-refraction. The secondary outcome measure was the change in AXL.

Results: At week 52, the mean change in SER was significantly lower with the experimental lens (-0.70 ± 0.49 D) than with the control lens (-0.88 ± 0.51 D; P < .001). The mean AXL elongation was significantly lower with the experimental lens (0.34 ± 0.19 mm) than with the control lens (0.38 ± 0.19 mm; P < .001). The EDOF lens reduced AXL and myopia progression by 10.5% and 20.5%, respectively. The change in SER, but no AXL, was significantly associated with EDOF lens wear in adjusted multivariate regression analysis. Reported adverse events did not differ significantly between the two lens types.

Conclusions: The results of this 1-year clinical trial demonstrate that the experimental EDOF soft contact lens slows myopia progression and reduces AXL elongation in children compared with a single-vision contact lens

[Link to open access paper]