Groundbreaking spectacle lens slows myopia progression in children

High myopia can cause complications that may result in permanent blindness or visual impairment. The Defocus Incorporated Multiple Segments (DIMS) Spectacle Lens was newly developed to slow down myopic progression in children. Principal Investigators of this project, Prof. Carly Lam and Prof. To Chi-ho at the School of Optometry, explained this invention.

1. What is the main cause of myopia?

Myopia occurs when the eyeball is too long relative to the focusing power of the cornea and lens of the eye. Light focuses in front of the retina rather than on it, making distant objects appear blurry.

2. How can the DIMS Spectacle Lens provide clear vision and vision correction functions simultaneously.

The DIMS Spectacle Lens comprises of a central optical zone for correcting refractive error (i.e. myopia and astigmatism) and multi-segments of constant myopic defocus surrounding the central zone and extending to mid-periphery of the lens. It provides clear vision and myopic defocus for vision correction simultaneously for the wearer at all viewing distances. The lens makes use of the natural homeostatic mechanism known as ‘emmetropisation’, whereby the eyeball adapts and shapes to receive focused images as it does with normal vision. This is the same mechanism applied in the award-winning Defocus Incorporated Soft Contact (DISC) Lens developed by the research team in 2011 to control the progression of childhood myopia.

3. Please introduce the clinical trial of the DIMS Spectacle Lens.

A total of 160 Chinese children aged 8 to 13, with myopia from 1 to 5 diopters (D), and astigmatism and anisometropia of 1.5D or less, completed a randomised double-blinded clinical trial from August 2014 to July 2017. During the trial, 79 and 81 children were randomly assigned to wear the DIMS Spectacle Lenses (treatment group) and the single vision spectacle lenses (control group) respectively.

4. What were the results of the clinical trial?

Results revealed that the mean myopic progression and the mean increase in eyeball axial length of the treatment group over two years were 0.38D and 0.21mm respectively, whereas the control group recorded 0.93D and 0.53mm respectively. This showed that children wearing the DIMS Spectacle Lenses had significantly less myopic progression by 59%, and less axial elongation by 60%, compared to those wearing the single vision lenses.

In addition to slowing myopic progression, the study showed that wearing DIMS Spectacle Lens halted the progression of myopia in some children. 21.5% of children in the treatment group had no myopic progression whereas only 7.4% of children in the control group had no myopic progression.

5. What are your future plans for the DIMS Spectacle Lens?

With this invention, we are honoured to have won the Grand Prize, Prize of the Legal Company 《Gorodissky & Partners》, Russia, and Gold Medal with the Congratulations of Jury at the 46th International Exhibition of Inventions of Geneva. The DIMS Spectacle Lens will be available in the market this summer.