The solution came in the form of DIMS lens, developed in collaboration with Hoya Vision Care and based on the same defocus principles as the DISC lens. Developing the spectacle lens presented an added challenge, commented Prof. To, because “the eye moves behind the spectacle lens and therefore the myopic defocus optics have to be incorporated all over the lens”. The team solved this problem by incorporating many micro-lenses over the surface of the lens, so that the “eye still experiences a constant amount of myopic defocus” as the eye moves around different regions of the lens.
The DIMS lens was tested in a two-year, randomised double-blinded clinical trial with a sample of 160 children aged 8 to 13. The children, who had myopia ranging from 1 to 5 diopters (D), were randomised into two groups: half of the children wore spectacles with DIMS lenses and the other half wore normal single vision spectacles. Prof. Lam comented that by the end of the trial, the average progression in the treatment group was 0.38D, compared with 0.93D in the control group, while the axial length of the eyeball increased by only 0.21 mm in the treatment group compared with 0.53 mm in the control group. Some children in the treatment group showed remarkable individual improvements, with more than 20% experiencing no further myopic progression, compared with only 7.4% in the control group, and 13.9% experiencing no change in axial length, compared with 0% in the control group.
The children in the treatment group found the DIMS spectacles comfortable to wear and they reported good short and long distance vision and good depth perception. The findings are particularly meaningful for those children who would otherwise develop high myopia, who have an additional risk of developing complications such as retinal detachment and glaucoma, which can result in permanent blindness or impairment. For them, early myopic intervention is extremely important.
DIMS spectacle lenses were made commercially available this summer under the brand name MyoSmart. Millions of children worldwide now have another choice to slow the progress of myopia.