CHICAGO – A dual focus contact lens was found to significantly reduce myopia progression and axial elongation at 1, 2 and 3 years when compared to a single vision lens, according to a presentation here at the American Academy of Optometry meeting.
Paul Chamberlain, BSc(Hons), at an academy-sponsored press conference, presented 3-year results of a study evaluating the efficacy of a dual focus contact lens (DFCL) compared to a single vision lens, both made of omafilcon A, to slow the rate of myopia progression.
Study subjects were between the ages of 8 and 13 years and evaluated at one of four investigational sites in this prospective, randomized, double-masked, controlled study, said Chamberlain, who is senior manager of clinical research at CooperVision. Seventy wore the DFCL, and 74 wore the Proclear (CooperVision) single vision lens as a control.
At 1 year, children wearing the control lens experienced “just over half a diopter of progression,” while the dual focus group progressed less than one-fourth of a diopter, Chamberlain said.
“In year 2, the dual focus group mirrors year 1, about 0.2 D,” he said. “In the control group there’s slowing of myopia progression – just over half a diopter difference – perhaps due to them getting older. In year 3, there was a little bit of slowing in the dual focus. In the Proclear group the rate was about the same.”
When a statistical model is applied, adjusting for differences in age, ethnicity and gender, “it doesn’t change the effect too much,” Chamberlain added.
“In axial length growth, you want to see a mirror image of this, where the eyeball is growing in a similar effect,” he continued. “We do indeed see that.”
The dual focus groups grew by 0.1 mm in year 1 and by 0.24 mm in year 2. The Proclear group grew by 0.15 mm in year 1 and by 0.32 mm in year 3.
According to the study abstract, the DFCL reduced myopia progression by 59% at 1 year, 54% at 2 years and 52% at 3 years, and axial elongation by 58%, 50% and 45%, respectively, when compared to the single vision lens.
“There were good correlations between change in refractive error and change in eyeball growth,” Chamberlain said.
He said it was no surprise that geographic location, age and gender influenced the change in myopia, “but the myopia control effect was consistent despite all these factors. It worked across different sites, age groups and genders. Baseline myopia also had no effect, nor did wear time. But everyone wore the lenses a lot.”
Chamberlain summarized the results: “This proves that controlled retinal defocus slows axial elongation in children. It shows myopia control of over 50% that can be maintained for a number of years. The results are generalizable across location, age, gender and baseline myopia.” – by Nancy Hemphill, ELS, FAAO
Chamberlain P, et al. Efficacy of a dual focus contact lens and factors influencing myopia progression in a 3-year trial. Presented at: American Academy of Optometry meeting; Chicago; Oct. 10-14, 2017.
Disclosure: Chamberlain is senior manager of clinical research at CooperVision. CooperVision supported this study.