Study finds permanent benefits of multifocal contact lenses in slowing myopia

Completing ten years of work to stem the tide of myopia, David Berntsen, Golden-Golden Professor of Optometry and chair of Clinical Sciences at the University of Houston College of Optometry, reports that his team’s method for slowing myopia not only works—but lasts.

The original Bifocal Lenses In Nearsighted Kids (BLINK) study showed that children with myopia wearing high-power multifocal contact lenses slow its progression. Now, new results from the BLINK2 Study – which continued after these children – found that the benefits continue even after the lenses are no longer used.

“We found that one year after discontinuing treatment with high-added-power soft multifocal contact lenses in older adolescents, myopia progression returned to normal without loss of treatment benefit,” Berntsen reports in JAMA Ophthalmology. The study was funded by the National Eye Institute of the National Institutes of Health with collaborators from the Ohio State University College of Optometry.

Focus: Major issue

In leading the team at the University of Houston, Berntsen faces a significant challenge. By 2050 almost 50% of the world (5 billion people) will be myopic. This means that if you are not nearsighted and wear glasses, the person sitting next to you may be. Myopia is associated with an increased risk of long-term eye health problems that affect vision and can even lead to blindness.

Since the original study, high addition multifocal contact lenses have been found to be effective in slowing the rate of eye growth, reducing how myopic children become. Because higher amounts of myopia are associated with vision-threatening eye diseases later in life, such as retinal detachment and glaucoma, controlling its development during childhood potentially offers an additional future benefit.

There has been concern that the eye may grow faster than normal when myopia control contact lenses are discontinued. Our findings show that when older teenagers stop wearing these myopia control lenses, the eye returns to the age-expected rate of growth.”

David Berntsen, Golden-Golden Professor of Optometry and Chair of Clinical Sciences at the University of Houston College of Optometry

“These results from the BLINK2 study show that the benefit of myopia control contact lens treatment has a lasting benefit when discontinued at an older age,” said BLINK2 study chair Jeffrey J. Walline, associate dean for research at the College of Optometry, Ohio State University.

Eye science

Myopia occurs when a child’s developing eyes become too long from front to back. Instead of focusing images directly on the retina—the light-sensitive tissue at the back of the eye—images of distant objects are focused at a point in front of the retina. As a result, people with myopia have good near vision but poor distance vision.

Prescription glasses and single-vision contact lenses can correct myopic vision, but they fail to address the underlying problem, which is the eye continuing to grow larger than normal. In contrast, soft multifocal contact lenses correct myopic vision in children while simultaneously slowing the progression of myopia by slowing eye growth.

Designed like a bullseye, multifocal contact lenses focus light in two main ways. The central part of the lens corrects myopia so that distance vision is clear and focuses light directly on the retina. The outer part of the lens adds focusing power to focus peripheral light in front of the retina. Animal studies show that focusing light in front of the retina can slow growth. The higher the reading power, the further in front of the retina the peripheral light is focused.

OPEN once…then twice

In the original BLINK study, 294 myopic children, aged 7 to 11 years, were randomly assigned to wear single vision contact lenses or multifocal lenses of either high power (+2.50 diopters) or medium power (+1.50 diopters). They wore the lenses during the day as often as they comfortably could for three years. All participants were examined at clinics at Ohio State University, Columbus, or the University of Houston.

After three years in the original BLINK study, children in the high-addition multifocal contact lens group had shorter eyes compared to the medium-addition and single-vision groups, and also had the slowest rate of myopia progression and eye growth .

Of the original BLINK participants, 248 continued to BLINK2, during which all participants wore high-addition lenses (+2.50 diopters) for two years, followed by single-vision contact lenses for the third year of the study to see if the benefit remained after stopping treatment.

At the end of BLINK2, axial eye growth returned to age-expected rates. While there was a small increase in eye growth of 0.03 mm/year in all age groups after discontinuation of multifocal lenses, it is important to note that the overall rate of eye growth was not different from the age-expected rate. There was no evidence of faster than normal eye growth.

Participants who were in the original BLINK high-addition multifocal treatment group continued to have shorter eyes and less myopia at the end of BLINK2. Children who switched to high addition multifocal contact lenses for the first time during BLINK2 did not reach the difference of those who wore high addition lenses from the beginning of the BLINK Study, when they were 7 to 11 years old.

In contrast, studies of other myopia treatments, such as atropine drops and orthokeratology lenses designed to temporarily reshape the outermost layer of the cornea, showed a rebound effect (faster than age-normal eye growth) after treatment was stopped.

“Our findings suggest that it is a reasonable strategy to fit children with multifocal contact lenses for myopia control at an earlier age and to continue treatment until late adolescence, when the progression of myopia has slowed,” Berntsen said.