Bifocal contact lenses are no longer just for aging eyes.For myopic children as young as 7 years old, multifocal contact lenses with high-dose reading ability can significantly slow the progression of myopia, new research has found.
In a three-year clinical trial of nearly 300 children, bifocal contact lens prescriptions with the highest near working correction slowed myopia progression by 43 percent compared to single vision contact lenses.
Although many adults in their 40s took time to adjust to their first multifocal contact lens prescription, the children in the study who used the same commercially available soft contact lenses had no vision problems despite their strong corrective ability.Multifocal lenses for myopic patients correct clear distance vision and “increase” focal length for near work that challenges middle-aged eyes.
Bifocal Contact Lenses
“Adults need multifocal contact lenses because they can no longer concentrate on reading,” said Jeffrey Walling, a professor of optometry at Ohio State University and the study’s lead author.
“Even though kids wear multifocal contact lenses, they can still focus, so it’s like giving them regular contact lenses. They’re easier to fit in than adults.”
The study, called BLINK (Bifocal Lenses for Children with Myopia), was published today (August 11) in JAMA.
In myopia, or nearsightedness, the eye grows into an elongated shape in an uncoordinated manner, the reason for which remains a mystery.Animal studies have given scientists the potential for contact lenses to control eye growth by using the reading portion of a multifocal contact lens to focus some light in front of the retina — the layer of light-sensitive tissue at the back of the eye — to slow eye growth.
“These multifocal contact lenses move with the eye and provide more focus in front of the retina than glasses do,” said Waring, who is also associate dean for research in Ohio State’s School of Optometry.”And we want to slow down the growth rate of the eyes, because myopia is caused by the eyes growing too long.”
This study and others have already made progress in the treatment of myopic children, Waring said.Options include multifocal contact lenses, contact lenses that reshape the cornea during sleep (called orthokeratology), a specific type of eye drops called atropine, and specialty glasses.
Myopia is not just an inconvenience.Myopia increases the risk of cataracts, retinal detachment, glaucoma, and myopic macular degeneration.All of these conditions can cause vision loss, even with glasses or contact lenses.There are also quality-of-life factors – less nearsightedness improves the chances of laser surgery to successfully correct vision and not be disabling when not wearing aligners, such as when you wake up in the morning.
Myopia is also common, affecting about one-third of adults in the U.S., and is becoming more common — as the scientific community believes that children are spending less time outdoors than they did in the past.Myopia tends to start between the ages of 8 and 10 and progress to around age 18.
Walline has been studying the use of children’s contact lenses for many years and has found that in addition to being good for vision, contact lenses can also improve children’s self-esteem.
“The youngest myopic child I’ve studied was seven years old,” he said.”Not all 25-year-olds can tolerate contact lenses. About half of 7-year-olds can reasonably fit in contact lenses, and almost all 8-year-olds can.”
Bifocal Contact Lenses
In this trial, conducted at The Ohio State University and the University of Houston, myopic children ages 7-11 were randomly assigned to one of three groups of contact lens wearers: a monovision or multifocal prescription with a 1.50 diopter increase in the median reading or High add 2.50 diopters.Diopter is the unit of measurement for the optical power required to correct vision.
As a group, participants had an average diopter of -2.39 diopters at the start of the study.After three years, children who wore high-value lenses had less progression of myopia and less eye growth.On average, children who wore high-add bifocals grew their eyes 0.23 mm less at three years than those who wore single vision.Moderate lenses do not slow eye growth any more than single vision lenses.
The researchers realized that the reduction in eye growth needed to be balanced against any risks associated with enabling children to accept strong reading skills long before children needed this level of correction.There was a two-letter difference between monofocal lens wearers and multifocal lens wearers when testing their ability to read gray letters on a white background.
“It’s about finding a sweet spot,” Waring said.”In fact, we found that even high added power did not significantly reduce their vision, and certainly not in a clinically relevant way.”
The research team continued to follow the same participants, treating them with high-attach bifocal lenses for two years before switching them all to single-vision contact lenses.
“The question is, we slow down the growth of the eyes, but what happens when we take them out of the treatment? Do they go back to where they were originally preprogrammed? The durability of the treatment effect is what we’re going to examine,” Walline said. .
The research was funded by the National Eye Institute, part of the National Institutes of Health, and supported by Bausch + Lomb, which provides contact lens solutions.
Post time: Jul-17-2022
