Home › Science › Health › Bifocal contact lenses can prevent myopia in children from getting worseThe results of a new clinical trial may give more hope to children with myopia.The study found that children as young as 7 years old who regularly wore strong bifocal contact lenses experienced less worsening of their myopia than those who wore less powerful or single-focus lenses over a three-year period.This suggests that these children may be able to preserve more vision into adulthood.Myopia is one of the most common vision conditions to affect people under 40 years of age.While the causes of myopia are complex, both genetics and the environment are believed to play an important role.In particular, studies have suggested that too much schoolwork and reduced outdoor play before preschool can contribute to myopia, likely because children spend too much time concentrating on nearby objects.Nearsightedness tends to appear around age 7 and continues to get worse until adolescence, on average.Doctors have been looking at ways to slow its progression as much as possible during this time, including specialized eye drops and bifocals and glasses.But this latest experiment, known as the bifocal lens study in myopic children, or BLINK, is the first to empirically compare whether soft, high-powered bifocal contact lenses are better for myopic children than other types of lenses. .When measuring people's myopia or hyperopia (difficulty seeing up close), ophthalmologists rely on a metric called diopter, better known popularly as "degree".Relative to normal vision, people with myopia have negative diopter.While both monofocal and multifocal glasses can correct a person's vision so that they can accurately see things that are far away, multifocals also add more diopters, which can improve vision for people who have other difficulties.Bifocals are the most common type of multifocals.On the downside, multifocal glasses tend to be more difficult to physically adjust than single vision glasses, and they limit a person's field of vision more.In the trial, nearly 300 children ages 7 to 11 were randomly assigned to receive one of three types of contact lenses.Children received high-power bifocals (with the addition of 2.5 diopters), medium-power bifocals (1.5 diopters), or monofocal lenses.Then they were observed for the next three years.The main finding of the study, published in the journal JAMA, was that children who wore the strongest bifocal lenses had a smaller advance in their nearsightedness (an average of -0.60 diopters), while children who had single vision lenses experienced a shorter improvement. greater advance of the condition (an average of -1.05 diopters).And while bifocals are known to be difficult for adults to fit in at first, with many experiencing symptoms such as headaches, migraines and balance problems, children who wore the strongest corrective lenses reported no additional adverse effects, likely because their eyes are better able to compensate.“The long-term implication is that children who wear multifocal contact lenses will be less nearsighted as adults, which will ultimately make them less likely to experience vision complications like retinal detachment, glaucoma, and myopic maculopathy. vision even with eyeglasses or contact lenses due to the large amount of myopia),” the study’s lead author, Jeffrey Walline, professor of optometry at Ohio State University, said in an email.Walline and her team plan to continue following the children in this study longer, having them continue to wear bifocals for two years before switching to single vision lenses.The hope is that these improvements will last even when they stop wearing bifocals.But, according to Walline, the results of this study and others show that doctors should try to do everything in their power to slow the progression of myopia and that parents and children should be informed in advance about treatments available today.Currently, an estimated one-third of Americans have myopia.In China, most children are nearsighted.At the same time, although the children in this study were able to use bifocals without problems, it is likely that this strategy does not work for everyone.In that case, Walline added, there are still other options, such as orthophonatology (the use of specialized lenses worn at night that temporarily reshape the cornea) or low-concentration atropine eye drops, which dilate the pupils and can prevent the eyes from stretching.