Wednesday, August 12, 2020
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Usually multifocal lenses are recommended for adults aged 40 and over. But myopic children between the ages of seven and eleven should also benefit from it. This is what researchers find out in a three-year study with almost 300 children.
Multifocal contact lenses could help reduce the progression of myopia in children. At least that is the result of a study, report about the scientists in the journal “Jama”. This could be especially important because myopia is not just annoying in everyday life, but can also be a risk factor for serious eye diseases such as cataracts or retinal detachment – the more the earlier it begins and the stronger it is.
Multifocal contact lenses, also known as multifocal lenses, are actually mainly used by people aged 40 and over who develop presbyopia and are looking for an alternative to varifocal glasses. The contact lenses enable sharp vision near and far – and, in contrast to varifocals, are independent of the viewing direction. Several studies have already shown that nearsighted children could also benefit from these lenses – a result that is now underlined by the current clinical study by the US Ohio State University and the University of Houston.
Three groups, three results
For the Blink study (“Bifocal Lenses In Nearsighted Kids”), a team led by ophthalmologist Jeffrey Walline divided 287 myopic children between the ages of seven and eleven into three groups: one group wore normal lenses, the second multifocal soft lenses with one Power of plus 1.5 dioptres and the third group of lenses with a power of plus 2.5 dioptres. Over a period of three years, the children should wear the respective lenses as often as possible during the day.
At the end of the study period, nearsightedness (myopia) was the least advanced in the group with the powerful multifocal lenses: only 0.60 diopters. It was 0.89 diopters in the medium power group and 1.05 diopters in the simple lens group.
Lenses prevent the eyes from growing
At the same time, the powerful multifocal lenses slowed down eye growth: in myopia, the eyeball is too long. Rays of light that fall into the eye do not then form their focal point exactly on the retina, i.e. the retina, but in front of it. As a result, those affected have good near vision, but see things further away that are out of focus or blurred. In the group with the strong contact lenses, the eyeball grew in length by 0.42 millimeters during the study period, in the children with the weaker multifocal lenses by 0.58 millimeters and in those who wore normal lenses by 0.66 millimeters.
In addition, unlike adults, children with the powerful multifocal contact lenses would have no difficulty adapting them, emphasizes study leader Jeffrey Walline: “Children can still focus their eyes even though they wear multifocal contact lenses. So it is as if they were fitted with normal contact lenses. They fit much easier than adults. ” A follow-up study should now clarify how long multifocal lenses should ideally be worn and how discontinuation affects myopia.
Well done investigation
For Wolf Alexander Lagrèze, head of pediatric ophthalmology at the University Eye Clinic Freiburg, the Blink study is a “well-planned, carefully executed and well-controlled” study. The observed effect of multifocal lenses is not new, but the authors used a three-armed approach compared to previous studies. “In this way a dose-effect relationship can be investigated”, explains Lagrèze, who is also a member of the German Ophthalmological Society (DOG), in an independent classification. And that effect was most clearly pronounced in the study with the strong multifocal lenses.
According to Lagrèze, such lenses are another option for treating progressive myopia in children. Furthermore, so-called orthokeratological contact lenses have been used successfully for some time. These are worn overnight and reshape the epithelium, i.e. the top cell layer of the cornea. Their effect strength is not inferior to that of the multifocal lenses. To do this, orthokeratological lenses would have to be worn every night: “If, for example, you have to take a few nights out because of eye irritation or conjunctivitis, the nearsightedness is partially there again.”
Three effective ways
Treatment with atropine drops is also effective. “Low-dose atropine is the most effective intervention and is also uncomplicated to use: parents always put a drop in each child’s eye before going to bed, for example to brush their teeth,” explains Lagrèze. All three options – multifocal lenses, orthokeratological lenses or atropine drops – are suitable for slowing down the progression of myopia in children: Ultimately, the decision on the specific method depends primarily on the child in question, says the ophthalmologist: “Need for contact lenses the children are highly motivated, while others may not like eye drops. ” The authors of the current study also see multifocal lenses as an addition to the existing range of treatments.
Lagrèze warns, however, not to overestimate the figures quoted by the authors, according to which half the world’s population will be myopic by 2050. “Such predictions far into the future are difficult,” he explains. In Europe the numbers are not as dramatic as in Asia, especially in Germany the rate of myopia in prescription glasses has remained constant among young people over the past 16 years. Nonetheless, there is a connection between myopia and increased vision at close range, for example due to the increasing use of smartphones, tablets and the like, according to Lagrèze: “Accordingly, longer reading at a distance of less than 30 centimeters should be avoided.”
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