More children are being diagnosed with nearsightedness, but experts aren’t sure why.
Helping to prevent nearsightedness in children may be as simple as urging them to spend more time outside, some experts say.
Possibly due to changing habits among children — spending more time reading in dim light and spending more time indoors than those of past generations — doctors are seeing an increase in the number of cases of nearsightedness, also known as myopia.
Children’s Hospital of Pittsburgh of UPMC recently opened a Myopia Treatment Center to meet the growing demand.
Nearsightedness is a condition in which vision gets blurred when viewing an object at a distance. In some countries such as China nearsightedness has reached epidemic proportions with as much as 80% of the population being affected.
For a person with normal vision, the light ray reflecting from an object passes through the cornea and gets focused directly on the surface of the retina.
But for those with myopia, the light rays get focused at a point in front of the retina rather than on its surface. This is because the eyeball becomes elongated, making distant objects seem blurry.
Ken Nischal, Children’s chief of the Division of Pediatric Ophthalmology, said there is a 4 percent increase in myopia among children globally. In the six years since he has been with the hospital, he has seen a rise in the number of children with the condition.
“Myopia is often a result of the eyeballs being longer than they should be. If left untreated, severe myopia in adulthood can lead to retinal detachment, premature cataracts and glaucoma,” he said.
The new center, Dr. Nischal said, is focusing on prevention, study and treatment of myopia. “It will also be a consolidated treatment center where appropriate therapy, education, information and surveillance for nearsightedness will be available under one roof,”
A 2016 report by the National Center for Children’s Vision and Eye Health states that 4 percent of children ages 6 to 72 months have myopia. Another 9 percent of older children (ages 5 to 17 years) have myopia, or nearsightedness in the United States.
In 2011, Children’s Hospital saw 5,500 patients with myopia; in 2016, that number rose to a whopping 18,500.
Dr. Nischal said one reason for the rise is that the hospital overall is seeing a higher number of patients over the years.
He primarily blamed the growing number of cases on kids trying to see or read in dim light, and not heavier use of technology. “You are not going to be able to pull children away from their iPads and such,” Dr. Nischal said. “But what is often ignored is the lighting condition in which they read. When you read close up all the time, particularly in dim light, the brain assumes it is better to be nearsighted so as to reduce the pressure of focusing for near.”
He advises parents to ensure that reading time in dim light be reduced.
“Ensure the light is over the shoulder on the object they are reading. Switching off the lights and reading under cover is also not good. Dim lights stimulate the eyes to grow,” he said.
Wadih Zein, staff clinician at the National Eye Institute in Bethesda, Md., said a number of genetic and environmental factors are at play as they relate to myopia.
“Children these days spend more time doing near tasks [reading, being on their iPads or iPhones] than what was required of generations in the past. But we can’t say that it is a cause for myopia, although it is definitely a factor,” Dr. Zein said.
There is, however, some debate on near-work activities as a factor in developing myopia.
Leslie G. Hyman, vice chair of research at Wills Eye Hospital in Philadelphia, believes the specific causes for the rise in myopia are unknown.
“No studies to date have found more television or use of newer technologies to be associated with an increase in myopia. For many years many have assumed that spending more time in near-work activities leads to an increase in myopia, and there are studies that have found an association between reading more books and myopia. However, results of studies that have investigated the relationship between myopia and near work have been inconsistent,” Dr. Hyman said.
But there is something that all experts agree on as far as myopia is concerned: spending more time outdoors.
Dr Laura Nennig with Eyecare Associates of Lees Summit noted “The one factor found in a number of studies to be protective for developing myopia is spending more time outside. Children who spend more time outdoors are less likely to develop myopia than children who spend more time indoors even when we factor in gaming and other devices.”
“We don’t yet understand exactly why spending more time outdoors helps to prevent myopia. There has been much interest in identifying the specific reasons and investigators have explored various possibilities including sunlight [possibly vitamin D], and use of the eyes [looking at objects far away and close by] but the answers remain unclear,” said Dr. Nennig.
Other advice Dr. Nennig has for parents is to ensure that children get adequate sunlight.
“Even if it is not possible to let them play outside, encourage them sit by a window where they can get more sunlight. An Australian study reports at the International Specialty Lens Meetings found that chances of nearsightedness increases when exposure to sunlight is less than two hours a day,” Dr. Nennig said.
Dr. Nennig may be right. A study published in JAMA Ophthalmology, an international peer-reviewed journal for ophthalmology, suggests that lack of exposure to sunlight may be a cause of the reshaping of eye and several disorders associated with it.
Dr. Zein of the National Eye Institute said of the many environmental factors at play as far as myopia is concerned, the ones that we know about are reading time and inadequate exposure to sunlight. “Reducing the former and increasing the latter will definitely help decrease the progression rate of myopia,” said Dr. Zein.
Dr. Nennig also notes that there are new therapies that are being put forward to prevent myopia including the use of special drops, bifocal contact lenses and corneal reshaping lenses. “Our office has been using a corneal reshaping technology call CRT for several years with good success. We recently had a 12 year old who heard about us from Bejing, China who came to Lees Summit for CRT treatment and she no longer needs to wear glasses and is 20/20 in each eye.” Dr. Nennig added “some of our office attends the International Myopia Control meeting every year so we can bring these new technologies and practices to our patients.”
Preventing, understanding nearsightedness
How to restrict screen time
- Avoid use of screen media other than video-chatting for children younger than 18 months
- For children ages 2 to 5 years, limit screen use to 1 hour per day.
- For children ages 6 and older, place consistent limits on the time spent using media
Source: American Association of Pediatrics
How to recognize whether your child has myopia
- The child asks to sit at the front of the classroom.
- He or she moves very close to the TV or movie screen.
- The child lacks interest in sports or other activities that require good distance vision.
Symptoms of myopia
- Blurred vision.
- Squinting and frowning when viewing an object.
- Frequent headaches.
- The child holds books or other objects close to his or her face.