Children at risk for CVS from computer use, study says

Issue: May 2002

ByDiane M. Watson

With computer use becoming more prevalent than ever in today’s society, people are becoming more aware of the potential visual problems that may arise from viewing a computer screen for extended periods of time. Practitioners are prescribing computer glasses, employees are complaining of headaches and neck aches from computer use and people are paying more attention to the ergonomics of the computer workstation.

As concerns about computer use being linked to visual problems in adults become increasingly common, practitioners are turning their attention to the effect computer use may be having on the visual systems of children. Some researchers are worried that children who use computers frequently may be at a higher risk for developing myopia and other visual problems.

“We know for sure that adults who sit in front of a computer more than 4 hours a day do develop signs and symptoms of accommodative spasm and focusing difficulties,” said Pia Hoenig, OD, chief of the binocular vision clinic at the University of California, Berkeley, School of Optometry. “We’ve known for more than 10 years that these responses to prolonged near work have existed in adults. A number of studies and questionnaires have shown what is now coined as computer vision syndrome (CVS). I was involved in some of those and wondered whether it occurred in children as well as adults.”

CVS in children: a study

Some initial study findings by Dr. Hoenig and her team indicate a correlation between children who work many hours at a computer and an overactive accommodative system (accommodative spasm or accommodative lead), distance blur, clinical findings of premature myopia and other stresses on the visual system. “One of the things that came out of our study was that children do experience the same CVS as we found previously in adults,” she said. “They don’t always verbalize the symptoms, but when you evaluate it and do the testing, you will see those same findings in children — accommodative difficulties and accommodative infacility.”

The study was based in seven different offices nationwide whose doctors had a pediatric base, who were accustomed to working with children and performing binocular vision evaluations and who also were familiar with the Monocular Estimated Method (MEM) and the Prio tester (Prio Corp., Santa Cruz, Calif.). Phase 2 has been completed and more than 500 children were involved. Dr. Hoenig said that the data from children who had poor vision in one eye (amblyopia) or the tendency for eye turn (strabismus) were eliminated from the study before the final analysis. The study included children who were “using both eyes together, were fully corrected to 20/20 and were wearing their appropriate correction for distance,” she said. “It eliminated any other findings that would interfere with and contaminate the near response.”

As part of the study, a questionnaire was developed for the doctors to use during the intake, which requested information on how many hours a child spent on close work, computer games and reading, Dr. Hoenig said. The doctors completed a detailed binocular vision evaluation, and results were submitted to Dr. Hoenig, who compiled the statistics.

Dr. Hoenig said that they will continue to provide complete binocular vision evaluations “for all our school age children that pass through our centers and pay particular attention to their accommodative findings,” she said. “The next logical step for us is to follow the initial group of children for a couple of years and monitor their long-term changes in refractive errors and accommodative status. It is also of interest to us to evaluate if those factors change with the intervention of either visual therapy or the prescription of a near-addition lens.”

Ken Burke, OD, a study investigator, said that one of the important results found is that some children are using computers before they have the necessary motor skills. “Many more children are on computer screens at earlier ages — many of these children are on computers before they develop some of their fine motor skills,” Dr. Burke said. “Sometimes kids are being subjected to computer screens before they’ve actually had a chance to mature at that level.”

Ergonomics and children

Another important factor to consider is the ergonomics of the computer workstation, said Dr. Burke, as children are often using their parents’ computers and therefore can experience physical problems they would not encounter otherwise.

“Children often work on screens that have been set up for adults,” he noted. “Therefore, they may be too close to the screen, the angle of the screen sitting in front of them will be different because they’re smaller and they’re not sitting high enough. Their arms are shorter, so they may be closer to the screen than adults. Many adults who come into my office don’t even know the proper angle of the screen or the proper distance. And if they don’t know, the kids don’t know.”

Dr. Burke added that the same pixels on a computer screen that cause overfocusing problems in adults can have an even greater detrimental effect on a child whose visual system is still developing. “A child still has a fairly flexible visual system — a visual system that will be influenced by environmental factors — and will be even more influenced by a computer screen than an adult,” he said. “Most adults have gone through their visual stages of development and have made their adaptations. But children are very pliable and are definitely more influenced by the undesirable effects of the screen, including lag of accommodation, overconvergence and the positively charged field (EMF) emitted from the screen.”

Study: computer use not linked to myopia

The Orinda Longitudinal Study of Myopia, a cross-sectional study conducted between 1991 and 1995, involved 365 myopic and emmetropic eighth-grade children in Orinda, Calif. Donald O. Mutti, OD, PhD, one of the investigators in the study headed by Karla Zadnik, OD, PhD, said that several factors were evaluated, such as ocular development and refractive error as well as environmental variables, such as time spent reading for pleasure, watching TV, playing video games, working on the computer and playing sports. Also considered were genetic variables, most notably whether or not the parents were nearsighted.

“We found that myopic kids study more and read for fun more, but we did not see differences with respect to watching TV, playing video games or working with the computer,” Dr. Mutti said. “So while people think that using computers might put kids at risk for developing myopia, our study makes me think probably not.”

Genetics the main factor

What appears to be the primary factor for children developing myopia, said Dr. Mutti, is whether a child has one or both parents who are nearsighted. “We found that near work is a significant but very small factor when compared to myopia in the parents,” he said. “If we try to compare the two factors and determine which seems to be the most significant, myopic parents far outweighs any contribution from near work. Kids would have to do about twice as much near work as they already do to equal the contribution of one nearsighted parent.”

Dr. Mutti said that the study did not indicate that a child with myopic parents had an increased risk of developing myopia from near work. “We’ve looked at that over and over again, and we don’t see any extra risk in near work in kids who have myopic parents,” he said. “A lot of people have theorized that the way myopic parents make kids myopic is by contributing some sort of genetic susceptibility to the environment. We don’t see any evidence for that. The little contribution from near work is the same whether you have zero, one or two nearsighted parents. Near work is near work. And myopic parents are independent from that.”

The researchers have not yet studied whether or not existing myopia progresses more quickly when coupled with a large amount of near work on the computer, Dr. Mutti said, but they hope to analyze their data within the next year or so. “Probably the next thing we’ll look into is the risk of becoming myopic for the first time,” he said. “Probably the last thing we’ll do is look at progression, although that is a worthwhile thing to look at. This current study just compared myopes to non-myopes.”

While he does not see an increased risk of myopia through computer use, Dr. Mutti said computer glasses should be recommended for children who use the computer frequently. “The recommendations for computer glasses are all based on making the child comfortable,” he said. “Computers can be a source of visual discomfort. It is a very real thing and can be a serious problem. In terms of recommendations, I think that recommendations about where to place the keyboard, how to arrange the lighting, what kind of working distance a person uses and having a prescription if needed should be addressed. But worrying whether their computer use is going to drive them into nearsightedness … I don’t see evidence for that.”

For Your Information:

Pia Hoenig, OD, is chief of the binocular vision clinic at the University of California, Berkeley, School of Optometry. She may be reached at 390 Minor Hall #2020, Berkeley, CA 94720-2020; (510) 642-2020; e-mail: Pia@sonic.net.

Ken Burke, OD, may be reached at 175 Main St. South, Woodbury, CT 06798-3405; (203) 263-3391; fax: (203) 263-3390.

Donald O. Mutti, OD, PhD, may be reached at the Ohio State University School of Optometry, 42 Fry Hall, 338 W. 10th Ave., Columbus, OH 43210; (614) 247-7057; fax: (614) 247-7058.