E Matthew, an almost four-year-old preschooler, sits in the optometrist’s chair. He is in for his first eye examination. As is the case with most children, especially boys his age, he is busy; his concentration skills are brief at best; he would rather be playing outside or be stimulated by Sesame Street. Big Bird and his other colourful friends are much more interesting than answering the eye doctor’s many questions.
Suddenly, Matthew gets upset when the optometrist covers his right eye. His words “Hey, you are covering my seeing eye” echo across the dimly lit room. There is a long pause. Repeating the test gives the same result---the right eye is the seeing eye; the left eye seems to have gone to sleep. Matthew has now become a newly diagnosed child with amblyopia.
Amblyopia is a decrease in vision in the eye without obvious disease. The most common causes are misalignment of the eye, unequal refractive errors (a need for glasses greater in the one eye than the other), uncorrected high refractive errors and cataracts.
Often the first clue that there may be a problem is a “lazy” eye---an eye that is malaligned, turning in or out. Other risk factors may include a family history of eye problems and also premature birth.
In Matthew’s case there were no previous reasons to suspect any loss of vision in one eye. In fact, both his parents are physicians trained in picking up problems early. In fact, Matthew is my oldest son. Is this a case of the shoemaker’s child going barefoot?
Not according to Doctors Russel Doig and John McWhae, two experts in Calgary, who are kind enough to treat my son. Their point, and the point of the American Academy of Pediatrics and Optometric Societies is that all children should have their vision tested before they enter school, preferably by ages three or four.
Being a paediatrician, I knew how important it was to get my son’s vision checked early in life. That was why we took him in to begin with. We had absolutely no reason to suspect a significant loss of vision in his one eye (the “sleepy eye” as Dr Doig calls it--an appropriate word which helps his little patients understand their own problem better)
In a recent survey, conducted by the University of Alberta, parents of preschool children were asked if they would consider having their child’s vision checked prior to Grade one, and if so, at what age. Out of 592 parents surveyed, 61% of parents would not consider vision testing unless they suspected there was a problem. Only 27% of parents stated they would take their child for routine vision screening within the recommended three-to-four year old range.
Less than one-third of paediatricians regularly provide vision screening for children age three according to a survey done by the American Academy of Pediatrics. This occurs despite the Academy’s formal policy that advises vision screening to begin at three years of age. In fact, in North America, approximately only 20% of children who start school have had routine visual
screening done. Usually it is the teacher who first recognises the problem, alerts the parents, and sometimes it’s too late to treat.
This is unfortunate. The earlier the problem is identified and treated the better. “The development of the visual system is extremely age sensitive,” says Dr James B. Ruben, MD. FAAP, member of the AAP Section of Ophthalmology. “It is a bit like freshly poured concrete. It is mouldable early in life, but as children age, their vision system (the brain) becomes set and cannot be changed.”
Kittens are born with their eyes closed and when researchers stitched one eyelid together, thus preventing it from opening later, they found that if this is done for long enough the eye then becomes blind. The kitten’s brain---and we know now that the same is true for a young child---makes a decision. The decision, essentially, is to not bother any further with the “bad” eye; it gets switched off; ignored.
However, if the problem is identified early (preferably in the preschool age), there is treatment. It involves fitting the child with glasses that correct the refractive error, most often due to an extremely far-sighted eye. That is the relatively easy part. The harder part is to place an eye patch over the good eye, thus forcing the child to use the sleepy eye. This is done for one hour per age---a four year old has to wear this patch for four hours per day, for example. Parents are told to tell the child “we are going to wake up the sleepy eye by pretending you are a pirate”. That strategy works well during Halloween.
Compliance remain a major problem. That is why a recent study done at Johns Hopkins’ Wilmer Eye Institute which involved 47 eye care centres across North America---including the Alberta Children’s Hospital-- looked at an alternative treatment method: instilling atropine drops in the healthy eye, thus temporarily “blinding” the child and forcing them to use the weak eye. It works well, but so far has not caught on yet--- ophthalmologists still prescribe patching 97% of the time.
Kentucky was the first State that mandated mandatory eye exams at an earlier age. Recently Massachusetts, and California were added to the list. In Alberta, the College of Optometrists are doing their best to work with the Government to address this preventable cause of blindness. Unfortunately, it may have become a political battle---should public health nurses do it or Optometrists?
Meanwhile, in March 2002, the AAP published a position statement on the use of photo screening for children’s vision screening. It is worth reading: Pediatrics Vol 109 No 3 March 2002 p 524.
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