Did you know that Amblyopia, or “lazy eye” is the leading cause of vision problems in children? It affects between two and four percent of all children. According to a new study, treating lazy eye is more likely to be successful the younger the child.
Amblyopia, commonly known as “lazy eye”, is a condition that occurs when one eye has reduced vision that cannot be correctable by glasses or contact lenses and is not due to any eye disease. The study also revealed that treatment for older children may be more beneficial than once thought.
Researchers reviewed data on nearly 1,000 children treated for amblyopia. They found that children between the ages of three and seven were much more responsive to treatment than kids between seven and 13, especially in moderate to severe cases.
Children who were older achieved less improvement, but they did get somewhat better. In a few cases significant gains in vision were noted.
“Earlier is still better, but you still can treat late,” said study co-author Dr. Michael Repka, an ophthalmologist at Johns Hopkins University in Baltimore, Maryland.
A lazy eye is caused either by shortsightedness in one eye, or a misalignment of the eye that affects vision. If the condition is left untreated, the brain will eventually begin to ignore the images from the lazy eye, leading to permanent vision problems.
Treatment begins by first addressing any underlying eye conditions that are responsible for the poor vision through surgery, eye exercises or eyeglasses. Next, the good eye is covered with a patch for two hours a day or given vision-blurring eye drops to force the weaker eye to work. The treatment has no significant side effects and with it, “85 percent of children get to 20-30 vision or better,” said Repka.
To see whether age makes a difference in how successful treatment will be, he and his colleagues in the multi-institution Pediatric Eye Disease Investigator Group reviewed the results of four previous studies that included 996 children. The kids were divided into three groups: ages three to five, five to seven and seven to 13. They were also separated into two categories, moderate and severe, depending on the quality of vision in their affected eye.
Younger children showed a better response to treatment in both moderate and severe cases of lazy eye. Among moderate cases, children aged three to five improved their vision by 39 percent more than the oldest children and the kids between five and seven improved their vision 46 percent more. Measuring vision improvements by a scale known as logMAR lines, which roughly reflects rows on a standard eye chart, kids between three and five gained an average of 2.29 lines, kids five to seven gained 2.41 lines and kids seven to 13 gained 1.65 lines. More dramatic differences were observed in children with a severe lazy eye, although the authors caution that the study did not include many children with severe disease so the numbers may not be broadly representative.
In that category, children in the youngest age group improved their vision, on average, by 4.16 lines of visual acuity — more than twice as much the oldest children who gained 1.99 lines. Despite the advantage of earlier treatment, Repka observed that the benefits of the treatment for older children were better than previously thought. “A group that we didn’t think is treatable is moderately treatable,” he said.
An eye exam by a pediatrician or the 20/20 eye chart screening is not adequate for the detection of amblyopia. According to lazyeye.org, the most important diagnostic tools are the special visual acuity tests other than the 20/20 letter charts currently used by schools, pediatricians and eye doctors. Examination with cycloplegic drops can be necessary to detect this condition in the young.
Since amblyopia usually occurs in one eye only, many parents and children are unaware of the condition. Many children go undiagnosed until they have their eyes examined at the eye doctor’s office at a later age. Comprehensive vision evaluations are highly recommended for infants and pre-school children.