What Causes Myopia?
Submitted by Dr. Dean Dornic on Sun 11/13/2011 - 11:52
The debate about what causes myopia (nearsightedness) rages on. The fact that myopic parents tend to produce myopic children seems to indicate that myopia has a genetic basis. There is abundant evidence, however, that environment plays a role.
A 1968 investigation by Dr. Frances Young, who led a research team to Alaska to study Eskimo families that were being assimilated into the modern American lifestyle is cited as evidence of the role of reading in the production of myopia. This provided a unique opportunity to test the genetic theory because the parents were illiterate whereas their children were the first generation to go through school. According to the genetic theory, the parents and the children should have almost identical visual systems with little or no myopia.
What Dr. Young discovered stunned the eye care profession. Only 2 out of 130 parents were myopic and the amount of myopia was very small. This was expected because they were living the traditional Eskimo lifestyle of hunting and fishing. In contrast, more than 60% of the children had measurable amounts of myopia! The children obviously didn’t inherit the myopia so Dr. Young concluded that the myopia was caused by long periods of reading as the children went through school.
Another, more recent study, found an association between the use of night lights and the development of myopia. Whatever the environmental influence, the incidence of myopia is clearly increasing in our modern society. Various efforts to prevent or reverse myopia in children such as the use of reading glasses and bifocals have proven ineffective in affecting the course of myopia. Various eye exercise programs have also been a failure.
Thankfully, vision correction procedures such as IntraLase LASIK and implantable contact lenses are becoming safer and more successful allowing millions of patients afflicted with myopia freedom from glasses and contact lenses.