What's the difference between refractive and non-refractive errors?
- refractive errors: Refractive errors occur when the eye does not focus the light that enters the eye, resulting in blurred vision.
- non-refractive errors: Non-refractive errors are caused by eye diseases.
What causes refractive errors?
Refractive errors (myopia and hyperopia, or "farsightedness") have been found to cluster in families. These inherited patterns may be:
- dominant (one gene was inherited from a parent with a refractive error)
- recessive (caused by two genes, one inherited from each parent, who may or may not have a refractive error)
- multifactorial (combination of genes and environment)
Refractive errors are also present in a number of genetic disorders, such as Marfan syndrome and Down syndrome.
What are the symptoms of myopia?
Myopia is usually noted in children around the ages of 9 or 10. It might be discovered if your child cannot read the blackboard from the back of the room, but can see to write and read without a problem.
Other signs and symptoms may include:
- nausea after reading
- holding books close to his face
- writing with his head very close to the table
- sitting very close to the television
- squinting when looking at things that are far away