In order to better understand how certain problems can affect your child's vision,
it is important to understand how normal vision happens For children with normal vision,
the following sequence takes place:
Light enters the eye through the cornea. This is the clear, dome-shaped surface that
covers the front of the eye.
From the cornea, the light passes through the pupil. The amount of light passing through
is regulated by the iris. This is the colored part of your eye.
From there, the light then hits the lens. This is the transparent structure inside
the eye that focuses light rays onto the retina.
Next, it passes through the vitreous humor. This is the clear, jelly-like substance
that fills the center of the eye and helps to keep the eye round in shape.
Finally, it reaches the retina, the light-sensitive nerve layer that lines the back
of the eye, where the image is inverted.
The optic nerve carries signals of light, dark, and colors to the area of the brain
(the visual cortex) that assembles the signals into images (our vision).
The following are the most common refractive errors, all of which affect vision and
may need corrective lenses for correction or improvement:
Refractive errors (myopia and hyperopia) have been found to cluster in families. A
variety of inheritance patterns have been observed. These include dominant (one gene
passed from a parent with a refractive error to a child), recessive (caused by two
genes, one inherited from each parent who may or may not have a refractive error),
and multifactorial (combination of genes and environment). Refractive errors are present
in a number of genetic disorders, such as Marfan syndrome and Down syndrome.
Eyeglasses or contact lenses may help to correct or improve hyperopia by adjusting
the focusing power to the retina.