Also
known as nearsightedness,
is inherited and is often discovered in childhood.
Myopia often progresses throughout the
teenage years, when the
body is growing rapidly. People with high degrees of
myopia have a higher risk of
detached retina which can be repaired with
surgery.
A myopic, or nearsighted person has difficulty seeing distant objects
clearly, such as road signs, blackboards in a classroom, or scoreboards at
a sporting event.
Myopia varies in its severity. Extremely nearsighted
people may only have clear vision up to a few inches from their eyes;
mildly nearsighted people may not even be aware of the disorder.
Myopia develops during
childhood. The child's eyeball
grows too long,
which interferes with the light-focusing mechanism. Rays of light from
distant objects focus in front of the retina rather than on the retina,
resulting in blurry vision. This can also occur if the cornea is curved
too acutely.
Hyperopia
(close
objects are blurry)
Hyperopia, or farsightedness, is a disorder where distant
objects are usually seen clearly, but close ones do not come
into proper focus and are blurred. This occurs when the
eyeball is too short or the cornea is too flat, and light
rays entering the eye focus behind the retina rather than
directly on it.
Hyperopia is often present at birth, but sometimes,
vision normalizes as the eyeball lengthens during
the growth process. Young adults and children with
mild to moderate cases of farsightedness often see
close objects clearly because the lens is able to
adjust or change its shape.
Because it is often present at birth, there may be a
hereditary risk factor. Age is also a risk factor
for hyperopia.
