Myopia, or nearsightedness, is a common vision condition.
Myopia occurs when the cornea's curvature is too steep
or the eyeball is too long, causing light to be focused
in front of the retina, rather than directly on the retina.
Objects are easy to see if they are close, but those in
the distance are blurry.
Hyperopia, or farsightedness,
is also a common vision condition. Hyperopia occurs when
the cornea's curvature is too flat or the eyeball is
too short, causing light to be focused behind the retina,
rather than directly on the retina. Objects are easy to
see if they are far away, but close up objects are blurry.
Astigmatism is a common vision condition that often accompanies
myopia (nearsightedness) or Hyperopia (farsightedness).
Astigmatism occurs when the cornea is shaped irregularly.
Light rays are not focused, but scattered, so that
they focus behind and in front of the retina, rather
than focused on the retina. Vision is blurred at all distances.
Presbyopia is the vision condition that affects people
after about age 40, regardless of those people who have
never experienced eye problems in the past. The lens
of the eye loses flexibility, making it difficult to focus
on close objects.
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