|
Astigmatism is the most common vision problem resulting in distorted images, as
light rays are prevented from meeting at a common focus.
Astigmatism may accompany Hypermetropia or Myopia
What Causes Astigmatism?
- Normally the cornea is spherical in shape
- But in an astigmatic eye the cornea is shaped more like an oblong Rugby
ball
- The oblong shape causes light rays to focus on two points, rather than
on just one point
- You can see here how the lines on a graph paper appear to a normal eye
and an astigmatic eye
- This can be corrected by using cylindrical lenses
| 
