Five Types of Astigmatism and
What They Do To Your Vision
What is Astigmatism
Astigmatism is noted for being the most common refractive error when it comes to problems with vision and affects nearly two-thirds of the population. Astigmatism is a condition where the cornea is not shaped perfectly spherical. When the Cornea is aspherical in shape as occurs in those with astigmatism, light rays are converged to more than one focal point. Because light rays form multiple focal points this creates unclear vision and can effect vision in both the distance and up close. There are five different types of astigmatism, what are the differences, and how is astigmatism treated?
How Astigmatism Can Be Treated?
The Five Different Types of Astigmatism
With all types of astigmatism light rays come together to form not one but two focal points. The mere fact that there are two focal points formed, instead of just one (in the normal seeing eye) creates vision problems.
The first type of astigmatism is called Simple Myopic Astigmatism, where light comes to two focal points: one before the retina, and one on the retina.
The second type is called Simple Hyperopic Astigmatism, where light comes to two focal points: one on the retina and another focus point that would be a virtual point behind the retina.
The third type is called Compound Myopic Astigmatism where light comes to two focal points, both of which are before the retina but at two different locations before the retina.
As you might have imagined, the fourth type is called Compound Hyperopic Astigmatism where light comes to focal points both of which would be in a virtual location behind the retina but at different virtual locations behind the retina.
Finally, the fifth type is called Mixed Astigmatism where light rays come to two focal points, one of which is before the retina and the other of which is behind the retina