Astigmatism affects about 30% of the population, and is easy for your eye specialist to diagnose. The Optilase team will help you correctly diagnose the problem, and will then explain your options on how to correct it.
The word astigmatism comes from the Greek “a” meaning “without” and “stigma” meaning “spot.”
How Astigmatism affects You
For you to be able to see clearly and sharply, your eye must be able to focus light into a single plane onto the back of the eye at the retina. In people who have astigmatism, a point (or spot) of light is focused instead at two different planes, which then causes blurred vision.
Your eye should have only one focus for all the rays of light entering it. If you have astigmatism, light rays propagate in two perpendicular planes, each of which has different foci.
In an eye without astigmatism, the surface of the cornea is shaped like a Ping-Pong ball, where all the curves are the same. This is called a spherical surface.
In an eye with astigmatism, the surface of the cornea is shaped more like a rugby ball, where there are two different surface curves located 90 degrees apart. This is called a toric surface.
Cause of Astigmatism
Astigmatism doesn’t have any recognised ‘cause’ per se, but it’s an anatomical imperfection in the shape of the cornea, where the front curvature of the cornea is toric, rather than spherical.
Many people have a small amount of odd curve to their cornea; very minor astigmatisms are common. It’s often present at birth or has its onset during childhood or young adulthood. There can be some hereditary basis to most cases, and most people who have it, do so in both eyes.
Importantly, astigmatism is often associated with myopia (near-sightedness) or hyperopia (farsightedness), and can get worse over the years.
Types of Astigmatism
There are different degrees of astigmatism; your Optilase Optometrist will help you determine the details of yours. For example, in usual (‘regular’) astigmatism the meridians in which lie two different curves are located 90 degrees apart; this is fairly common.
In irregular astigmatism, the two meridians may be located at something other than 90 degrees apart, or there are more than two meridians.
If you’ve ever had a bad eye injury or infection and developed a scar in the cornea as a result; or ever suffered from an eye disease called keratoconus; you have astigmatism-probably the irregular kind.
You may be a candidate for Laser Eye Surgery to correct your vision problems; just call Optilase on 1890 301 302 to book a free consultation to find out.
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