Your yearly visit to your optometrist should be a routine thing. Read a few letters, get your eyes dilated, and walk out wearing those really silly looking paper sunglasses, and you’re set for another 12 months. This year, though, something changes. Your optometrist says that you’ve developed an astigmatism and hands you a new prescription as he shoos you out of his office. What is an astigmatism? Is it something that you need to worry about? We’ve collected some basic information here to help set your mind at ease.
What is Astigmatism?
An astigmatism is caused by an imperfection in the cornea. In a normal eye, the cornea (the front surface of the eye) is curved evenly on both sides. When one side is curved slightly more or less than the other, this causes an astigmatism.
There are two primary types of astigmatism:
- Corneal astigmatism: When the cornea is irregular in shape
- Lenticular astigmatism: When lens of the eye is irregular in shape
How common is an astigmatism?
This is actually one of the most common diagnosis, affecting as many as 1 in 3 individuals. There are varying degrees though, and many people with minor astigmatisms don’t require the use of any sort of corrective lenses.
What are the symptoms?
When most people go to the eye doctor, it is because they are having trouble seeing things either close to their eyes, or far away. With an astigmatism, the blurred vision often occurs at all distances. It is also usually accompanied by eye strain and moderate to severe headaches.
Why does an astigmatism develop?
There is no exact answer to this question. They can be present from birth, or develop later in life. There are some studies that suggest it could be genetic, but there are no conclusive answers as of yet.
However, statistics also show that premature babies and people born with a low birth weight have a higher percentage of developing astigmatism due their cornea not curving properly from birth.
How is astigmatism diagnosed?
There are multiple tests that your ophthalmologist might perform to determine whether or not you have astigmatism. These include:
- Vision tests: Everyone is familiar with these. You read a chart of letters (or symbols for young children) from across the room.
- Keratometer: This device is designed to measure light reflection from the cornea. This allows the doctor to determine the curvature of the cornea and definitively see whether or not astigmatism is present.
- Light Focus: A couple of different devices are used to test your eye’s ability to focus light. A phoropter is used to place different lenses in front of your eyes. You’ll often be asked to read the same chart that is used in the vision tests while the doctor changes the lenses to make it easier for you to see. A retinoscope uses a direct beam of light to allow the doctor to see how your eyes focus when exposed to light.
How are astigmatisms treated?
In most cases, the use of prescription lenses is the only treatment that is need for astigmatisms. Eyeglasses and contact lenses can both be used for this purpose. There is also a type of rigid contact lens designed to correct astigmatism by gently pushing the cornea back into its correct shape.
Eye surgery, such as LASIK is also an option for astigmatism treatment. This can be a great idea if you also suffer from near or far-sightedness and want to kill two metaphorical birds with one stone.
Nothing to worry about
If your doctor hands you an astigmatism diagnosis and a prescription, don’t worry! Not only is it one of the most common diagnoses, it is easy and painless to treat.