Astigmatism is an eye ailment that affects the way in which light enters our eye. When light passes through an eye with astigmatism, the light does not come to a single focus point inside the eye. Instead, the light comes together at two focal points; thus making it hard to see fine details.
Main Symptoms
The leading symptom that occurs with astigmatism is blurred or distorted vision. Often this will be difficult to diagnose by yourself. This is because the primary symptoms can be like those encountered with Myopia (nearsightedness). So, it might be hard to differentiate. What makes astigmatism different is: the challenges the eye has in seeing small detail. This can be for objects close or distant.
A few additional symptoms experienced by those with astigmatism include: excessive squinting and sensitivity to light, constant eye strain, and constant headaches.
Causes
Typically, there are two main causes for Astigmatism:
The first is Corneal Astigmatism. The reason that leads to this type of astigmatism is a result of an irregular shaped cornea. The cornea is the front outer portion of the eye. This clear membrane is there to help protect the eye and is responsible for aiming the light inwards. A regular shaped cornea has a round shape to it, such as the shape of a basketball. This cornea will transmit just one image onto the retina. The retina is located at the back of the eye.
When we have an irregular shaped cornea, the cornea instead will have a somewhat elongated shape, comparable to an oval shape. This affects the manner in which light travels through the eye. It prevents the light from projecting a single image. Instead, it projects an image in two spots; which makes it difficult for one's eye to focus in on small details.
The second cause is Lenticular Astigmatism. In this case, the astigmatism is a result of an irregular shaped lens. This portion of the eye is not at the outer surface, but instead situated inside the eye. It is located right behind the iris. Just as in the case of corneal astigmatism, the irregular shape, or wrong position, of the lens can also cause images to be incorrectly projected on to the retina.
Ways to Diagnose
To determine if you are suffering from astigmatism, a health specialist may employ one or a combination of the following eye tests:
- The Visual Acuity test. This test is the most common and familiar eye test, where you will be asked to read letters that become progressively smaller, from a chart placed some distance away from you.
- Astigmatic Dial. With this test, you may be asked to describe a series of lines in a semi circle on what is called an Astigmatic Dial. If you have astigmatism, some lines will appear clearer than others.
- A Keratometer or Ophthalmometer device. This is a device that measures the amount of reflected light from the surface of the cornea. These measurements are used to determine the radius of curvature of the cornea.
Correcting
Astigmatism is considered a minor health condition, and eye specialists usually prescribe corrective lenses to compensate for the astigmatism. However, there are also other alternatives. The following are 4 options to help with astigmatism:
- Corrective lenses
- Orthokeratology (a program that uses a special rigid contact lens)
- Laser surgery
- Eye exercises
It's good to learn more about these options, in order to make a better decision on which you might prefer. The important thing to note is that there are ways to correct for astigmatism.
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