One of the most prevalent eye conditions is astigmatism. This condition occurs when the focusing system of the eye does not properly focus light into a single image.
The eye is designed to focus light that enters the eye onto a point in the back of the eye on the retina.
The retina is responsible for transferring information to the brain based on the input into the eyes.
In the front of the eye, two structures are responsible for bending light that enters the eye to allow it to focus on the retina.
The two structures are the cornea and the crystalline lens, which are both designed to focus light on the retina.
Astigmatism affects the eyes and results in blurry vision when the eye focuses to two points instead of a single point on the retina.
Depending on the type of astigmatism, one or both of the points of light may be in front of or behind the retina.
Since the light does not come to a single point, it is spread farther apart and creates a larger, blurrier image to be sent to the brain.
Astigmatism is often developed in childhood or the teenage years, in some unusual cases, it may develop later in life as well.
Most astigmatism is a result of the shape of the cornea, which may not be perfectly round. If the cornea has different amounts of curvature in different areas, it can cause astigmatism.
Other causes of astigmatism include corneal conditions like keratoconus and pterygium.
Keratoconus causes the cornea to change shape and thin in unusual patterns which can lead to irregular astigmatism. This irregular astigmatism may be harder to correct with glasses and require a specialty contact lens instead.
A pterygium is a growth onto the cornea which can cause the cornea to change shape and induce astigmatism. If the astigmatism is caused by a pterygium, there are surgical options to remove the pterygium and relieve the astigmatism.
For most cases of astigmatism, the only needed treatment is glasses or contact lenses. However, if the astigmatism is particularly high or irregular, additional treatment options may include specialty contact lenses, vision therapy, or refractive surgery.
The specialty contact lenses are rigid lenses which are designed to fit over the cornea and rest on the sclera.
These contact lenses can correct irregular astigmatism, like that caused by keratoconus.
If the astigmatism is much higher in one eye than the other, the astigmatism may lead to amblyopia or decreased vision without other causes.
If there is amblyopia, vision therapy can help to build the equality between the two eyes. While the amblyopia may continue to have a reduction in vision, vision therapy can boost the binocular ability of both eyes.