Astigmatism refers to a vision defect wherein the optic of the eye is unable to achieve a sharp, focused image on the retina.
This condition occurs when the refracted light is bent differently once it strikes the cornea and passes through the eyeball. There are two types of astigmatism: corneal and lenticular.
Think of it this way, a normal cornea is shaped like a basketball. This means the roundness of the cornea is even at all points. On the other hand, a faulty cornea tends to curve like a football. Some points of the cornea are steep and others are round. The defect of the cornea causes images to appear blurry or stretched out. This condition is called corneal astigmatism.
On the other hand, lenticular astigmatism occurs when the lens is misshapen.
Signs and Symptoms of Astigmatism
The most common signs and symptoms of astigmatism include blurry vision, distorted vision, eye strain and difficulty seeing at nighttime. Other signs include squinting, frequent headaches, eye irritation, and fatigue.
Causes of Astigmatism
This condition has no known cause. However, most ophthalmologists believe that genetics is a factor in developing astigmatism. There are cases wherein this condition is caused by eye injuries and eye surgery complications. People who are near or farsighted tend to develop astigmatism over time. Apart from genes, people with eye disorders or scarred cornea are likely to develop astigmatism over time. Those who have a history of eye surgery – such as cataract surgery – are also likely to develop this condition as well.
Astigmatism is diagnosed by going through an eye exam. Usually, this condition occurs together with other vision problems such as nearsightedness and farsightedness. Because astigmatism develops very slowly, you need to visit your ophthalmologist regularly to monitor changes in your vision.
Prescription Glasses and Contact Lenses
The most common treatments for astigmatism are prescription glasses and contact lenses. Corrective lenses help rebalance the refracted light into the cornea. However, those with a minor case of astigmatism do not require corrective lenses at all as long as the patients are not nearsighted or farsighted. If astigmatism is moderate to high, corrective glasses or contact lenses are needed.
Rigid Gas Permeable Contact Lenses
For those afflicted with irregular astigmatism, wherein the cornea is misshapen, they will need rigid gas permeable contact lenses or corneal procedures. Before prescribing gas-permeable rigid contact lens, your eye doctor will conduct various tests to determine the ideal prescription.
After performing various tests, your eye doctor will determine the ideal prescription for your astigmatism.
Special soft contact lenses called toric lenses are also prescribed to correct vision problems caused by astigmatism. Toric lenses bend light effectively in one direction, causing a sharper focus of the retina.
A refractive surgery is a long-term treatment for astigmatism. Essentially, the surgeon will shape the cornea into the correct size. This allows the cornea to bend light properly. Do note that there are different types of refractive surgery. The kind of surgery you need will depend on the diagnosis of your eye doctor. To ensure a successful operation, the eyes should be healthy and free from retinal problems, corneal scars, and any eye disease.