What is Astigmatism?
In simple terms astigmatism means that the eye or in most cases the cornea is shaped more like a football than a basketball. This results in the light entering the eye being focused in an irregular way or the light is not focused to a single point on the retina.
What Causes Astigmatism?
In most cases the person is born with a cornea that is shaped like a football. As one ages the astigmatism may become worse. In some cases the astigmatism may be due to an irregular shaped lens inside the eye.
Types of Astigmatism
This means that the axis of the misshaped cornea is located 90 degrees apart from each other.
This exists when the axis of the astigmatism is not symmetrical and lies in an axis not 90 degrees apart. This type of astigmatism is more problematic to correct or treat. This can be caused by injury, other corneal scarring, and keratoconus (a corneal disease in which a portion of the cornea thins and bulges forward in an irregular way).
Symptoms of Astigmatism
Astigmatism blurs the vision if there is enough present both at distance and near. It can be associated with myopia (nearsightedness), hyperopia (farsightedness), or just by its self.
Streaks coming from lights at night are a common complaint of astigmatism.
Eye strain or headaches may be due to astigmatism.
Diagnosis of Astigmatism
A routine eye exam with a refraction will find the astigmatism. In some cases especially with irregular astigmatism a corneal topography test may be performed. This equipment measures the shaped of the cornea and looks like a 3D geographical map showing the mountains elevated up.
Treatment or Correction of Astigmatism
In most cases glasses can be prescribed to correct the astigmatism.
Hard or gas permeable contact lenses give great vision and some cases of irregular astigmatism may be the only way to correct the vision. Toric soft contact lenses can also correct astigmatism.
Surgery for Astigmatism
Depending on the severity and type of astigmatism, there are techniques to correct astigmatism. These include limbal relaxing incisions or astigmatic keratotomy, LASIK, and Conductive Keratoplasty.