Astigmatism: What is it? How does it affect my eyes?
Astigmatism is a common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision.
Astigmatism occurs when either the front surface of the eye (cornea) or the lens inside the eye has mismatched curves.
Are There Different Types of Astigmatism?
The two main types of astigmatism are corneal and lenticular. Corneal astigmatism happens when there’s a defect or distortion in the cornea. Lenticular astigmatism occurs when there’s a distortion in the crystalline lens within the eye.
Astigmatism is sometimes also described as regular or irregular. Regular astigmatism occurs when the eye isn’t completely curved. So instead of being round like a basketball, it might take the shape of a rugby ball. This often leads to blurry, distorted vision.
An irregular astigmatism, which we often see at Ezekiel Eyes, occurs when the eye isn’t completely round.
Unlike regular astigmatism, where the eye is evenly misshaped, irregular astigmatism has an uneven curvature. This defect also causes distorted vision and blurriness.
At Ezekiel Eyes, we see many patients with irregular astigmatism. Keratoconus, an injury or post-surgery, usually causes this.
What Causes Astigmatism?
It’s not known what causes astigmatism, but genetics is a big factor. It’s often present at birth, but it may develop later in life. It may also occur as a result of an injury to the eye or after eye surgery.
Astigmatism can be associated with patients being nearsighted or farsighted.
A not so rare condition that we see at Ezekiel Eyes is a condition called keratoconus, which does cause astigmatism. This eye disease affects the cornea, causing the clear tissue on the cornea to thin and bulge out. This leads to cloudy or blurry vision and sensitivity to bright lights. The cause of keratoconus is also unknown, but it’s believed to be hereditary and caused by patients excessively rubbing their eyes.
Patients at Ezekiel Eyes have numerous options in the correcting of their astigmatism:
- Spectacles contain a special cylindrical lens prescription that compensates for astigmatism. This provides additional power in specific parts of the lens. Generally, a single-vision lens is prescribed to provide clear vision at all distances. However, patients over age 40 who have presbyopia may need a bifocal or progressive multifocal lens.
- Contact lenses for Astigmatism Some patients will benefit from vastly improved vision with contact lenses rather than spectacles. Contact lenses may provide a clearer vision and a wider field of view. Standard soft lenses may not be effective in correcting astigmatism. Special toric soft contact lenses can correct many types of astigmatism. Rigid gas-permeable contact lenses maintain their regular shape while on the cornea and they can compensate for the cornea’s irregular shape and improve vision for people with astigmatism.
- Orthokeratology (ortho-k) involves the fitting of rigid contact lenses to reshape the cornea. At Ezekiel Eyes we have many patients wearing this type of contact lens modality. Our patients wear their contact lenses overnight and remove them in the morning. Our patients will have clear vision during the day without any visual aids required for most of their daily activities. Orthokeratology does not permanently improve vision. If our patients stop wearing their retainer lenses, their vision will return to their original baseline.
An astigmatism is an abnormality of the regular anatomy of the eye (the shape), and unfortunately there is nothing that can be done to prevent it from occurring.
Want to find out if you have Astigmatism?