What is Astigmatism?

What are the symptoms?

This eye problem usually symptomizes as blurred vision at all distances. When an astigmatism is left untreated, an individual will often experience eye strain, headaches and squinting, particularly after lengthy visual tasks such as working in front of the computer, reading or driving.

What Causes an Astigmatism?

Astigmatism occurs due to an abnormally shaped cornea. Most corneas are even and round, but with astigmatism, it is shaped more like a football. Less commonly, it can be caused by the shape of the lens. Astigmatism can be genetic, usually present from birth. In fact, most astigmatisms occur early in life, which is why is so important to schedule your child for an eye exam well before they start school. This will avoid any learning issues resulting from poor vision. Astigmatism can worsen over time from lack of treatment, mistreatment, and after certain treatments such as glaucoma surgery, or even get better with correct treatment.

What are the Types of Astigmatism?

Optometrists will classify astigmatism as either regular or irregular during your eye exam:

• Regular Astigmatism: the principal meridians are 90 degrees apart. Most astigmatisms fit into this category, with regular corneal astigmatisms.
• Irregular Astigmatism: the principal meridians are not perpendicular. These types of astigmatisms can be caused by an eye injury which has resulted in scarring on the cornea. This can happen after certain eye surgery or from keratoconus, a disease that causes corneal thinning.

How is an Astigmatism Detected?

Astigmatism can be detected during an eye exam with the same devices and methods used for checking for near- and far-sightedness. Your optometrist will perform a retinoscopy – shining a light into your eye while manually introducing a series of lenses between the light and your eye. There are now also computerised instruments that provide faster tests for astigmatism. Vu has the equipment to perform various eye imaging tests during your eye exam with our advanced optometry technology. After these initial tests, your eye doctor will perform another test known as a manual refraction to refine the results. During this test, the optometrist will use a Phoropter to test out various lenses in front of your eyes.

How is it Corrected?

Astigmatism can typically be corrected with eyeglasses, contact lenses, or surgery. A prescription for astigmatism will also include an extra ‘cylinder’ lens power to correct the difference between the powers of the two principle meridians. Lasik can correct most types of astigmatism; however, this usually requires your prescription to remain the same for an extended period of time and will require monitoring and planning with your eye doctor.

The best option for correction of astigmatism can be discussed with your optometrist. They will know the best outcome for your particular case as every individual is different. If you are having trouble seeing clearly, book an appointment with our experienced optic team.