What is astigmatism and how to correct it?

What is astigmatism? 

 Astigmatism is a refractive error that is quite common for both children and adults. It is a condition in which the eye fails to focus light onto the retina evenly. Astigmatism arises when the light that strikes the cornea is bent differently. It is because the shape of the cornea or crystalline lens is irregular as opposed to the typical spherical shape.  Simply, the eye is not perfectly spherical. Astigmatism correction is done using special spectacle lenses or contact lenses.

A comprehensive eye exam by an optometrist is undertaken by patients who might suspect astigmatism.  The optometrist will provide glasses or contact lenses prescription if necessary at the conclusion of the eye exam. 

Astigmatism results in a blurred or distorted vision to some degree. Common symptoms associated with astigmatism include headaches, eyestrains, and squinting. Some patients having slight astigmatism will fail to notice the change in their vision. It is therefore essential to have regular eye examinations to determine astigmatism.


How to correct astigmatism? 

Spectacle lenses (Glasses)

The use of glasses is the most common method used to correct vision. Eyeglasses having cylindrical lenses are the most popular way of correcting astigmatism.  Studies have shown that most patients with high astigmatism prefer glasses. Glasses are either positive or negative depending on the type of prescription. These glasses have special cylindrical lenses, which compensate for astigmatism by providing additional powers in certain areas of the lens. In most cases, a single-vision lens is provided which serves to provide clear vision. Nonetheless, patients who are over 40 years and have presbyopia may be prescribed an additional progressive or bifocal lens.

Contact lenses

Contact lenses are also another way of correcting astigmatism. Some years back, astigmatic patients could not use soft contact lenses; instead, the correction was only possible by the use of hard contact lenses, an example being the gas permeable contact lenses. Today, astigmatism correction is carried out using unique toric soft contact lenses. These contact lenses can have toric on either the back or the front surface. The contact lenses having toric on the front surface will correct both lenticular and corneal astigmatism of up to 4.5 D. Corneal astigmatisms is corrected by contact lenses having a toric back surface. Usually correction is up to 60. D with the custom designs. 

The use of custom contact lenses is known to remedy high astigmatism as well as allowing favorable conditions for binocular vision. Many patients also prefer contact lenses over glasses for cosmetic reasons. 

Since these contact lenses are worn directly to a patient’s eye, they should ensure that they are regularly cleaned and cared for to protect their eye health.

Laser vision correction 

For the right candidates, procedures such as LASIK, LASEK, or PRK can also correct astigmatism. 

Patients with astigmatism have a broad range of options to correct their vision condition. Upon consultations with the optometrist, patients can select the treatment that best fits their visual needs and life style. To book your eye exam and consultation with one of our optometrists call our downtown Toronto today.