Astigmatism is considered a vision condition that is common and results in blurred vision. It tends to occur when the clear front cover of your eye, which is known as the cornea, is shaped irregularly or due to the lens’ curvature within the eye. 

If the cornea or lens is irregularly shaped, it can keep light from properly focusing on the retina, which is the light sensitive surface located at the back of your eye. Because of this, you have blurred vision, leading to discomfort as well as headaches. 

Astigmatism often occurs with various other eye conditions like nearsightedness (myopia) and farsightedness (hyperopia). These eye conditions are known as refractive errors together since they impact how the eyes refract or bend light.

There are numerous causes for astigmatism. In some cases, it may be hereditary and present at birth. Over time, it may increase or decrease.

A comprehensive eye exam will include various testing for this condition. If needed, your eye doctor will provide eyewear that can correct astigmatism by changing the way that light enters your eyes.

Another way that astigmatism can be treated is orthokeratology, which is a corneal procedure and often referred to as ortho-k. It is a painless and non-invasive procedure in which the patient will wear a series of rigid content lenses that are specially designed to reshape the cornea’s curvature over time. 

Laser surgery is another option of treatment in some cases. The laser will alter the cornea’s shape by removing a small portion of the eye tissue.

What Is the Cause of Astigmatism?

The curvature of the lens and cornea bends the light that enters into the eye in an effort to focus it on the retina. With astigmatism, the surface of the lens or cornea has a different curvature.

The surface is shaped similar to that of a football as opposed to a basketball, and because of this, the eye can’t focus light to a single point. As a result, vision is out of focus.

Also, the curvature of the lens within the eye may change, causing a decrease or increase in astigmatism. This alteration may occur during adulthood and occur before the development of cataracts. 

In some cases, astigmatism may occur after eye injury or surgery.

Astigmatism may occur as a result of keratoconus, which is a relatively rare eye condition where the cornea becomes cone-shaped and thinner. This can result in a significant amount of astigmatism, and it causes inadequate vision that can’t be properly corrected with prescription eyewear. Individuals with this condition generally need contacts for clear vision and may even eventually require a corneal transplant.

How Can Astigmatism Be Diagnosed?

An eye doctor can work to properly diagnose the condition with a comprehensive eye exam. Testing for the condition measures the way that the eyes focus light and also determines the power of optical lenses that are necessary to improve the vision. The exam might include the following:

  • Visual Acuity – When you are reading letters on a chart, this is known as measuring for your visual acuity. Your visual acuity is a fraction, such as 20/40. The top number is the distance for the standardized testing, such as 20 feet, and then the bottom number is the smallest letter that you were able to successfully read. Therefore, an individual with 20/40 visual acuity would need to be within 20 feet in order to read a letter that can normally be seen with clear vision at 40 feet. Normal visual acuity is 20/20.
  • Topography/Keratometry – A corneal topographer, which is gaining in popularity, will generate a contour map of your cornea and offer incredible detail of the shape of the cornea. However, a keratometer is more commonly used to measure the cornea curvature. By primarily focusing a circle of light on your cornea and measuring the reflection, it’s completely possible to determine the precise curvature of that section of the surface of the cornea. This particular measurement is vital in determining the adequate fit for contacts.
  • Refraction – With a phoropter, your eye doctor will place a series of lenses in front of the eyes and measure the way they focus light rays. This takes place with the use of a lighted handheld instructed known as a retinoscope. Alternatively, an automated instrument can be used that will evaluated the estimated focusing power of your eye. Based on the results, the power will be refined to determine the lenses that will permit the clearest possible vision. Despite the enhanced technology, your input continues to be integral to determining your vision needs.

With the data from the aforementioned tests, your eye doctor will be able to determine whether you have astigmatism. He or she will utilize this information, combined with the data from any other tests conducted, to determine the power of any potential lens correction that may be needed to offer clear and comfortable vision. As soon as testing has been completed, your eye doctor will discuss potential options for treatment.

How Can Astigmatism Be Treated?

Individuals with astigmatism have multiple options at their disposal to regain clear and comfortable vision. Some of these include the following:

  • Eyeglasses – Individuals with this eye condition will generally choose eyeglasses to gain vision improvement. Eyeglasses consist of a special prescription cylindrical lens that helps to compensate for the condition. This can offer supplemental power in certain parts of the eye lens. As a general rule, a single vision lens can be prescribed to offer clear vision at any distance. However, individuals over the age of 40 with presbyopia may require a progressive addition or bifocal lens.
  • Contact Lenses – Some individuals may gain enhanced vision with contacts as opposed to eyeglasses. Contacts may offer better vision as well as a wider field of view. However, due to the fact that contacts are worn right on the eyes, they do require routine care and cleaning to ensure eye health. Standard soft contacts may not necessarily be effective in correcting the condition. However, special toric lenses can be effective at correcting many forms of astigmatism. Due to the fact that rigid gas-permeable contacts keep their normal shape while they are on the cornea, they are able to compensate for the irregular shape of the cornea and improve vision for individuals with astigmatism.
  • Orthokeratology – Ortho-k consists of a series of rigid contacts in an effort to reshape your cornea. Individuals wear these contacts for a limited period of time like overnight and then will remove them. Individuals who have moderate astigmatism might obtain temporary clear vision without these lenses for many of their day-to-day activities. Ortho-k doesn’t improve vision permanently. If individuals stop wearing the lenses, vision could return to its normal state. 
  • Laser/Refractive Surgical Procedures - Astigmatism may be able to be corrective by using LASIK or PRK to reshape the cornea. LASIK is a surgical procedure that removes the tissue from the inside layer of the cornea, while PRK is a surgical procedure that removes tissue from the inside layer as well as the superficial layer of the cornea. 

If you have been told you have an astigmatism, there are many options for treatment. If you would like to learn more, get in touch with us at Performance Vision Inc.