What is Astigmatism?
Despite being a relatively common problem, many people know little or nothing about astigmatism - so much so that you may have astigmatism without even realising it. In this article we’re going to explain what astigmatism is and the causes behind it, as well as the means of correcting astigmatism.
What is astigmatism?
Astigmatism is a common eye condition. Although it causes blurry or distorted vision, it is usually a minor condition. It affects a large portion of glasses wearers, and people with astigmatism are likely to suffer from short or long-sightedness.
If astigmatism goes untreated, it can also lead to symptoms such as eye strain, headaches and fatigue. These are particularly exacerbated after carrying out tasks that require intense or extended focus, such as reading.
Why does it develop?
Astigmatism is essentially a refractive error, meaning that it is a problem with how your eye focuses the light coming in towards it. This is typically a result of the cornea – the transparent layer of tissue covering the front of your eye - not being the perfectly curved shape necessary for the eye to focus correctly.
Rather than being perfectly spherical, the cornea in the eye of an astigmatism sufferer would have a slightly more oval-like shape. Consequently, when light hits the cornea, it will come into multiple focus points around the retina, as opposed to the single focus on the retina required for clear, sharp vision. Therefore, vision can appear blurry.
In rarer cases, astigmatism can be caused by the lens inside the eye. This particular form of the condition is known as lenticular astigmatism. It occurs when an irregular-shaped lens bends light unevenly within the eye.
It is believed that some cases of astigmatism may have a hereditary element, although there is little clarity as to why some people are born with it. There are various other possible causes, which include:
- Changes made to the cornea as a result of eye surgery
- Eye conditions that cause the cornea to bulge, get thinner and change shape such as keratoconus and keratoglobus
- Infections that may scar the cornea
- Injuries that damage the surface of the eye
When does it develop?
The majority of people who have astigmatism are born with it, and it is important to ensure that your children have their eyes tested regularly. However, astigmatism can happen at any age. Therefore, it is essential to ensure that you pay regular visits to your optician.
Who gets astigmatism?
Astigmatism is found in people who wear glasses. A calculation based on 11,624 spectacle prescriptions reveals that 47.4% and 31.8% were the prevalence of patients showing astigmatism of 0.75 and 1.00 D or greater in at least one eye, while the figures for both eyes are 24.1% and 15.0% respectively.1
Can astigmatism be corrected or cured?
In many cases, corrective treatment isn’t necessary as the symptoms of astigmatism are usually very mild. However, should you require treatment, you generally have two options:
- Corrective lenses
The use of corrective lenses is the less extreme of the two options. Here, the lenses will compensate for the irregular curve of the cornea. Glasses and contact lenses are usually equally effective at treating astigmatism. The type of corrective lenses you decide to use will therefore depend on your personal preference and the advice of your optometrist.
However, if you choose to use corrective contact lenses, it is important that you closely follow the instructions for usage, including how long to keep them in and washing and sterilising them correctly. Otherwise, your eyes can run the risk of suffering from bacterial infections or other eye conditions such as dry eye.
- Laser eye surgery
For those who do not want to bother about using contact lenses or glasses, laser eye surgery may be an option. This would entail the use of lasers to remould the corneal tissue to give it the correct curvature required to refract light onto the retina correctly.
Those considering laser eye surgery will likely have to pay for it themselves. The NHS doesn’t consider it an essential form of treatment.
Does astigmatism have long-term effects?
Astigmatism only really poses the risk of long-term effects if it goes undiagnosed for several years, particularly in children. It can result in insufficient development of the eye, a condition otherwise known as ‘lazy eye’. With the correct diagnosis and treatment, there is usually no reason why astigmatism should lead to any long-term effects.
While astigmatism usually occurs as a result of an irregular cornea, there are multiple other irritants which can also damage the surface of the eye. These include artificial light, pollution and lack of sleep, all of which are contributing factors to a common condition known as “urban eye”. To find out more about other eye conditions, including urban eye, and to explore the various solutions in the Optrex range of eye care products, please click this link.