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Description

Astigmatism is a common condition which causes distorted or blurred vision. The cornea is normally round in shape like a football, however with astigmatism; the cornea is oval in shape like a rugby ball. This causes light to be focused incorrectly into the eye, resulting in blurred vision. Astigmatism often occurs along with near-sightedness or far-sightedness. It can be present at birth or it can occur at a later stage.

Symptoms

Astigmatism can cause distortion or blurring of vision at any distance. This can lead an individual to squint in order to see. In some cases it can also cause eyestrain. An individual living with astigmatism may also experience eye discomfort and headaches. In children, astigmatism especially that which differs in degree between the 2 eyes, may lead to the development of amblyopia (“lazy eye”).

Causes

Astigmatism is caused by an irregular shape in the cornea, present either at birth or through issues affecting the cornea later in life. Experts are unsure as to why some individuals are born with astigmatism; however genetics may play a role. Injuries to the cornea at birth or in later life as well as eye surgery may also give rise to this condition. Astigmatism may also be caused by conditions affecting the eye and eyelids. For example, keratoconus, a condition which causes thinning and weakening of the cornea, causes progressive astigmatism.

Diagnosis

As astigmatism can be present from birth, it is important to have regular eye tests from a young age to diagnose this condition. Children with astigmatism are less likely to know that their vision isn’t as good as it should be and are therefore less likely to mention it, so it is important that children have regular eye tests. Uncorrected astigmatism may lead to amblyopia (“lazy eye”) in children.

Astigmatism can be detected using a number of eye tests. A visual acuity test is commonly used to assess the eye’s ability to focus on objects at different distances. This involves reading letters off an eye chart (known as a Snellen chart). The curvature of the cornea may also be measured using a device called a keratometer and may be mapped on a chart using a non-invasive imaging technique called corneal topography. Using this technique, irregularities in the shape of the cornea can be identified and the extent of astigmatism can be determined.

Treatment

There are multiple options available to correct for astigmatism. Your eye care practitioner will advise which option is most suitable for you.

Astigmatism can be corrected with glasses, contact lenses, or refractive surgery (i.e. laser eye surgery), although treatment may not be necessary if the symptoms are mild. Glasses and contact lenses both compensate for the irregular shape of the cornea and help to focus light properly into the back of the eye. Glasses will treat mild astigmatism, while higher astigmatism is better corrected by contact lenses.

Laser eye surgery is another treatment option. This treatment involves using lasers (which are beams of light) to re-shape the cornea so that it becomes more spherical or uniformly curved. This option is suitable for people over 21 years of age, where changes in vision are less likely. There are various types of laser refractive surgery, all of which work on the principle of changing the curvature of the cornea to improve the focus of light on the retina. Laser eye surgery is not safe for everyone and you should consult your ophthalmologist for further information.

Other surgical options to correct astigmatism include artificial lenses that can be inserted into your eye to counteract the blur/distortion/defocus caused by astigmatism.

General eye check-ups are important for people with Astigmatism, as these individuals may still be at risk of developing other acquired eye problems that commonly affect the general population, some of which may be treatable.

No matter what level of vision a person may have, it is important to look after the eyes. To find out more about what can be done to take care of the eyes on a daily basis, please visit our Tips for Good Eye Health.

Research

Astigmatism is actively being investigated by researchers. Many of these research efforts are driven towards optimizing the treatments available.

While much is known about astigmatism, researchers continue to work to understand the condition and why it occurs in some people. One such research study seeks to identify the links between the nervous system and astigmatism.

There is a strong focus on improving the current correction options for Astigmatism and at present, there are many clinical trials which are examining such improvements. These include evaluating new types of contact lens against those currently used for the correction of astigmatism. Intraocular lenses are also being compared with different forms of an intraocular lens used in combination with surgical procedures. These include the analysis of new prediction software to determine the correction required through laser treatment to bring about therapeutic benefit.

Information about clinical trials can be found on their website and can be searched by condition and trial location.

For further information, please contact the research department on 01 6789004 or e-mail research@fightingblindness.ie.

Support

Receiving a diagnosis can be overwhelming for anyone, but this is not a journey that you have to make alone. There are many groups and resources available to provide support for people living with Astigmatism.

Fighting Blindness offers a free and confidential counselling service (Insight Counselling). For further information please contact insight@fightingblindness.ie or call 01 6746496.

A mindfulness group is also available on every Wednesday at the Fighting Blindness office at 11am.

For technology support and guidance, the Dublin-based Technology Exchange Club meets every Monday at the Fighting Blindness office at 11am. Another Technology Exchange Club, based in Cork, meet every Saturday in the Cork City Library, Grand Parade, Cork City at 11am. The Cork-based club do not meet on Bank Holiday weekends or on the second Saturday of the month. For further information please contact insight@fightingblindness.ie or call 01 6746496.

Resources

Féach provides support for parents of children living with sight loss in Ireland.

ChildVision is the national education centre for children with sight loss in Ireland.

NCBI (National Council for the Blind in Ireland) provides support and services for people living with sight loss in Ireland.

Irish Guide Dogs for the blind helps individuals and their families to achieve improved mobility and independence.