What is astigmatism?
Astigmatism is a common eye condition. It can be caused by the presence of a non-uniform shape of the cornea, with the cornea being more curved in particular areas (meridians). The development of abnormalities of the natural lens inside your eye may also cause or contribute to astigmatism.
Normally, the combined refractive properties of the cornea and crystalline lens focus light rays sharply on the retina of your eye. In astigmatism, the lights rays of an object do not come to uniform focus but in two planes, resulting in blurred vision. If short-sightedness (myopia) or long-sightedness (hyperopia) are also present, the planes may be focused in front of or behind the retina.
What symptoms does astigmatism cause?
Blurred vision for distance, intermediate and near
Headache after prolonged activities that require visual attention; this is often caused by partially closing the eyelids, as this tends to improve the vision
Increased difficulty with night vison, as the enlarged pupil at night-time tends to induce ‘night myopia’
How can astigmatism be diagnosed?
Astigmatism and other refractive errors can be diagnosed by your optometrist (optician) or eye doctor. The examination involves a refraction in order to assess the refractive status of the eye.
In the presence of moderate to high levels of astigmatism, a corneal topography scan may be indicated to exclude the presence of keratoconus; this scan maps the shape of the cornea in order to ascertain whether its shape is regular and thus normal. A rapid increase in myopia and astigmatism can also be a sign of keratoconus, a progressive condition in which the cornea becomes weaker and bulges forward; this requires further investigations and treatment.
How can astigmatism be treated?
There are a few options for the treatment of astigmatism:
The vast majority of patients with astigmatism use glasses to see better. With moderate to high prescriptions however, glasses can be difficult to adjust to and may reduce the quality of vision with peripheral distortion.
Specialised soft toric and rigid gas permeable contact lenses can be used to treat astigmatism as the contact lens compensates for the difference in refractive power across the cornea. Contact lenses also correct co-existing long-sightedness or short sightedness at the same time. They are a good option as they overcome the above limitations of glasses. They do have their own limitations though, as they reduce oxygen delivery to the eye. As a result they can cause dry eye and with prolonged use can lead to contact lens intolerance and sight-threatening infection.
A more permanent solution to astigmatism can be provided by refractive surgery. Depending on your prescription, eye measurements and visual needs, a variety of procedures are available, including LASIK, SMILE, toric phakic IOL, e.g. ICL, and refractive lens exchange.
Laser eye surgery provides a permanent treatment to astigmatism by altering the shape and refractive power of the cornea, so that light rays come into focus on the retina of the eye. We offer a range of laser eye procedures, allowing us to recommend the best treatment for your eyes and needs; this includes LASIK, LASEK/Advanced Surface Ablation and PRESBYOND, the laser procedure that can also eliminate the need for reading glasses.
An Implantable Collamer Lens (ICL) is like a permanent plastic contact lens that is implanted in your eye. It is a safe alternative to laser eye surgery, usually chosen for higher prescriptions when laser surgery may not be the best option.
Laser and ICL surgery can dramatically improve your quality of life – if you're interested in finding out more call
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