Astigmatism
In this condition factsheet:
Diagnosing Astigmatism
A thorough eye test will include various tests for astigmatism. This is usually done by an optometrist (a doctor who tests vision and prescribes glasses and contact lenses) or an ophthalmologist (a doctor who specializes in eye problems and eye surgery).
Treating and Preventing Astigmatism
There are three ways to treat astigmatism: glasses, contact lenses, and surgery.
Glasses and contact lenses for people with astigmatism have an extra component called a toric lens. This bends light to counterbalance the effects of astigmatism. These lenses are usually a bit more expensive.
Toric contact lenses may be slightly heavier on one side. This side slips to the bottom of the eye, ensuring that the right part of the lens is over the right part of the eye. Some people have found these lenses less comfortable than normal lenses. But contact lens technology is improving all the time, so if you found toric lenses uncomfortable in the past, you might not if you try them now.
Surgery treats astigmatism by reshaping the surface of the eye. For people who are also nearsighted, the surgery can correct both the nearsightedness and astigmatism at the same time.
There are a few basic types of operations, which are usually done in an eye clinic:
- laser-assisted in situ keratomileusis (LASIK)
- laser-assisted subepithelial keratomileusis (LASEK)
- small incision lenticule extraction (SMILE)
- photorefractive keratectomy (PRK or PK)
With LASIK, the doctor makes a small cut into the top layer of the cornea, then folds back this layer like a flap. A laser is then used to mould the inner tissue of the cornea underneath into a better shape. The flap is then replaced.
PRK is done with a computer-guided laser. A computer-controlled laser removes the epithelium (the very top protective layer over the cornea in the front of the eye), then reshapes the cornea by ablating (destroying) tissue in the periphery or outer part. The result is a cornea that is shaped to refract (bend) light correctly.
LASEK is a variation of LASIK and PRK. With LASEK, the flap created in the cornea is thinner, and the laser moulds the outer layer of the cornea (the epithelium).
With SMILE, the doctor uses a laser to sculpt a disc-shaped piece (lenticule) inside the cornea, beneath the surface. Then, a small incision is made in the surface of the cornea, and the lenticule is removed. After the removal, the surface of the eye sinks down, changing the shape and focus of the cornea. This procedure may be an option for those who have mild astigmatism.
Newer refinements of these procedures are constantly under development. One example is "wavefront" or "custom" LASIK, in which a computer maps the visual problems needing correction, increasing the accuracy of the result.
Surgery can only be performed on uninfected healthy eyes. It's not suitable for children and teenagers, whose vision is still changing.
Eye operations don't always produce the desired results. Study results vary, but most people who have laser surgery have improved vision. It is important to realize, however, that some people do not notice any improvement in their vision, and a few end up with poorer vision.
Laser surgery can reduce the quality of your best corrected vision (the absolute best you could see with the right lenses). It can also impair night vision. In addition, the eye can change again after the operation. Sometimes, it heals from surgery into much the same shape it had before, producing only temporary improvement. Because eye doctors like to err on the side of caution, they may under-correct vision, and you may need follow-up procedures. It is important to discuss any potential complications thoroughly with an eye doctor before opting for laser surgery.
If you have mild astigmatism, you might not notice any symptoms. It's important to get regular eye exams to see if you have any eye or vision problems that you may not know about. Having regular eye exams can be especially important for children, as they may be less likely to realize they have issues with their vision.
All material copyright MediResource Inc. 1996 – 2024. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/condition/getcondition/Astigmatism
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