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Astigmatism A refractive error caused by an irregular shape of the cornea (much like a football). Astigmatism is measured in terms of diopters, cylinder meridian or axis. Uncorrected astigmatism may produce ghosting or double images. Does my degree of astigmatism matter? Nearsightedness, farsightedness and astigmatism can all be successfully treated today with LASIK - up to certain approved parameters, depending upon the laser and the skill of the surgeon performing the procedure. For example, people who wear glasses only for reading are not good candidates. In addition to the visual and medical requirements, up to 14 diopters of myopia, or nearsightedness, with up to 5 diopters of astigmatism for the VISX STAR S2 Excimer Laser System. The best candidates tend to be people who are dissatisfied with their contact lenses or glasses and are motivated to make a change, whether it's due to occupational or lifestyle reasons. However, only an eye doctor who is specially trained can evaluate whether or not a patient is medically suitable for laser vision correction. Does age matter? Laser eye surgery used to be for those under 40, this is not true anymore. More and more patients over 40, 50 and even some over 60 have had successful laser eye surgery. Patients need to be at least 18 years of age or older for the treatment of mild nearsightedness. Patients under 18 may not have finished developing and may need to wait until they are at least 18 years old. If you have a higher degree of nearsightedness or astigmatism you should probably wait until you are 21. This is something you will need to discuss with your ophthalmologist. What are my choices? Patients who were formerly considered poor candidates for refractive surgery are increasingly becoming eligible for surgical correction because a combination of complementary procedures can now be employed. Refractive combinations make sense when the two procedures address different refractive problems, different aspects of the total problem, when the problems exceed the approved scope of the individual procedure, or when the first procedure has altered the eye in such a way as to narrow down options for further enhancement. The decision as to which technique or combination of techniques is best for any individual should be determined based on the exact nature of the vision problem during the consultation with an ophthalmic cornea specialist. This specialist can help determine what is best for the patient based on his/her lifestyle and other factors. Astigmatic(AK) Keratotomy AK is a variation of RK used to treat astigmatism. AK involves arc-shaped incisions in the cornea, whereas RK involves radial incisions (like the spokes of a wheel). AK is often performed in conjunction with RK. The side effects from AK are mild and healing is generally quick and easy. AK will diminish or eliminate astigmatism. Astigmatic Keratotomy is often performed in combination with other refractive procedures. LASIK The LASIK procedure corrects mild to severe levels of nearsightedness (myopia), farsightedness (hyperopia), or astigmatism. Limbal Relaxing Incision(LRI)LRI is a procedure used to correct mild (-1.00 to 2.00 diopters) astigmatism. LRI is a modification of radial keratotomy and are often performed with RK or cataract surgery. To treat astigmatism, the cornea must be made more spherical or uniformly curved. Rather than flattening the entire cornea as with RK, LRIs are placed at the very edge of the cornea (the limbus) at the steepest curves. This causes the cornea to relax and become more round. Symptoms of Astigmatism Include:
Degrees of Astigmatism
Most
people have some degree of astigmatism. Astigmatism occurs when the
front surface of your eye (cornea) is slightly irregular in shape,
resulting in vision being blurred at all distances. Astigmatism is
not a disease, but is actually a vision condition that is quite common.
When the front of your eye is more oval than round, light does not
focus properly on the back of your eye (retina). The causes of this
irregular shape are unclear. In some cases, it may be hereditary or
it may result from such factors as pressure of the eyelids on the
cornea, incorrect posture or an increased use of the eyes for close
work.
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