What is induced astigmatism? (Posted: jan 2005)

Induced astigmatism is astigmatism that is present after laser eye surgery but wasn't there before. It could be an increase of existing astigmatism, or new astigmatism along a different axis. This term should not be confused with irregular astigmatism.

What is the difference between induced astigmatism and irregular astigmatism? (posted: jan 2005)

Sometimes these phrases are used in a confusing way. In the context of laser eye surgery complications patients, both kinds of astigmatism are "induced", that is, caused by surgery, but there is a huge difference between "simple" astigmatism, which is a type of refractive error and can normally be fully corrected with glasses or contact lenses, and irregular astigmatism, which is a broader term encompassing curvature irregularities on the surface of the cornea that are NOT correctible with glasses or soft contact lenses.

What causes induced astigmatism? (posted: jan 2005)

If there are no overt complications during or after surgery, induced astigmatism is probably due to a poor quality ablation, that is a laser treatment that for some reason did not deliver the correct amount of energy to the correct places on the cornea. In rare cases this could be because of failure on the surgeon's part to programme in the appropriate amount of correction; in other cases it may be a problem with the fluence or delivery of the laser energy.

Laser eye surgery complications, particularly flap complications or other complications causing scarring, may result in induced astigmatism.

What are the results to the patient? (posted: jan 2005)

Astigmatism is a refractive error and it causes distorted vision. Normally it should be correctible with glasses or soft contact lenses, so the result for the patient (absent other complications) should merely be that s/he must continue to wear glasses or contact lenses.

How is it diagnosed? (posted: Jan 2005)

With a standard refraction examination (the "better 1 or better 2?" variety).

How is it treated? (posted: Jan 2005)

With glasses or contact lenses.

Where can I get more information about induced astigmatism? (posted: Jan 2005)

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