What is irregular astigmatism? (Posted: jan 2005)

Irregular astigmatism, as used with reference to patients after laser eye surgery, is a bit of a catch-all term used sometimes to describe practically any corneal irregularity that cannot be corrected with glasses and is very difficult to correct surgically. Typically it refers to major differences of refractive power occurring in the central or paracentral part of the cornea, which should all have the same or similar powers after myopic laser eye surgery.

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

Regular astigmatism is an asymmetry occurring along a single axis of the cornea and which can be corrected with glasses or soft contact lenses. Irregular astigmatism refers to more complex irregularities which are bending the light entering the eye in too many directions to be effectively corrected with a spectacle lens.

How can laser eye surgery cause irregular astigmatism? (posted: jan 2005)

There are several possible causes. Any major complication (including flap complications or anything resulting in scarring) can cause irregular astigmatism. However, irregular astigmatism can (and does) still happen without any overt complications simply as a result of a poor quality laser ablation.

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

Irregular astigmatism as a minimum will reduce the patient's vision quality and may reduce the best corrected visual acuity as well.

How is it diagnosed? (posted: jan 2005)

With corneal topography.

What treatments are available? (posted: jan 2005)

Irregular astigmatism is the bane of laser eye surgery - it remains one of the hardest things to correct. The safest and most reliable treatment is gas permeable contact lenses, however, the efficacy of such lenses depends upon many factors including severity and location of the corneal defects and the eye surface health.

Where can I get more information about irregular astigmatism? (posted: jan 2005)

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