The term astigmatism is used to describe a cornea that isn't
round. Instead, it's shaped like a football rather
than a round, spherical basketball. Like a football,
the astigmatic cornea has two curves: a steeper one,
and a flatter one 90 degrees away. These two curves
bend light entering the eye, causing two images to form on
Patients with astigmatism may notice blurred or ghost images close up or far away. Astigmatism may be present in various degrees and is found in approximately 30 to 40% of individuals who wear glasses or contact lenses
If you have an astigmatism - blurred or distorted vision caused by an oblong-shaped cornea - and need cataract surgery there is now an option to remove your cataract and treat your astigmatism at the same time!
For significant amounts of astigmatism a Toric implant or lens with the astigmatism correction ground into it and orientated precisely is recommended.
The Toric intraocular lens (IOL) has a unique design that offsets the imbalance of the corneal astigmatism. This will allow you to see better at distance, or near, without glasses than with a traditional monofocal IOL. The Toric lens is a foldable, single-piece lens that is made of the same biocompatible lens material that has been successfully implanted since 1991.
This lens has a uniquely designed surface that helps reduce or eliminate the astigmatism in your eye. The actual procedure to implant the Toric lens is similar to traditional small-incision cataract surgery. As with all technological breakthroughs, the Toric lens will work better for some patients than others. As always, a comprehensive pre-surgical evaluation is necessary before determining which lens implant will be right for you.
For minor degrees of astigmatism Limbal Relaxing Incisions are adequate .
Limbal relaxing incisions (LRI) are truly a modification of astigmatic keratotomy (AK), which is a procedure to treat astigmatism is present when the cornea is not spherical, i.e., it is steeper in one meridian than the opposite meridian 180 degrees away. The cornea with astigmatism may be thought of as being more football shaped rather than basketball shaped.
LRI’s are incisions that are placed on the far peripheral aspect of the cornea (the limbus) resulting in a cornea that is more round. The astigmatism is thus reduced and uncorrected vision is improved. The procedure can be completed in a few seconds after numbing the eye with anesthetic drops. There is usually little if any post-operative discomfort. The procedure is extraordinarily safe and is not associated with glare or starburst, as often occurs with true corneal incisions (RK and AK).
Furthermore, the cornea is usually stable within a week, indicating that visual fluctuations have typically resolved by that time interval. Limbal relaxing incisions have gained widespread acceptance amongst cataract surgeons where it is often combined with the cataract operation to reduce pre-existing astigmatism. This results in better post-operative vision without glasses. The procedure can also be used in individuals whose primary refractive error is astigmatism.