What is Astigmatism?
Astigmatism is an optical error correctable with glasses, contact lenses, or surgery. The cornea (the window to the eyeball) accounts for most of the astigmatism of the eye. Instead of being round like a basketball, the cornea is shaped like an egg. This is just another optical error. Astigmatism may be low, moderate or high in amount. Astigmatic corrections are incorporated into your eye glass prescription. Patients with astigmatism may be near-sighted, farsighted, or presbyopic.
Can Contact Lenses Correct for Astigmatism?
Yes. Special soft lenses, designed to correct for astigmatism, are called Toric lenses. These lenses have an astigmatic correction fabricated into the lens. For them to work properly, the lens must move up and down without twisting upon blinking. Rotation of the lens with blinking results in unstable vision. Another way of correcting for astigmatism with contact lenses is to use a firm or gas permeable lens which neutralizes the astigmatism of the cornea.
Can LASIK Correct Astigmatism?
Yes. It does an excellent job. Dr. Spencer can utilize a Custom Wavefront guided LASIK treatment to deliver vision even better than glasses or contacts!
Can Cataract Surgery Correct Astigmatism?
Yes Traditional cataract surgery corrects only the non-astigmatic component of the refractive error. Specialized TORIC Intraocular Lenses (IOL’s) can be implanted by Dr. Spencer at the time of surgery to correct astigmatism. For milder astigmatism a procedure called Astigmatic keratotomy (AK) can either eliminate or significantly reduce corneal astigmatism. Small incisions are made in the periphery of the cornea to relax the cornea and decrease the astigmatic errors.
What is Irregular Astigmatism or Keratoconus?
The shape of the cornea is distorted, thus, the Irregular Astigmatism is unpredictable. Keratoconus is a type of irregular astigmatism in which the cornea is unstable because it has unusually thin areas. This causes it to bulge or distort, causing vision to blur. Glasses can not be fabricated to correct for this optical error or distortion. Firm or rigid contact lenses must be used to smooth the surface of the irregular astigmatism. If a patient has Keratoconus and contact lenses provide adequate vision, then no other treatment should be contemplated. However, if the patient can not tolerate a contact lens or can not see well out of his/her contact lenses, either intra-stromal rings or a corneal transplant to replace the old cornea should be performed. The procedure is usually successful (90%). Keratoconus because of its irregular astigmatism and associated corneal thinness is a contra-indication for LASIK (refractive surgery). A new non-surgical treatment called Corneal Cross-Linking has shown success in stabilizing and even reversing some mild to moderate keratoconus. Riboflavin (vitamin B2) drops are placed in the eye during corneal collagen cross-linking treatment and a special UV light is used to modulate the corneal collagen and strengthen the fibers to reduce the astigmatic bulging.