Astigmatism, which is an irregular curve of the cornea, is so common that more people have it than don't have it. The University of Michigan's Kellogg Eye Center notes that astigmatism is not a disease, but rather a visual disturbance caused by the shape of the cornea. Toric contact lenses correct the visual disturbances caused by astigmatism.
History
Contact lenses were first worn in the late 1800s as heavy glass lenses that covered the entire eye and could only be worn for a few hours. During the 1950s, technology and plastic made the lenses smaller, more practical and with curves to correct for astigmatism. Twenty years later, soft toric lenses that correct astigmatism became available to the public.
Features
Regular contacts are called "spherical" and have one prescription that corrects vision for nearsightedness, called myopia or farsightedness or hyperopia. When a person's cornea has irregular curves on the eye and require more of a prescription, a toric lens has additional power called cylinderbuilt into the contact lens. The extra correction bends light into the retina and helps a person with astigmatism to see clearer.
Types
Today, the two main types of contacts for astigmatism are rigid gas perm or RGP and soft toric lenses. The main difference is the material. RGP lenses are made from a harder plastic and soft contacts are made from soft, gel-like plastic. RGP lenses are smaller and the vision tends to be crisper through this type of lens. Soft lenses are bigger and are weighted to keep the special curves of the lens in a specific place on the eye. When a person blinks, the lenses move slightly and it takes a moment to refocus with a soft lens. Both are comfortable but RGP lenses take longer to get used to wearing.
Misconceptions
Many new styles of toric contact lenses are available. In the past, a person might have been told he cannot wear contacts because they have too much astigmatism or the type of lens they wanted was not available as toric. However, today's toric lenses are made with disposable, tinted and even bifocal contact lens features. A simple contact lens exam with a keratometer, a machine that measures the curves of the eye, helps a doctor decide what type of lens works best for each individual.
Cost and Benefits
Toric lenses cost more than standard lenses. The initial examination and follow-up appointments take more time and most eye doctors charge a larger fee for toric lens fittings. However, the better vision is usually worth the additional cost if a person has enough astigmatism to warrant toric contact lenses.
