Today's contact lenses can correct a wide range of vision problems, making it possible for many people with severe refractive errors to enjoy clearer vision without wearing eyeglasses.
Historically, eyes with high-astigmatism presented a unique challenge in correcting vision with contact lenses. However, thanks to advances in contact lens treatment, it is now possible for those with high-astigmatism to experience clearer vision with contact lenses.
Dr. Walter Choate provides high-astigmatism contact lenses to patients in Nashville, TN. He can help you with your vision correction needs.
Astigmatism is a condition in which the cornea or the lens of the eye are curved differently from each other. In an eye without astigmatism, the cornea and lens are similarly curved, allowing light to sharply focus onto the retina. The difference in curvature between the cornea and lens in astigmatism impacts the way light rays reach the retina, causing light rays to bend improperly.
The way astigmatism causes light rays to bend, called a refractive error, often results in blurry, fuzzy, or double vision.
High-astigmatism simply means the curvature of the cornea or lens is more severe, causing a greater refractive error. With a greater refractive error, vision is generally blurrier or more distorted.
Because astigmatism is characterized by an improperly curved cornea, traditional soft contact lenses are generally insufficient for correcting vision because the flexibility of soft contacts causes them to form to the shape of the eye.
In order to correct astigmatism, including high levels of astigmatism, contact lenses must be able to hold their shape against the curvature of an eye. Thankfully, such contact lenses exist.
These lenses, known as toric lenses, are custom-designed with a unique set of curves to correct refractive errors and improve vision in those with high-astigmatism.
Toric lenses provide effective contact lens treatment for many people with astigmatism. Toric lenses get their name from their torus shape, which is essentially the shape of a donut. This special shape helps toric lenses better focus and bend light to match the needs of those with astigmatism and high-astigmatism.
Toric lenses are soft, gas permeable lenses that utilize different curves and different optical power across the meridian of each lens to uniformly focus light rays to the back of the eyes and create clearer vision.
Additionally, toric lenses are generally made of a breathable silicone hydrogel or a conventional hydrogel, which allows the lenses to remain soft while also maintaining their proper shape.
Toric lenses correct astigmatism through the use of different curves and optical powers. The differing curves and optical powers are distributed across the whole contact lens, providing different correctional power to different parts of the eye. The result is clearer vision for those with astigmatism, even high-level astigmatism.
More specifically, toric lenses use two values, an axis value and cylinder value, to provide customized vision correction. The axis value is determined by the location of the astigmatism on the eye, or the area where the eye is improperly curved. The cylinder value is based on the optical power needed to correct vision. Each value can be adjusted to match each area of eye, thereby correcting blurry vision and other symptoms of astigmatism.
If you have astigmatism and are interested in trading your eyeglasses for contact lenses, toric lenses may be right for you. To find out if you're a candidate, we welcome you to call our staff in Nashville at (615) 851-7575 and schedule a consultation with Dr. Choate.