Arena Eye Surgeons of Columbus, Ohio Explain: What is a Toric Contact Lens?
Toric contacts are specially designed for individuals with astigmatism. Unlike traditional contacts, which have a spherical shape, toric contact lenses have a geometric surface that resembles a slice from the side of a donut. This unique shape allows the lens to have different refractive powers on both the vertical and horizontal axes.
How Toric Contact Lenses Correct Astigmatism:
Astigmatism is the result of an abnormal curvature of the cornea that causes the refraction of the eye to vary between the horizontal and vertical orientations. These differences in refraction can make it difficult to see fine details, cause blurred vision, and even make vertical lines appear to shift or tilt. Toric contacts compensate for this by allowing different refractive powers on both the horizontal and vertical planes.
Types of Toric Contact Lenses:
Toric lenses come in the same types and wear schedules as standard contacts, including disposable, colored, soft, rigid gas permeable, and hard. Soft lenses may be the most comfortable, but they do have a tendency to shift out of place. Rigid gas permeable lenses are easier to keep in place, but they are more prone to drying out and are more delicate. Some patients also find that it takes them a little longer to adjust to rigid gas permeable lenses than soft lenses. Toric lenses are also available to treat other vision problems in addition to astigmatism.
Special Considerations Regarding Contact Lenses:
Since toric contacts are made with a specific vertical and horizontal orientation, it is important that they are fitted properly and remain in the correct position. Visual clarity is affected if the lens is not correctly situated along the middle axis. Toric contacts are designed with features to help them stay in place, including:
• Truncating or shortening the bottom part of the lens.
• Making a portion of the lens heavier to provide ballasting.
• Thin/thick zones.
Like any other type of contacts, toric lenses do require a prescription from an eye doctor. The optometrist will need to perform a complete eye exam to determine the exact nature of your vision problem and to determine which type of contact is most appropriate based on your eyes and lifestyle.