What Is Keratoconus?
Refractive errors of the eye -- conditions in which incoming light is refracted incorrectly, causing distorted or blurred vision -- are generally caused by abnormalities in the shape of the eyeball or the curvature of the cornea. Small irregularities in the cornea may cause mild to moderate nearsightedness, farsightedness and astigmatism that can be corrected easily with standard eyeglasses and contact lenses. A condition known as keratoconus, however, requires special handling. Fortunately, modern contact lens options now make it possible for keratoconus patients to enjoy clear vision using these handy products.
Ketatoconus is a progressive thinning of the corneal tissue. Normally the corneal tissue is thick and strong enough to maintain a stable curvature. But in keratoconus, the thinner corneal tissue allows the cornea to bulge outward into a conical shape instead of a semi-spherical shape. This change, of course, affects the eye's ability to refract light. You may experience extreme sensitivity to glare, distorted or blurred vision and/or frequent changes of eyeglass prescriptions as the disorder progresses. If a tiny crack develops in the cornea, you may experience a sudden decline in visual acuity. Over time, scar tissue may form to the extent that a corneal transplant is advisable.
Specialized Contact Lenses for Keratoconus Patients
The good news is that most cases of keratoconus can be treated with corrective lenses that compensate for the abnormal corneal shape. Today's patients actually have several different options to choose from -- and here at Hobson Eye Associates, we're more than happy to provide them. Specialized contact lenses for keratoconus may take the form of:
- Toric soft contact lenses - Milder forms of keratoconus can be corrected with toric soft contact lenses. These special soft lenses are shaped, and sometimes ballasted, so that they'll line up consistently with your corneal abnormalities.
- RGP (rigid gas permeable) contact lenses - RGP contact lenses sit on top of the cornea, providing a smooth, perfectly-shaped surface that permits proper refraction of incoming light in place of the irregularly-shaped cornea.
- "Piggyback" contact lenses - If you want the comfort of soft contact and the superior vision correction of RGP contacts, you can actually wear the rigid lenses on top of the soft lenses. This arrangement is referred to as "piggyback" contacts.
- Scleral contact lenses - Scleral contact lenses are an extra-large form of RGP lens that completely bypass the cornea, sitting instead on the sclera (the white of the eye) beyond the cornea. These lenses move around less than ordinary RGP lenses and put no pressure on the corneal surface, making them a comfortable option.
- Hybrid contact lenses - Hybrid contacts are a refinement of scleral contacts that offer even greater comfort. These RGP lenses are soft around the rim instead of being rigid throughout.
Call Hobson Eye Associates at 770-424-2020 to ask our skilled optometry team about our contact lens options for keratoconus. We can help you make the best choice for your needs!