WHAT IS KERATOCONUS?
Keratoconus is a condition where the cornea, the clear front surface of the eye, starts to thin and bulge forward. For this reason, patients have difficulty seeing clearly, even with glasses. Symptoms may include blurred vision, starbursts, double vision, light sensitivity, and frequent squinting.
There isn't a definitive cause of keratoconus but it is thought to be linked to genetics, vigorous eye rubbing, and/or allergic conditions. The condition usually manifests in puberty and can progress until 40 years of age, although every patient is very different and progression can stop before or progress after 40.
Keratoconus usually affects both eyes but one eye may have a much more advanced form of keratoconus than the other eye. Every patient with keratoconus has a different presentation. Some may stay with a sub-clinical, or mild, condition, while others develop an advanced form very quickly.
WHY CAN'T PATIENTS WITH KERATOCONUS SEE WELL WITH GLASSES?
An image results from rays of light going through the eye. With keratoconus, once light rays go through the glasses, they still hit an irregular cornea and the light bends and cannot reach the retina in a straight line.
Rigid contact lenses are the best way to obtain clear vision with keratoconus. The reason for this is because tears fill the area between the abnormal cornea and the spherical contact lens, essentially creating a "new" corneal surface where light rays can travel to the retina as straight as possible, creating a clear image.
Soft contact lenses generally do not work as well as rigid contact lenses because the soft lens drapes around the irregular corneal shape and provide the same vision as with glasses.
WHAT ARE TREATMENTS FOR KERATOCONUS?
Currently there are no true treatments for keratoconus, but there are management strategies and surgical procedures that can halt progression and improve vision. The best thing you can do is team up with a eye care professional who is well versed in keratoconus and the disease process. They can point you towards whether a surgical procedure can be beneficial. The earlier the diagnosis, the better the prognosis.
Because our office specializes in contact lenses for keratoconus, our goal is to manage your condition, stop progression, (referring to one of our excellent ophthalmologists if surgical intervention is indicated) and to fit the highest quality contact lenses possible to maintain health of the eye, optimize vision, and avoid a corneal transplant.
WHAT CONTACT LENS OPTIONS ARE THERE FOR KERATOCONUS?
Contact lenses are a great option for those with keratoconus because the tear film between your cornea and the lens can mask a lot of the condition and create a "new" corneal surface with the lens that helps you see more clearly.
1.) Scleral Lenses
Scleral lenses are large gas-permeable (rigid) lenses that are able to vault over even the largest of corneas with keratoconus. These lenses are filled with a sterile saline solution each morning before insertion and the saline stays on your eyes all day. The lenses rest on the white portion of the eye (the sclera) instead of on the cornea so there is not the risk of corneal scarring from a poor-fitting lens. They are very comfortable.
2.) Rigid Gas Permeable Lenses (RGP)
Rigid gas permeable lenses are smaller gas-permeable lenses that are easy to insert and remove and can provide excellent vision. They move slightly with blinks and allow maximum oxygen to get to the eye.
3.) Hybrid Contact Lenses
Hybrid contact lenses are comprised of a rigid gas permeable lens in the center and a soft contact lens "skirt" surrounding the lens. This can aide in helping the lens center and making them more comfortable.
4.) Custom Soft Contact Lenses
In some, usually mild, cases, patients with keratoconus are able to see well with custom soft contact lenses. These lenses are special designed and ordered instead of being "commercially available". The thickness of the lens helps to minimize irregularities in the cornea.
Q: WHAT IS THE NEXT STEP FOR ME AS A PATIENT?
A: The contact lens fitting process starts with a Specialty Contact Lens Consultation. This consultation covers all testing necessary to determine the best option to perfect your vision. You may try on different types of lenses at this examination as well to assess your visual potential.
If you decide to proceed with contact lenses, the lenses are ordered for you and you will return in about 1-3 weeks to try on the initial lens. This initial lens is our first chance to see how things look. If the lenses looks good you will leave with the lenses and return for a follow up visit to give us feedback on comfort and vision. We may need to alter the lens at this visit and will order lenses with different parameters.
For specialty contact lenses, once we start the fitting process you are able to return for unlimited follow ups and lens changes for three months until we have a final product.
Q: HOW LONG DO THE LENSES LAST?
A: Soft lenses can last anywhere from 1-day (dailies) to months before they need to be exchanged for a new lens.. Rigid lenses, which tend to be more common for specialty patients, can last years as long as the shape of the eye or the prescription needed doesn't changing.
RGP or Scleral lenses are highly customized to the shape and prescription of your eyes. These lenses will not need to be replaced as long as they continue to fit and the plastic does not become scratched.
Our office recommends having a backup pair of specialty contact lenses, especially if you rely on these lenses to see. If nothing has changed, we recommend a new pair of rigid lenses every two years.