Keratoconus is a rare, progressive disease that affects the cornea, which is the clear, transparent layer at the front of the eye. Your cornea is the transparent, outer lens of your eye, and it typically has a smooth dome shape.
In keratoconus, your cornea begins to become thinner than normal, causing it to bulge outward in a “cone” shape, which alters your eyesight in different ways. As the cone shape forms, your normally smooth corneal surface becomes wavy, called irregular astigmatism. Additionally, vision becomes increasingly nearsighted. Focusing becomes impossible without eyeglasses or contact lenses. Usually, the problems begin in one eye and develop later in the other eye too. Typically, your eyeglass prescription will change often as the vision becomes worse and regular contact lenses will be difficult to wear due to discomfort and improper fit.
When keratoconus becomes more severe (which usually takes a long time- however on occasion can happen rather quickly), the cornea can begin to swell and form scar tissue. This scar tissue can result in even further visual distortion and blurred vision.
Keratoconus is an extremely frustrating condition for patients. Symptoms of keratoconus include:
- Blurred vision
- Streaking of lights
- Halos around bright lights at night; glare
- Sudden change of vision in only one eye
- Objects appear distorted, both near and distant
- Double vision from just one eye
- Ghost images
The first line of treatment is usually new prescription eyeglasses. As keratoconus progresses, glasses and soft contact lenses may no longer correct vision and soft lenses may become uncomfortable. If this solution doesn’t help you achieve good vision, then specialty contact lenses are the treatment of choice to provide clear, comfortable vision in patients with keratoconus. Rigid, gas permeable lenses are typically prescribed.
At the more advanced stage of keratoconus, rigid gas permeable (RGP) contact lenses or scleral lenses may be used for increased comfort and vision. Since they are more rigid, RGP and scleral lenses are able to create a smooth, round shape around the cornea, creating a smoother surface for better vision.
Scleral lenses have a larger diameter which covers the entire cornea and reaches over into the white part of the eye, which is known as the sclera. Many patients find these more comfortable than regular RGPs since they move around less when the eyes move. 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.
Whether it is glasses or contact lenses being used to correct vision, patients will likely have to undergo many tests and prescription changes as their vision needs to change.
Other treatments for keratoconus:
Cornea collagen crosslinking is another therapy that has shown to be effective in slowing the progression of keratoconus. As a last resort, a cornea transplant may be performed. During this procedure, the center of your cornea will be removed and replaced with a donor cornea. The new cornea is stitched into place, and you’ll need to wear contact lenses for adequate vision after the surgery.
Corneal cross-linking is a procedure which involves special eye drops and an ultraviolet (UV) light, which are used to strengthen the corneal tissue. This can make the cornea flatter and prevent it from further developing into a cone shape.
How Does Collagen Cross-Linking Help My Keratoconus?
Collagen Cross-Linking, or CXL, is considered an ideal treatment for Keratoconus because the procedure flattens and strengthens the cornea, helping to prevent further thinning and bulging.
CXL is most effective in patients who have been recently diagnosed with Keratoconus. That is because as the condition advances, the more difficult it is to manage. While it does not reverse the corneal shape completely, it can slow down the Keratoconus progression. In most cases, the patient will still need some type of vision correction assistance, such as eyeglasses or contact lenses.
Overview of contact lens options for keratoconus patients:
1.) Scleral Lenses
Scleral lenses are large gas-permeable (rigid) lenses that are able to vault over the entire cornea. 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 no contact or rubbing of the cornea. 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 help the lens center and make 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 specially designed and ordered instead of being “commercially available”. The thickness of the lens helps to minimize irregularities in the cornea.
What happens next as a patient interested in specialty contact lenses?
The contact lens fitting process starts with a Specialty Contact Lens Consultation. This consultation covers all testing necessary to determine the best options to perfect your vision. You may try on different types of lenses at this examination as well to assess your visual potential and what is most comfortable.
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 and get all necessary training on how to care for your new lenses. This initial set of lenses is our first chance to see how things look.
If the lenses look 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. An initial fitting typically takes anywhere between 1 to 3 months to complete all visits.