Keratoconus: 10 treatment options
What is keratoconus?
Keratoconus is a progressive disease of the cornea of the eye that results in distorted vision and vision loss. The disease causes the cornea to gradually become thinner and bulge outward into a cone shape. Keratoconus usually begins between the ages of 10 and 25 and can get progressively worse for 10 years or longer. It can occur in one or both eyes.
Keratoconus signs and symptoms
Symptoms of keratoconus include:
What causes keratoconus?
Research suggests keratoconus may be due to an imbalance of enzymes within the cornea. This imbalance makes the cornea more susceptible to oxidative damage from compounds called free radicals, causing it to weaken and bulge forward.
Risk factors for oxidative damage and weakening of the cornea include a genetic predisposition. This explains why keratoconus often affects more than one member of the same family.
Keratoconus also is associated with:
Overexposure to ultraviolet rays from the sun
A history of poorly fitted contact lenses
Chronic eye irritation
Keratoconus treatment: 10 options
In the mildest form of keratoconus, eyeglasses or soft contact lenses may help. But as the disease progresses and the cornea thins and becomes increasingly more irregular in shape, glasses and regular soft contact lenses no longer provide adequate vision correction.
Keratoconus treatment options include:
1. Corneal crosslinking
This procedure (also called corneal collagen cross-linking or CXL) strengthens and stabilizes the cornea.
There are two versions of corneal crosslinking: epithelium-off and epithelium-on.
With epithelium-off crosslinking, the outer layer of the cornea (epithelium) is removed. Riboflavin, a type of B vitamin, is then applied to the underlying corneal tissue (stroma) and is activated with UV light.
With the epithelium-on method (also called transepithelial crosslinking), the corneal epithelium is left intact during the treatment.
Advantages of epithelium-on CXL include:
Less risk of infection
Faster visual recovery
Corneal crosslinking is often effective at stabilizing the cornea and successfully managing keratoconus. It also is being investigated as a way to treat or prevent complications following LASIK and other vision correction surgery.
Corneal crosslinking also can be combined with other keratoconus treatment options. For example, mild to moderate keratoconus has been safely and successfully treated with a combination of CXL and Intacs corneal implants (see below).
2. Custom soft contact lenses
Specially designed custom soft contact lenses are sometimes effective to manage vision problems caused by mild to moderate keratoconus. These lenses are made-to-order based on detailed measurements of the person's keratoconic eye(s). Custom soft lenses may be more comfortable than gas permeable lenses (GPs) or hybrid contact lenses for some wearers.
In the United States, custom soft contacts that are available for the correction of keratoconus include:
NovaKone lenses (Bausch + Lomb). These medium-water hydrogel lenses can correct up to 30 D of nearsightedness or farsightedness and up to 10 D of astigmatism.
Both lenses have a very wide range of fitting parameters for a customized fit. They are larger in diameter than regular soft lenses for greater stability on a keratoconic eye.
Custom toric soft contacts for keratoconus cost significantly more than regular soft contacts. But vision insurance may cover some of the costs associated with contact lenses for keratoconus.
3. Gas permeable contact lenses
Gas permeable (GP) contact lenses usually are the preferred treatment for mild to moderate keratoconus. GP lenses vault over the cornea, replacing its irregular shape with a smooth, uniform refracting surface to improve vision.
Fitting contact lenses on an eye with keratoconus often is challenging and time consuming. Expect frequent return visits to your eye doctor to fine-tune the fit — especially if your keratoconus continues to progress.
4. "Piggybacking" contact lenses
Wearing gas permeable contact lenses for keratoconus can sometimes be uncomfortable. To provide greater comfort, some eye doctors recommend "piggybacking" two different types of contact lenses on the same eye.
This technique usually involves fitting a silicone hydrogel soft contact lens on the eye and then fitting a GP lens over it.
This approach increases wearer comfort because the soft lens acts like a cushioning pad under the rigid GP lens.
5. Hybrid contact lenses
Hybrid contact lenses have a very oxygen-permeable rigid center surrounded by a soft peripheral "skirt." The central GP zone of the lens vaults over the cone-shaped cornea for increased comfort.
Examples include UltraHealth and ClearKone hybrid contact lenses manufactured by SynergEyes.
Hybrid contact lenses offer both the crisp optics of a GP contact lens and comfort similar to soft lenses, according to SynergEyes. UltraHealth and ClearKone lenses are available in a wide variety of parameters to provide a a custom fit for keratoconic eyes.
6. Scleral and semi-scleral lenses
Scleral and semi-scleral contact lenses are large-diameter gas permeable lenses that cover the entire cornea and extend onto the "white" of the eye (the sclera).
Scleral lenses cover a larger portion of the sclera, whereas semi-scleral lenses cover a smaller area.
Because the center of scleral and semi-scleral lenses vaults over the irregularly shaped cornea, these lenses don't apply pressure to the eye's cone-shaped surface for a more comfortable fit.
These large GP lenses also are more stable on the eye than conventional gas permeable contact lenses, which move with each blink because they cover only a portion of the cornea.
7. Prosthetic lenses
Eyes with advanced keratoconus may require an advanced prosthetic scleral lens design.
An example are lenses made with the EyePrintPRO process (EyePrint Prosthetics). This system uses proprietary Elevation Specific Technology to exactly match the unique irregularities of each individual eye.
The process begins with an EyePrint Impression, which captures the precise curvatures of the entire ocular surface. Doctors then send the resulting impression to an EyePrint lab for 3-D scanning.
The scanned data is then fed to a numerically controlled machining system. This system produces a lens that matches the impression exactly and therefore fits the individual cornea and sclera perfectly.
"The EyePrint is like a fingerprint—it's completely individual," says EyePrint developer Dr. Christine Sindt, Clinical Associate Professor of Ophthalmology and Visual Sciences at University of Iowa.
The EyePrintPRO process can only be used by doctors who undergo specific training and certification. To learn more and to find an eye doctor who prescribes and fits these prosthetic lenses, visit the EyePrint Prosthetics website.
Intacs are FDA-approved clear, arc-shaped corneal inserts that are surgically positioned within the peripheral cornea to reshape the front surface of the eye.
Intacs may be needed when keratoconus patients no longer can obtain functional vision with contact lenses or eyeglasses.
Several studies show that Intacs can improve the best spectacle-corrected visual acuity (BSCVA) of a keratoconic eye by an average of two lines on a standard eye chart. The implants also have the advantage of being removable and exchangeable. The surgical procedure takes only about 10 minutes.
9. Topography-guided conductive keratoplasty
Early results of a small study involving topography-guided conductive keratoplasty (CK) show this procedure might help smooth corneal irregularities caused by keratoconus.
Topography-guided CK uses energy from radio waves, applied with a small probe at several points in the periphery of the cornea to reshape the eye's front surface. A topographic "map" created by computer imaging of the eye's surface helps create individualized treatment plans.
SEE RELATED: Corneal topography
10. Corneal transplant
Some people with keratoconus can't tolerate a rigid contact lens, or they reach the point where contact lenses or other therapies no longer provide acceptable vision.
The last remedy to be considered may be a cornea transplant, also called a penetrating keratoplasty (PK or PKP). Even after a transplant, you most likely will need glasses or contact lenses for clear vision.
Page published in March 2019
Page updated in September 2021