Keratoconus and ectasia create an irregular cornea that
can be treated with Intacs inserts and/or CxL.
UVA light is applied in precise amounts using a specialized
goggle with LED lights.
The theory behind CxL treatment is that the fibrils of the
keratoconus cornea lose their ability to link to each other.
CxL treatment causes more cross-linking of the fibrils,
making the cornea stronger.
The image shows a map of an eye with keratoconus. The off-center
red and yellow area shows the forward bulging due to keratoconus.
Intacs are tiny plastic rings surgically added to the cornea.
CxL and Intacs can resolve a significant amout of keratoconus and corneal instability.
A developing keratoconus and keratectasia treatment is Corneal Collagen
Crosslinking with Riboflavin (CxL), that has been proven outside
of the US to strengthen a weakened corneal structure. US Food and Drug Administration CxL studies in the United States were halted in June 2010 for reasons that do not relate to efficacy. Several doctors currently provide CxL as an off-label use of Riboflavin (vitamin B2). Several US study groups continue to measure the efficacy of CxL. For more
information, visit CxL Clinical Studies.
Increase Tissue Anchors
This method works by increasing collagen crosslinking, which
are the natural "anchors" within the cornea. These anchors are responsible
for preventing the cornea from bulging out and becoming steep and
irregular, consequence of advanced keratoconus.
Keratectasia occurs when the integrity of the cornea is compromised during surgery such as Lasik. Studies have shown that a health cornea will remain stable if at least 250 microns of corneal tissue remains untouched. Ectasia occurs when the cornea is health or too little cornea remains untouched. Ectasia presents as symptoms of progressive refractive error as the cornea bulges forward due to intraocular pressure within the eye. Ectasia is largely preventable in Lasik, Bladeless Lasik, PRK, LASEK, and Epi-Lasik surgery by diligent evaluation of the health of the eye and amount of tissue to be removed during refractive surgery, however ectasia may occur absent other know indicators.
CxL treats refractive surgery induced ectasia by strengthening the cornea and effectively making it stiffer to withstand the intraocular pressure associated with forward movement of the cornea.
Quick In-Office Procedure
The 30-minute corneal crosslinking treatment is performed in
the doctor's office. During the treatment, custom-made Riboflavin
eye drops are applied to the cornea, which is then activated by
ultraviolet light. This amazingly simple process has been shown
in laboratory and clinical studies to increase the amount of collagen
cross-linking in the cornea and strengthen the cornea. In published
European studies, such treatments were proven safe and effective
Keratoconus is a disease of the cornea that makes the cornea
become weak and may gradually bulge outward. Most often, this bulging
is in the lower half of the cornea and first presents as astigmatism, however not all astigmatism is due to keratoconus.
In mild or early stages of keratoconus (forme fruste keratoconus),
eyeglasses may correct the astigmatic vision.
The abnormal curvature of the cornea due to keratoconus changes
the cornea's refractive error producing moderate to severe blurriness of
vision. As keratoconus advances, rigid gas-permeable (RGP) contact
lenses maybe the only non-surgical way to achieve clear vision.
If keratoconus continues to advance, scarring of the central cornea
Approximately half of keratoconus patients have no negative lifestyle
effects beyond corrective lenses. The cornea stabilizes after a
few years without ever causing severe vision problems. For others,
the only resolution to keratoconus has been PKP, with a long healing period and unpredictable refractive
error. Even after corneal transplant PKP, keratoconus can reoccur
in the new donor cornea. Fortunately, there are two new methods
to treat keratoconus that are much less invasive than a corneal
CxL for Keratoconus
European and US clinical studies have shown that CxL reduces the progression of Keratoconus and in some cases reduced the forward vaulting by strengthening the corneal tissue.
Intacs for Keratoconus
An established treatment for keratoconus is Intacs.
Intacs are a medical device approved by the FDA for the correction of 1.00 to 3.00 diopters of myopia (nearsighted, shortsighted) and virtually no astigmatism. Intacs inserts are the only refractive surgery
procedure that adds structural integrity to the cornea. This
unique attribute made Intacs an ideal treatment for keratoconus.
Intacs are clear small semicircular plastic rings of various
thickness that are inserted within the cornea at its outer edges.
Insertion of these rings flatten the central area of the cornea
and correct myopic refractive error. A major advantage of Intacs is that no tissue
is removed and there is no ablation or incision across the visual axis.
Intacs surgery is not truly reversible because of the incision,
but the Intacs can be completely removed or exchanged for a different
size. Intacs inserts cannot be felt by the patient and are no more
visible than a contact lens. After insertion and healing, Intacs
require no maintenance.
The placement of Intacs inserts remodels and reinforces the cornea,
eliminating some or all of the irregularities caused by keratoconus.
Follow-up visits will be required to monitor the healing process
and to evaluate the visual benefits of the procedure. Even after
a successful Intacs procedure for keratoconus, glasses or contacts
may be required, however Intacs have been shown to improve vision
and reduce or stop the progression of keratoconus, thereby saving
the patient from needing PKP.
Intacs have been approved for the treatment of keratoconus by
the FDA under a Humanitarian Device Exemption (HDE) Humanitarian
Use Devices (HUDs) are medical devices specially designated by the
FDA for use in the treatment of fewer than 4000 patients per year
with rare medical conditions.
CxL and Intacs
Corneal crosslinking treatments can be combined with Intacs to
flatten the keratoconus cone even more than with Intacs alone. In
these cases, corneal crosslinking treatments stabilize keratoconus
from getting worse as well as help the Intacs reverse the keratoconus
steepening that had already occurred.
Looking For Best Lasik Surgeon?
If you are ready to choose a doctor to be evaluated for conventional
or custom wavefront Lasik, Bladeless Lasik, PRK, or any refractive surgery procedure, we recommend you consider a doctor who has been evaluated and certified by the USAEyes nonprofit organization.
Locate a USAEyes Evaluated & Certified Lasik Doctor.
If this article did not fully answer your questions, use our
free Ask Lasik Expert patient forum.