What is Keratoconus?
Keratoconus is a degenerative non-inflammatory disorder of the eye in which structual changes within the cornea cause it to thin and change to a more conical shape than its normal even curve. Keratoconus can cause substantial distortion of the vision, with multiple images, streaking and sensitivity to light all often reported by the patient. Though frequently thought of as a rare condition, keratoconus is the most common dystrophy of the cornea, affecting around one person in a thousand, and seems to occur equally in all ethnic groups worldwide. It is typically diagnosed in the patient’s adolescent years and attains its most severe state in the twenties and thirties.
Progression of Keratoconus
Keratoconus is a little-understood disease with an uncertain cause, and the course of its progression following diagnosis is unpredictable. The associated deterioration in vision, if in both eyes, can affect the person’s ability, for example, to drive a car legally. It does not, however, lead to blindness, and in most cases, corrective lenses are effective enough to allow the patient to continue to drive and likewise function normally. Further progression of the disease may lead to a need for surgery. A condition called post-LASIK ectasia (PLE) is a rare occurrence after LASIK which is treated the same as keratoconus.
Treatment of Keratoconus
Roholt Vision Institute specializes in treatment of keratoconus. Dr.’s Mathie and Lawrence perform contact lens fits for difficult keratoconus cases. In the event that contact lenses are not effective Dr. Roholt can perform corrective surgery.
Intacs for Keratoconus
Intacs are clear, thin prescription inserts placed in the periphery of the cornea (under the surface) by an ophthalmologist during a brief outpatient procedure. Intacs for the treatment of keratoconus is an FDA approved procedure.
How do Intacts Work?
Intacs reshape the curvature of the cornea from within, enhancing the natural shape of the eye to correct mild nearsightedness. Because no tissue is removed, natural optics are enhanced and adds to the structural integrity of the cornea.
A curved glide creates a channel in the periphery of the cornea by gently separating the tissue layers. Tiny plastic segments (Intacs) are placed in the channel much like placing a pencil in between the pages of a book. This causes the cornea to flatten which help to achieve more clear vision.
In keratoconus, the Intacs will usually imporve the uncorrected vision, and/or allow resumption of contact lens. The procedure is less invasive than corneal transplantation, and may delay progression of keratoconus. The Intacs are removable.
Ideal Candidates for Intacs
Not everyone with keratoconus will be a candidate for the Intacs procedure. Dr. Roholt was the first in Ohio to implant Intacs and the first to use this device for keratoconus and post-LASIK keratoconus ectasia. For his out-of-town patients, Dr. Roholt can review chart notes ahead of time to make a preliminiary determination as to whether Intacs may be beneficial. For more information see www.intacsforkeratoconus.com.
Corneal Collagen Cross-Linking
This procedure has been shown to be very effective at slowing the progression of keratoconus. Corneal cross-linking (CXL) is a 15 minute office procedure that strengthens the cornea if it’s been weakened by keratoconus or other corneal disease. It’s use in LASIK or PRK is currently being studied; rarely it can be helpful after LASIK if the cornea seems to be unstable.
How Does Corneal Cross-Linking Work?
The minimally invasive CXL procedure involves applying liquid riboflavin (vitamin B2) to the surface of the eye, followed by treatment with a controlled application of ultraviolet light, to eliminate corneal ectasia or weakness.
Different Types of Corneal Cross-Linking
The two basic types of corneal cross-linking are:
- Epithelium-off CXL. In this type of cross-linking procedure, the thin outer layer (epithelium) of the cornea is removed to allow the liquid riboflavin to more easily penetrate the corneal tissue.
- Epithelium-on CXL. In this procedure (also called transepithelial CXL), the protective corneal epithelium is left intact, requiring a longer riboflavin “loading” time.
Combining Corneal Cross-Linking with Other Procedures
Corneal crosslinking also can be combined with other procedures for keratoconus treatment. For example, combining CXL with implanting tiny arc-shaped corneal inserts called Intacs has been shown to help reshape and stabilize the cornea in more advanced cases of keratoconus.
The Cross-Linking (CXL) would ideally be applied early in the disease or when progression (worsening) is occurring.