What is Keratoconus? To understand Keratoconus, one must first understand the anatomy of the eye. The eye has a clear dome on the front, kind of like the crystal on a watch. This clear dome is called the cornea and works as a lens to the eye, to focus images in the eye and allow us to see. Since it is a lens, it must be 1) Transparent and 2) Smooth of regular curvature. In some people, this is not the case. The cornea is irregular in shape or even scarred and not transparent. One disorder that has an irregular cornea is called Keratoconus, and results because the cornea is weak in some way. The cornea then bulges forward and becomes irregular, bumpy in shape. You can imagine that a lens of this sort would not focus a camera well, and also in Keratoconus, the bulging cornea focuses a very blurry image. In mild cases, glasses may correct the problem, or more usually, contact lenses. Why are contact lenses needed? A hard or gas permeable lens will mask the irregular cornea in Keratoconus and act as a smooth lens for the eye. The problem is, that the cornea in Keratoconus can become steeper and more irregular with time. This makes it difficult to fit a contact lens, sort of like trying to balance a flat plate on top of a pencil. This makes the contact lenses uncomfortable and makes the wearing time too short for some people to accomplish their daily work and interferes with their life activities.

At this point, other options need to be considered. Until a few years ago, the only option was a corneal transplant, more about that later. But a French Ophthalmologist realized that Intacs might help people with Keratoconus. What are Intacs? They are tiny clear plastic rings that are inserted into the cornea. They were originally developed to treat near-sightedness (myopia). They worked for this, but Lasers came along, and they have turned out to be much, much better for treating near-sightedness. Dr. Colin thought they might help people with Keratoconus and was brave enough to try it. How do they work? They regularize the cornea. This means that the steep, irregular part of the cornea becomes more regular and focuses better. Do they give 20/20 perfect vision? No, definitely not, they don’t work like LASIK or PRK in a normal person to restore vision without correction. But, Intacs do improve quality of vision and improve quality of comfort with glasses or contact lenses. They push the “cone” part of the cornea toward the center, so the person can look through a better focusing part of the cornea.

Are they for all Keratoconus patients? No, they are not, the studies show that they are helpful in moderate Keratoconus and improve sight with glasses or contact lenses in 80% of patients with Keratoconus that are good candidates. If they don’t work, they don’t make the vision worse, and can be removed if needed. How are they inserted? We use the IntraLase laser to help with the insertion. The Laser makes millions of microscopic, tiny gas bubbles in the cornea. The bubble pattern is computer controlled and extremely accurately focused. The shape can be any configuration we want, and is amazing to use to create a round channel so the Intac ring can be inserted. It is quick and painless. The Intacs are so beautiful to look at, like diamonds suspended in the cornea.

What is the vision like afterward? The final result is not known for 3-6 months after the surgery, but the majority of people notice a big improvement even one day after the surgery. A stitch is usually put in place at the end of surgery and this stays for 1-2 months. The vision usually improves after the stitch is painlessly removed in the office. Sometimes, a temporary glasses prescription is needed. Generally, a permanent prescription for glasses or contacts can be fit after 3 months. Sometimes it is necessary to remove one or two ring segments, and this can be done easily. It does not hurt to put the Intacs in or to remove them. The eye is frozen with drops and the segments are carefully slid in or out of their channel. The procedure is minimally invasive, which means that very little is done to the eye, and if the Intac is removed, the cornea will usually revert to its original shape.

What if I am not an Intac candidate, or the Intacs don’t work for me? If they don’t provide a satisfactory improvement, then other options can be considered, and are not prevented by the Intacs operation. I am referring to a corneal transplant. What is a corneal transplant? Keratoconus usually affects the center of the Cornea, that clear dome that I wrote about above. If the Keratoconus is too advanced, then the center of the Cornea needs to be replaced, that is a corneal transplant is done. A transplant, isn’t that a major operation? Yes in a way, and is far more serious than the Intac procedure, but when done in proper circumstances is very successful for people with Keratoconus. In fact, it has been the only surgical treatment available for people who can no longer wear contact lenses for Keratoconus. The Corneal transplant procedure has been around for a century and is performed 50,000 times a year in North America. If you look at the cornea from the side, it is only one half a millimeter thick and is made up of 3 layers, kind of like an Oreo cookie, with an outer wafer, and middle filling and an inner wafer. In usual corneal transplants, all three layers are replaced after being cut out with a circular blade, called a trephine.

What are some of the newer options for corneal surgery for Keratoconus? As mentioned above, we usually have to take out all the layers of the cornea and replace them with a donor cornea. Yet, in Keratoconus, the inner layer is normal, it is the middle layer and outer that are not normal. Techniques have been developed to allow us to retain the inner layer. The advantage of this is that the inner layer is very important to the health of the cornea, it is the “water pump” of the eye and keeps the cornea clear. Also, corneal transplants can reject, they are foreign tissues, like a heart or lung or kidney transplant. It is this inner wafer that is most likely to reject and when it does, the cornea becomes swollen and need to be replaced. By retaining the person’s inner layer of the cornea, we not only keep the structure of the eye more intact, but reduce the chance of rejection, and if rejection does occur, it is easily treated and reversed. This type of transplant is called a Deep Anterior Lamellar Transplant or DALK. We can’t do it in all cases, but when we can, it is preferable, in my opinion. If not possible, a standard corneal transplant of all three layers of the Cornea is a great solution with a 50 year track record. Rejection occurs only in 5% of cases and people with Keratoconus do very well with a transplant. Most achieve good vision with glasses or contact lenses after a transplant.

What is really exciting is the development and use of new lasers called Femtosecond Lasers to make corneal transplants much better. The same laser, the IntraLase, mentioned above in connection with Intacs, can be used for Corneal Transplants as well. Yonge Eglinton Laser is the first place in Canada to have adopted this technology and our results have been outstanding to date. What are the advantages of having a transplant with the IntraLase? A regular, traditional transplant cuts the cornea with a straight blade and the total surface area of the healing area is only 4 square millimeters. The IntraLase allows us to make custom shapes to the cut on the cornea. We can make a square joint, a rabbet joint, a tongue in groove joint and increase the surface area of healing 9 times! This results in much faster healing and a stronger bond between the donor cornea and the person’s own cornea. The Laser etches alignment marks to help the surgeon place the sutures more precisely. This is truly revolutionary technology and I believe is the better way to do corneal surgery. In five years, I believe it will come to replace all standard corneal surgery.