Over the many years that I have been taking care of keratoconus patients, I have heard of and read many theories about the causes of KC and the “best” treatments for helping patients affected by this condition. The following are some of the misconceptions about keratoconus and my thoughts about this often frustrating condition:
It has been agreed upon by a number of university studies that keratoconus has a genetic origin. Eye rubbing, ultraviolet light from the sun and allergies may contribute to this condition, but the underlying cause is genetics.
Over a 20 year period, from 1994 through 2014, I have treated several thousand patients suffering vision loss due to keratoconus. Many of these patients had very advanced cases of KC. Over these years about 20 patients needed to undergo corneal transplant surgery. This is due to the surge in better non-invasive technologies such as scleral lenses to better address the many issues that the KC population faces. In addition, new diagnostic technologies such as Optical Coherence Tomography allows us to be extremely accurate when designing specialty lenses for various types of keratoconic corneas.
Keratoconus usually starts after puberty or in the early teenage years. Both eyes are usually affected but not to the same extent. The active period of keratoconus lasts for around 5 years. Minor changes to the corneal shape (topography) may take place after this active period. This is normal. Minor changes to the corneal topography may take place in corneas not affected by keratoconus. Minor changes to the “stable” keratoconic cornea may also take place regardless if Collagen Cross-linking is done or if intra-corneal rings (Intacs) are surgically implanted into the cornea.
In recent years, a number of new technologies have been developed to allow patients with advanced keratoconus obtain functional vision once again. There include a number of soft lenses specifically designed to allow KC patients who cannot tolerate a rigid lens to obtain clearer vision. For patients who cannot obtain satisfactory vision with a specialty soft lens design, the best option will be a scleral lens. This technology is explained on: WWW.SCLERALLENS.COM. The comfort patients experience with a scleral lens is comparable to the comfort of a soft lens and often exceeds the comfort of a soft contact lens.
Studies have shown this to be true but only if the KC patient is in the active stage. The main purpose of Collagen Cross-Linking is to stablize the keratoconic cornea, not to improve the patient’s vision. If a keratoconic patient is in their teenage years or early 20’s, progression of their keratoconus is more likely than a patient with KC who is their 40’s. The best way to determine keratoconic progression is to have serial corneal topographies taken with the same corneal topographer and by the same instrument operator. If you are concerned about KC progression, I recommend that this be done at 6 month intervals over several years. It is extremely rare for significant changes to the corneal shape (topography) to take place in the space of 5 or 6 months. If progression is truly taking place, the best course of action will be Collagen-Cross linking. Again, it has been my experience after having taken care of many thousands of patients with keratoconus, that keratoconus in the active phase, progresses slowly. Of course, there are exceptions to every rule. For this reason, when given a diagnosis of keratoconus, the patient should not panic and seek out aggressive treatments.
Keratoconus develops due to genetics. Keratoconus after LASIK is called post-LASIK corneal ectasia. The corneal topographies may appear to be the same as the corneal topography of a KC cornea. However, the cause is different and the treatment may differ also. It has been my experience that this condition develops between 18 months to many years following LASIK surgery. The reason for this is that LASIK surgery severs the fibers (Collagen fibers) that provide stability to the cornea and give the cornea it’s shape. Over the years following LASIK, the weakened “corneal wall” is subjected to pressures from inside the eye. When this intra-ocular pressure becomes overwhelming, the cornea will “buckle” and become distorted. When this happens, the patient will experience a significant reduction in vision in the affected eye. Additional surgeries will not correct this. The best treatment for this will be for this eye to be fit with a scleral lens. One of the reasons for treating this type of eye with a scleral lens is that most post-LASIK corneas are very dry. The scleral lens will allow this eye to see clearly once again and at the same time keep the cornea in a liquid environment. Again, this is explained in the above website. One last bit of information. Over the years I have taken care of hundreds of patients suffering loss of vision due to post-LASIK corneal ectasia. It has been my experience that the unstable “progressive” period lasts from several weeks to several months and does not progress in the same way as genetically created keratoconus.
This is a very simplified explanation of keratoconus. In reality, the steeping of the cornea may occur along any portion of corneal surface. If the KC is “peaked” and occurs in the center of the cornea, it is referred to as a “Nipple cone”. If the steepening occurs in the peripheral portion of the cornea, it is referred to as a “Pellucid” cone. Occasionally we see the entire cornea protruding or bulging. This is referred to as a “Global” cone. There are multiple lens technologies currently available to address the issues that each of these KC corneas present. When visiting a doctor who specializes in treating keratoconus with specialty lenses, you will need patience. A number of lens fittings may be necessary to achieve optimal results.
This is not true. A contact lens that presses onto the keratoconic cornea will eventually be very painful to wear and will scar the cornea. The active period of keratoconus is just that, an active period and putting pressure on the cornea will not stop it from progressing. As I have written above, if there is progression in a patient’s keratoconus, Collagen-Cross linking should be considered.
This is an excellent question. Corneal transplant surgery should be considered when the center of the cornea (along the visual axis) is scarred, opaque or so thin that the patient is experiencing great discomfort or pain. This indeed, is a very rare situation. In cases other than this, every non-surgical option should be considered. A transplanted cornea will usually be very distorted and will require the patient to wear a specialty contact or scleral lens. In addition, anti-rejection eye drops or other medications may be needed to be taken. These medications can have side effects such as cataracts and glaucoma.
There is also the risk of infection and rejection of the corneal transplant which can necessitate another corneal transplant operation. It has been my experience that well trained corneal specialists will do everything possible to help the patient avoid corneal transplant surgery.
Rethink Corneal Transplant Surgery (These are photos of failed corneal transplants. The risks involved with corneal transplant surgery are very real.)