Wouldn’t it be nice if you could walk into the doctor’s surgery with keratoconus and walk out cured?
The ‘quick fix’ or magic bullet is the holy grail of any medical condition but unfortunately these are not as common as we would like. This post explores how laser surgery can and can’t be used in the treatment of this condition.
Lasers can correct vision, right?
Laser eye surgery has been used for the past 30 years to correct short-sightedness, long-sightedness and astigmatism. It relies on the removal of tissue from the cornea to reshape it to provide clear focus without glasses. But, in order to be a suitable candidate for a LASIK procedure, your cornea must be healthy. That’s why people with keratoconus – even mild forms – cannot have LASIK or other cornea procedures. The risk is that it would cause worsening (or progression) of their disease.
What is corneal ectasia?
Ectasia is thinning of the cornea that gets worse over time. It used to be seen in a very small proportion of people who had LASIK vision correction in the past. In retrospect, these patients were not suitable candidates for LASIK, due to their very mild, undiagnosed keratoconus.
These days, the shape of your cornea is very carefully assessed and considered prior to laser eye surgery and post-LASIK corneal ectasia has almost disappeared.
Keratoconus can be present in a sub-clinical form that gives no symptoms. This is called forme fruste keratconus and is more common than the symptomatic form of the disease. Family members of people with full keratoconus may have this very mild form of the disease. The trouble is, their corneas are not normal and if they have laser eye surgery, things can go rapidly downhill. Always tell your laser eye surgeon if you have any family members with keratoconus.
What about combined laser and collagen cross linking?
This is a really interesting idea; corneal collagen cross linking has been shown to effectively halt the progress of keratoconus disease. While it doesn’t cure the disease or reverse the damage, it stops it from getting worse, or slows it right down. This is particularly relevant for people in their teens and twenties when the disease is most active.
Some surgeons offer a combination of collagen cross linking and LASIK to their laser eye surgery patients, in an effort to minimise the chances of ectasia and strengthen the cornea. There are not enough data available at this stage to demonstrate if this has any benefit (or risk) but we do know that cross-linking causes change over time – which is not a good thing if you have just had LASIK.
What about laser for keratoconus patients?
There has been a lot of interest from researchers on a procedure that combines cross-linking with PRK – or surface laser eye surgery, a procedure used for decades to correct short-sightedness and astigmatism. The idea is that rather than just having cross-linking, the keratoconus patient would have a procedure that combined cross-linking and PRK. This would stabilise the disease AND reduce the astigmatism.
Does it work?
A team of eye doctors led by Kanellopoulos conducted a small study (32 eyes) on the combined procedure and found an improvement in vision in the majority of eyes. They also found that having the combined procedure was superior to having two separate procedures for cross-linking and PRK.
However, the study was small and it will require more data to determine if this is a safe procedure to consider.
For now, collagen cross linking has been shown to be effective in slowing or halting the disease. Whether the addition of laser eye surgery will provide a superior outcome is yet to be proven.
