I had this interesting question from Sophie:

Dear Mr. Allamby, My father has keratoconus, I believe he has had it a long time but was diagnosed officially at an eye test when he was 30 (he is now 50) will this affect my chances of laser eye surgery and would it be safe to proceed if I show no current symptoms (I am 21).

Many thanks, Sophie

Dear Sophie, Thanks for your question. Keratoconus (KC) is most often sporadic (not apparently inherited) but has been observed to run in some families. Typically it is first seen in adolescence. Around 80% of cases do not progress. As you are now 21, if you have KC there may well be changes in the corneas already so the best next step would be to see you for corneal scans. These are now very sophisticated at picking up even early changes of KC before they would affect your vision.

We perform thin-flap femtosecond LASIK with our new Crystal Line Ziemer down to 500 microns central corneal thickness (CCT). Below that we would normally do PRK, and also PRK if there is any slight irregularity in corneal shape. However, it is the appearance on the scans that is more important in your case, and CCT is only one of the risk factors we look at when considering suitability.

I am rather obsessed with safety, and any doubt whatsoever means I would advise against any treatment, even if you were very keen!

IMPORTANT NEWS for those people considering having LASIK laser eye surgery.

There appears to be a fundamental difference between LASIK flaps cut either with a blade or created with a laser. Laser created flaps mean a safer surgery as the results are more accurate, so fewer enhancements needed, and the eye is left stronger.

Making a replaceable flap is the first part of the LASIK procedure, just prior to reshaping the cornea to correct vision. Until recently (and still in many clinics) the flap was made by a physical cut with a very sharp razor blade contained within a precision device. However several clinics and the major three chain operators have invested in femtosecond lasers to create the corneal flap without the need for a blade.

This is known as blade-free LASIK, dual laser LASIK, Z-LASIK or IntraLASIK depending on which clinic you are talking to.

We know that thicker flaps cut with a blade do not fully heal and can be lifted up surgically even many years later. Traditional blade flaps are thicker and cut deeper into the cornea. However laser flaps are thinner and leave the eye stronger afterwards.

However a key difference highlighted by Professor John Marshall in London is that because these very thin laser flaps pass through near the surface of the cornea where the collagen is different from deeper down, they actually heal down and are not able to be lifted later on. This means the eye regains strength again with a laser flap, but not with a blade flap.

Newer blade machines have been introduced in 2008 and 2009 that cut thinner flaps to compete with the thin femtosecond laser flaps which should benefit from the better healing seen in sub-120 micron flaps

My recommendation to you when choosing a clinic is to be able to select to have a femtosecond laser procedure at a clinic that has that technology. They are more expensive than blade procedures (expect to pay around £300 more per eye) but well worth the likelihood of a long-term increase in safety.