Dishler Laser - Blog

What is a femtosecond and why is that important?

August 29, 2009 @ 06:28 PM — by Jon Dishler
Light is the fastest thing we know of, it travels 186,000 miles in just one second. And the distance to the sun is reached in under 10 minutes at light speed. A femtosecond is a unit of time, a tiny piece of a second. It is 10 to the -15 power seconds or 1/100000000000000 of a second. How small you might wonder is that, well in a femtosecond that same beam of light that can travel around the earth 25 or so times in a second, travels just a third of a micron in a femtosecond. This means that in 1000 femtoseconds, light travels 300 microns or about 1/3 of a millimeter -- those tiny little gradations on the ruler you can barely see! This is less than the thickness of a credit card in 1000 femtoseconds, and we have a laser that has pulses so short, that they are only a few hundred femtoseconds. This means that the laser is shooting out pulses of light, or photons, in packets that span just a tiny fraction of a millimeter, light photon bullets and these tiny light bullets are what makes femtosecond LASIK possible. The "bullet" is only a micron in size and has very low energy, but when focused at the proper spot will create a very tiny break in the tissue of the cornea. When combined with hundreds of thousands of similar spots, it allows surgeons to cut a precise plane in tissue in a way that is more exact than the precision of any other kind of cutting of tissue that exists. All this techno-talk means that a femtosecond laser can do what no laser has ever been able to do before. It is light years beyond cutting with a scalpel. It is the right tool for the job.

Blade free LASIK is better LASIK

August 21, 2009 @ 09:19 PM — by Jon Dishler
To say bladeless LASIK is the gold standard, or the standard of care are strong statements subject to interpretation. What I can say is that since introducing bladeless LASIK to Denver Colorado in 2001 we have progressed to a point that in the last several years we only offer bladeless to our patients because we believe it is a much better way to do LASIK. There are several reasons for this. First there has been shown to be less dry eye problems due to the increased gentleness of the procedure. There are also less risks of other serious complications such as loss of suction resulting in a partial or abnormally cut flap. These complications do occur with a microkeratome but are virtually nonexistent with the all laser method. Studies have been performed that show the results are better with the blade free method which may have something to do with how exact the cutting of the flap has been with the laser as compared to a blade. Finally there is the accuracy of depth which is far greater with the all laser procedure than the blade procedure. All of these reasons probably account for the fact that now about 50% of all LASIK is blade free. The only reason not to have all blade free is cost, and it seems that the extra cost is worth it for all of these reasons. Since blade free is so much more common, you can find centers to offer this at no or little additional cost from standard LASIK. This has advanced even more with the VisuMax, now our preferred blade free LASIK procedure and here is why.