Steve asked about cTen laser correction:

Hi Dave. Thanks for providing this blog, in anticipation of surgery it’s very much appreciated.
I’ve heard of a superioir procedure called CTen which seems to be a significant advance in corrective eye surgery, but can’t find any providers. Can you shed any light?

The cTen system is from an Italian company called iVis Technologies. It incorporates a 1,000-Hertz excimer laser (iRES) and a software planning system called CIPTA. cTen is an acronym for Customised, TransEpithelial, No-touch surgery.

It is promoted for complex cases where there is irregularity of the cornea, e.g irregular astigmatism. They use the excimer laser to remove the epithelial skin layer and use topography information from a Scheimpflug camera scanner to correct imperfections across the cornea stroma. The makers suggest this is a bette way of performing PRK.

Not really a significant advance as all this technology is currently available. We use the same Scheimpflug approach already with our WaveLight laser in its T-CAT (topography guided) mode, and all lasers can be used to remove the epithelium down to a desired depth the leave a smooth surface.

For virgin unoperated eyes, there is no significant benefit to use the CIPTA platform. The procedure here is just PRK. Also, the no-touch laser removal of epithelium approach adds little, as standard alcohol based removal is quick, effective and predicable, and is used around the world as standard. I do agree with iVis that topography guided correction is most useful for irregular corneas over wavefront guided, and I use T-CAT for these complex cases.

The above helps explain why you can’t find any providers. The gold standard procedure for us is thin flap femtosecond Z-LASIK. If we need to do surface laser, we do PRK.