cTen, no-touch PRK and LASIK

| Jul 11, 2010 | Comments 9

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.

Filed Under: PRK • Questions

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About the Author: Mr. Dave Allamby FRCS FRCOphth is a leading London-based laser eye surgeon. You may have seen him on the This Morning TV show with Phillip Schofield and Fern Britton or read one of several articles in the national press, recently for treating Denise Van Outen, rock giant Rick Wakeman and broadcaster Paul Ross. David is Medical Director at Focus Laser Vision, known as a world-leading clinic in the treatment of presbyopia, or age related loss of close vision. Focus Laser Vision is also London's only clinic to offer next-generation Z-LASIK laser eye treatment for short sight, long sight or astigmatism.

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  1. Natasha Vidas says:
    December 1, 2011 at 1:18 am

    Dear Dr Allamby

    I hope this is the right space to ask a question.

    I came in to FOCUS on Monday (28th Nov) for my laser eye surgery assessment (the staff were lovely and really helpful). After all the tests I was told that I have 20/12 vision with my contact lens correction, which is something I suspected but wasn’t sure about. The optometrist explained that not all people can see 20/12 no matter how much one tries to correct their vision with lenses – which is something I didn’t know. She said I was quite unusual in that I have a -5 prescription with 20/12 vision (with lens correction). I was told that the statistics for FOCUS and people obtaining 20/12 after surgery was 49%. I am keen to have the surgery done (and have provisionally booked to have it done next Tuesday 6th Dec at 3pm) but I am nervous as I might only end up with 20/20 or 20/15 post-op which is not as good as the vision I currently have with my contact lenses.

    I would really value your feedback/opinion on this. I guess I am after a little reassurance, not sure that is possible. One of the main reasons I chose to come to FOCUS was the excellent results reported for 20/20 vision post-op i.e. 100%, I didn’t realise that that might not translate into my vision being as good post-op as pre-op i.e. 20/12.

    My other question is, will my corneas be as strong post-op as they are pre-op or does one end up with weakened corneas and if so, what are the implications?

    Thank you so much.

    Kind regards
    Natasha

    Reply
  2. Minhaj says:
    September 21, 2011 at 12:22 pm

    Hi Dave,

    Thanks for your advice. This will help me choose the right procedure. But of course with an expert consultation. Since you talked about choosing the latest Technology which of the following you consider the latest-

    For Flap Creation

    Visumax® femtosecond laser
    Intralase® femtosecond laser,
    Ziemer’s FEMTO LDV.

    For Corneal Ablation

    The ALLEGRETTO WAVE@ Eye-Q
    VISX STAR S4
    Schwind Amaris 750

    Thanks & Regards,

    Minhaj

    Reply
    • Dave Allamby says:
      September 21, 2011 at 12:48 pm

      hi Minhaj
      For the latest technology for femtosecond flap creation, the Ziemer LDV Crystal Line (newest model) is in my opinion the clear leader.
      For excimer lasers, it depends somewhat on the kind of prescription you have. For short-sight, I would choose the WaveLight Allegretto Eye-Q or either of the Schwind Amaris models, 500 or 750. The Schwind takes away slightly more tissue per diopter, but otherwise the results are the same. If you have a very large amount of astigmatism, the Schwind’s active tracking may be of help. For hyperopia (long-sight), the WaveLight gets the best results, with the Schwind prone to a little more regression in comparison. I personally would not use the VISX for hyperopia treatment.
      Hope that helps. David

      Reply
      • Minhaj says:
        November 30, 2011 at 12:02 pm

        Dear Dave:
        First of all thank you very much for guiding me throughout the process. Your expert advice actually went a long way helping me choose the right procedure. Even though i qualified for both with doctor’s consent I opted for No Touch All Laser Epi-Lasik. I’m quite happy with that.It’s been a little over a month now. Doctor said it’ll take about 3 months for my vision to stabilise. I’m just curious to know a little detail about this procedure. Does it take longer time because the epithelium regrowth takes place like layer by layer (eg. 1 micron at a time) or something else? Why is the recovery time longer?
        Thanks and Regards,
        Minhaj

        Reply
        • Dave Allamby says:
          November 30, 2011 at 2:41 pm

          hi Minhaj, All surface laser techniques improve over 3 months, be it PRK, LASEK, or trans-epithelial PRK. (the term Epi-LASIK is an awful one – just branding to make PRK sound like LASIK). Epithelial regrowth takes about the same time for all techniques, slightly faster for trans-epi PRK as just enough is removed for the treatment zone but no more.
          Best regards, David

          Reply
  3. Minhaj says:
    September 19, 2011 at 11:48 am

    Hi Dave, if I qualify for both Flap lasik & CTEN which one should I go for? To a layman like me it appears since CTEN doesn’t involve any touch and also doesn’t have the flap creation procedure it is safer in the long run.Please correct me if i’m wrong. Is the post operative vision quality any better or similar? There is yet another new technology called Relex or Flex. What is your opinion on that? Thank You.

    Reply
    • Dave Allamby says:
      September 19, 2011 at 5:37 pm

      hi Minhaj, First of all, you can forget about Relex, Flex, and Smile procedures from the Zeiss femtosecond laser, for the time being at least. Having seen the latest results, they do not yet match what can be obtained from advanced excimer LASIK. Interesting concept though, and we will watch where it goes.
      CTEN gives the same results as PRK or LASEK, but just uses the laser to remove the epithelium. You can choose any of these variants, as they will lead to the same outcome. You will want MMC used also if your prescription is moderate to high. I believe the long term safety of femtosecond LASIK and PRK/LASEK/CTEN to be the same, so touch or not doesn’t really matter. If you want a (much) faster recovery and little pain, do choose thin flap femtosecond wavefront (optimised/customised) LASIK. Long-term safety in this respect is about any pre-existing/incipient tendency for the cornea to deform, and this is what corneal topography/mapping is for at your consultation.
      Just choose an excellent centre, surgeon and with the latest technology, and discuss your options with the team.
      Regards, Dave

      Reply
  4. Minhaj says:
    September 7, 2011 at 7:26 pm

    I think C TEN is the same as “No touch all laser EpiLasik”,isn’t it? Eagle Eye Center in Singapore provides it.

    Reply

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