Video Interview: The KAMRA Presbyopia Inlay

Dr. Goldman interviews George Waring IV about the KAMRA presbyopia inlay. Working on the presence of a small aperture, this pinhole effect allows a greater depth of focus. Building on previous generations of corneal inlays, the KAMRA inlay is developed with thousands of pores to allow adequate nutrition and hydration of the cornea. By being placed under a corneal flap or pocket, it has not shown to have any late onset decentration. Removal, if required, has not resulted in any loss of best corrected visual acuity.

Video Interview: The KAMRA Presbyopia Inlay

Dr. David Goldman Interview with Dr. George Waring

Dr. David Goldman:  Hi, I'm David Goldman, Refractive Editor for, speaking today with Dr. George Waring, a cornea, cataract and refractive specialist out of Columbus, Ohio.  Thank you so much for speaking with us today.

Dr. George Waring:  Thanks, Dave.  It's great to be here.

Dr. David Goldman:  You know, one of the things that you do a lot of work with that I think is a very exciting technology is the KAMRA inlay, and I was hoping we could talk a little about that today.

Dr. George Waring:  Yeah, that'd be great.

The KAMRA inlay, it's an inlay to treat presbyopia; it's a presbyopic inlay.  And the--there's a number of reasons why it's really promising.  It's a--works on the principle of a small aperture, so it's a--like, a pinhole, so this is small aperture keratophakia.

You know, the idea of using corneal inlays goes back, you know, 50 years, and there's been a lot of research and development and improvements over time that would allow the stroma to accept an inlay, and it's really exciting to actually see that occur.

The neat thing about the KAMRA inlay is that it is, number one, removable if the patient elects to have it out.  And, you know, having now over 1,100 patients enrolled in clinical trials, we have a good idea about safety and efficacy.  For the few people that have elected to have it removed, the patients have lost no lines of best corrected acuity and returned back to normal, so that's reassuring for not only the surgeon, but, of course, for the patient.

Dr. David Goldman:  Sure.

And obviously, there's been a history of intracorneal inlays, but what are some of the modifications that were made to this inlay to make it acceptable to the corneal stroma?

Dr. George Waring:  Yeah, a number of things, not only with the inlay, but also with how the inlay is implanted.

The inlay has 8,400 nutrition holes that allow for the appropriate metabolic pathway, as well as not only metabolites, but catabolites as well, and also allows for the appropriate hydration pathway, too.  So, these are all important for a good, reliable outcome and to allow this prosthetic device to be accepted in the intracorneal space.

Dr. David Goldman:  And how are you implanting it into the cornea?

Dr. George Waring:  You have two options.  You can either implant it into a pocket, which is very exciting; it's a really neat breakthrough from the standpoint of biomechanics and preventing post-op temporary dry eye.  Now, that--you're somewhat limited if you are treating plano presbyopes or near plano presbyopes.  Particularly for low degrees of myopia, this can be very useful.  We've found that the pockets become very useful for other indications, such as post laser vision correction and things like this.

Now, what's really exciting and what's really taken off with the commercial launch outside of the US is the simultaneous implantation with LASIK, so you can imagine how that broadens this indication.  You've got--basically, you can simultaneously treat myopia, hyperopia and astigmatism and presbyopia at the same time.  So, it's been very, very successful, and the patients have done quite well.

The thing that makes this inlay unique is that it does very well in the face of the progressive nature of presbyopia, and that's pretty--that's unique for a corneal presbyopic procedure.  I mean, we know that for monovision, you're setting a set target, and you're going to outgrow that depending on how much myopia you induce, even with PresbyLASIK or some of the other multifocal corneal techniques.  Although some depth of focus is increased, this is still really a fixed point more or less.  And the inlay, because of the small aperture, does not show any deterioration, and that's really, really--it's a--it's been one of the things I've been most impressed with, with this technology is that you've got stability out five years with--while you know the patient's becoming increasingly presbyopic.

Dr. David Goldman:  And I think it's important to note, too, that this is something that just is performed in one eye, the non-dominant eye.  It's not something that even has to be done for both eyes to achieve the outcomes that you're getting.

Dr. George Waring:  That's true.  Actually, it really should only be done in one eye, and the patient does well. 

And, you know, dominance is a very interesting thing to consider.  We've learned all kinds of neat things with this technology, whether it's centration, assessing dominance.  We've learned that you don't only want to put it in the non-dominant eye, but there's a population that actually would prefer to have it in the dominant eye depending on their daily activities. 

So, you know, we've learned a lot.  But, you're right, it is a monocular procedure, but it's not monovision.  That's really critical to understand.  This is--patients are seeing--our data has shown us in the US IDE study with over 500 patients, and we've got 18-month data now--this is sort of hot off the press--that we've got basically at 18 months J1 or J2 and 20/20 in the implanted eye only.

Dr. David Goldman:  Hmm.

Dr. George Waring:  And so, this is not monovision, though it is a monocular procedure.

Dr. David Goldman:  And you mentioned centration.  Have there been any issues--I know in past models there have been issues regarding migration of the inlay.  Has there been any issues with the KAMRA inlay?

Dr. George Waring:  It's a good question, and it's a commonly asked question.  Actually, migration was never really an issue with the KAMRA.  Just the nature of the material and how it adheres to the stroma, it's actually--it actually does not move.  And so, when you're implanting it, you actually float it just a little bit to get it to move into the right position.  So, it's absolutely not an issue.

Centration, however, is a big deal, and we've learned a lot about this.  AcuFocus, in conjunction with SMI, have developed a centration device called the AcuTarget that's very sophisticated, but very easy to use, that allows you to measure and determine preoperatively where you're going to place the inlay on the estimated line of sight. 

And you can actually--they're now developing an intraoperative guidance tool that you can export that data, put it in--it's a real-time overlay in a surgical microscope that's projected on the ocular surface and moves with the movement of the cornea.  It tells you exactly where to place it.  As importantly, for post-op evaluation, if the patient is not doing as well as you'd like, then you can re-measure and see how far off were you from your intended placement.

Dr. David Goldman:  Well, it sounds like a fantastic technology.  Any idea when we'll be able to use it in the US?

Dr. George Waring:  Well, we're hoping for first quarter of 2012, but--and I'll tell you, it's--I'm really excited to see that come through the FDA process.  So, we've gotten optimistic because we've exceeded all safety and efficacy standpoints.

Dr. David Goldman:  Well, it sounds like an excellent technology.  We can't wait to get our hands on it.

Dr. George Waring:  Yeah, I'm excited, too.

Dr. David Goldman:  Well, thank you so much for joining us today.

Dr. George Waring:  Thanks, Dave.  Thanks very much for having me.

Dr. David Goldman:  For more information, please click on the links below.


AcuFocus KAMRA™ Inlay, Revolutionary Presbyopia Correction Technology, Exceeds 5,000 Implants Globally