see here: cataractcoach.com/?s=eyhance
for the full article and figures which will be live on August 1, 2021
I am thankful to the engineers who continually improve our surgical products through technical advances. These engineers are usually smarter than the doctors (definitely smarter than me) and they give their best effort to push the envelope of what is possible. I always welcome new technology and innovations for cataract surgery because they allow us to offer our patients more options to deliver the desired visual results. As ophthalmologists, we must also separate the marketing and the push from the sales representatives from the actual optics and the science. We never want to be in the position where patients believe that a magical outcome is possible and that we can mysteriously cheat physics. Let's be straight here: we cannot cheat physics and there is no free lunch when it comes to optics!
Today we are talking about the new (for USA) Johnson & Johnson (J&J) Tecnis Eyhance IOL for cataract surgery, models are Tecnis DIB00 for pre-loaded or ICB00 for the stand-alone IOL. This is a new monofocal IOL which is built on the previous Tecnis ZCB00 platform (ZCBOO is colloquial speak) and, in my opinion, is an incremental improvement to that lens. In this press release from J&J Vision, the Eyhance is clearly labeled as a monofocal IOL "designed to slightly extended depth of focus" -- the key word there is slightly. The Eyhance is not classified as a presbyopia-correcting extended depth of focus (EDOF) lens implant.
This article and video are entirely my personal opinion and figures are presented under the fair use educational review criteria. I do not have any disclosures or financial relationships to J&J (many years ago when the Tecnis platform was part of AMO: Advanced Medical Optics, I was a paid consultant to them). The Tecnis Eyhance comes with Directions For Use (DFU) which you can find at the manufacturer's website here.
www.jnjvisionpro.com/sites/us...
Should you click on the link and go through the DFU? Reading the DFU is not optional for surgeons, but rather it is required -- at least in my view. While the patient has done "Google homework" and the sales rep has given her/his pitch, the bottom line will be found in the DFU. Note that there was NO separate FDA study done for the Tecnis Eyhance DIB00 / ICB00. In an email to a J&J representative I learned that, "There was no FDA study for the Eyhance as it was a level A modification that did not require clinical data." Got it -- an incremental improvement and not a revolutionary change. Let's keep that in mind and temper our expectations.
This DFU reveals that the incremental change in the Tecnis monofocal (ZCB00 or ZCBOO) is a central 1 mm diameter zone of the aspheric anterior surface that creates a small continuous increase in central lens power. This is shown in the picture above which is from J&J and is presented here under the fair use for educational review (this is important in the USA when we use materials from others).
In the DFU for the Tecnis Eyhance DIB00 & ICB00 (colloquially called Tecnis Eyhance DIBOO and Tecnis Eyhance ICBOO) it clearly states that "clinically meaningful extension of depth of focus has not been demonstrated in clinical trials" (boldface/italics of the 'not' is by me, but the official text definitely says "not"). It goes on to state that "in general, extended the depth of focus negatively affects the quality of vision at far distances," which correlates well to our knowledge that you cannot cheat the physics of optics.
I think that the Tecnis Eyhance is a good incremental upgrade over the standard Tecnis ZCB00 (ZCBOO in colloquial terms) and that it is a really good monofocal IOL. It is NOT an extended depth of focus IOL like the J&J Tecnis Symfony (diffractive technology) or the Alcon AcrySof Vivity (beam-shaping technology), and patients should absolutely NOT expect to get an extended depth of field sufficient for reading vision (20 inches or closer) with this lens.
As you can see, there is no free lunch when it comes to the physics of optics. The total number of photons that enters the eye is going to be the same, but we can change how we distribute this light energy. In this MTF graph we can see that light energy is taken away from the red zone and then added to the green zone in order to increase the depth of focus by a slight amount. This is NOT an extended depth of focus lens and unless you have really, really long arms (1 meter), it will NOT give reasonable reading vision without glasses.
.... ran out of room here on KZfaq, so please go here to read it all and see the pictures / diagrams:
cataractcoach.com/?s=eyhance