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Small-aperture IOL may be effective approach to presbyopia in cataract patients
Good vision is achieved at all distances, with no issues regarding adaptation and photic phenomena.
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The small-aperture AcuFocus IC-8 IOL is a new concept in presbyopia correction, combining the advantages of IOL technology with the pinhole camera effect of the Kamra inlay.
“It is a technology that should work in the market nicely and is raising the interest of several companies,” Günther Grabner, MD, OSN Europe Edition Board Member, told Ocular Surgery News.
The IC-8 is a one-piece hydrophobic acrylic lens with an embedded opaque annular mask and a central aperture. This design is aimed at providing vision at all distances and has so far been used for implantation in one eye.
“One advantage is that it can be used in one eye only in cataract patients previously implanted with a monofocal IOL in the other eye if they want to gain some depth of focus for reading distance,” Grabner said. “You do the second cataract eye and target it for –0.5 D to –0.75 D. The patient will have good distance vision, in the range of 20/25 to 20/20, plus the benefit of an added near focus.”
Other presbyopia-correcting IOLs, including multifocal refractive and diffractive and to some extent the newest trifocal technology, sacrifice some distance vision to correct near and induce a variable amount of glare and halos.
“This lens works by the small-aperture principle, with no consequences in terms of glare and halos. My grandmother died at the age of 94 and never used glasses because she had a very narrow pupil. She had a good distance vision and could read without any spectacle aid in good lighting conditions. It is basically the same principle,” Grabner said.
Lens vs. corneal inlay
The IC-8 IOL is less demanding in terms of patient selection and implantation than the Kamra inlay, which Grabner has used for several years.
“The Kamra needs a good corneal or refractive surgeon and a good laser. I have more than 10 years of experience with it, and over this time the implant has improved significantly. It is now 5 µm thick, has a special distribution of the nutritional holes, and we know now that implanting it into a deep pocket makes a major difference as compared to the initial technique of inserting it under a flap. However, to make it work you need a good laser to perform a good, deep pocket with small line-spot spacing. You need careful surgery and a nice centration,” he said.
After 10 years, he is still happy with the results, which are not perfect but good enough for patients who are not too demanding.
The results of the IC-8 IOL are better and more easily achieved, he said. Surgery is routine cataract surgery, with a good, well-centered capsulorrhexis.
“Basically, all cataract surgeons can easily use this implant. It is standard phaco surgery. Your cataract patients will be grateful for the added benefit of an increased depth of focus with no problems of adaptation or visual disturbances. The important thing is to aim at a minus target and do precise biometry — either with the IOLMaster (Carl Zeiss Meditec) or with the Lenstar (Haag-Streit) or similar systems that you are used to in order to gain maximum benefit for the patient. It might also be helpful to use a femtosecond laser, if you have access to one,” Grabner said.
Good results
Grabner started using the lens at the beginning of 2012. At that time, the implant was made of silicone, and he used it in a dozen cases. Data were not presented because the lens was not approved. One year later a new model was released, made of foldable acrylic and designed for a smaller incision.
“I did again a dozen patients, in cooperation with Bobby Ang from the Philippines, and the data were submitted and accepted for publication in a peer-reviewed journal. I am happy with the outcomes, though there are still some modifications that the lens needs,” Grabner said.
Patients should be told that they might need reading glasses for very small print or for when they are reading a long text or are tired. However, on average there is no need for glasses to read the newspaper, and medium distance is good.
“The range of computer distance is very well targeted by this lens. At 60 cm to 80 cm, patients do very well, and this is important nowadays,” Grabner said.
Grabner said he prefers using the femtosecond laser to perform the procedure because this ensures a good capsulorrhexis. He would not implant the lens if the capsulorrhexis is not perfectly centered or if it has breaks.
There is no problem in visualizing the back of the eye with the IOL in place.
“You can perform OCT. You can laser the retina and look at the periphery if there are retinal breaks, look at the optic nerve. You need a well-dilated pupil and some experience; it may be a little trickier but certainly not a problem for experienced surgeons,” Grabner said.
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- Günther Grabner, MD, is professor at Paracelsus Medical University and former director of the University Eye Clinic in Salzburg, Austria. He can be reached at Dr. Franz Rehrl-Platz 2, 5020 Salzburg, Austria; email: g.grabner@grabner-augen.at.
Disclosure: Grabner reports no relevant financial disclosures.