As the number of IOL designs continues to grow, lens implant surgeons have more selections to choose from when deciding on the proper lens for their patients. From aspheric to bifocal and multifocal, and from one-piece to small-incision, IOLs designed for specific indications and treatments continue to flourish on the market.

Several innovative IOLs are featured in this article, that may or may not be in mainstream use today. With their distinct features and unique designs, however, these IOLs may be in regular rotation in the near future. The IOLs included here are just a sample of the many currently available designs. Future issues of Cataract and Refractive Surgery Today Europe will continue to highlight other innovative and cutting-edge IOLs. If you are interested in participating in this feature or know of other IOLs you would like to see featured, please contact our editorial staff.

ACRITEC AcriLISA
The AcriLISA design family (Acritec GmbH, Berlin, Germany) represents a new optical concept, according to the company. The innovative smooth steps of its newly developed optical principle allow it to reduce disturbing light phenomena such as scattered light and halos. The bifocal lens offers reduced glare and improved contrast sensitivity, as well as good near, intermediate and distance vision.

LISA is an acronym for light intensity distribution 65% far and 35% near (L); independent from pupil size (I); smooth refractive/diffractive surface profile (S); and aberration corrected (optimized aspheric optic) (A).

Hakan Kaymak, MD, from the Ophthalmic Clinic, in Sulzbach, Germany, discussed his experience with the lens at the 2005 European Society of Cataract & Refractive Surgeons meeting, in Lisbon. One principle problem with refractive multifocal IOLs, Dr. Kaymak said, is the loss of light. Light is scattered instead of focused between the near and far focus, which results in decreased contrast sensitivity. Additionally, near visual acuity depends on pupil diameter, and dysphotopsia in the form of halos can occur, he said. The novel concepts of the ArciLISA lens may help overcome these problems.

As mentioned above, light is distributed as 65% far and 35% near with this lens; it is independent from pupil size; there are smooth steps in the refractive-diffractive structure; and it is aberration correcting. There is no increase in spherical aberration over the total dioptric range of the lens, Dr. Kaymak said. This is because aberration correction is distributed over the whole eye. Therefore, patients have increased visual acuity and an increased depth of focus.

At the 2006 American Society of Cataract and Refractive Surgery meeting in San Francisco, Dr. Kaymak presented results from 20 patiens who were bilaterally implanted with the AcriLISA lens. Evaluation included UCVA and BCVA for distance and near, defocus curves, contrast senstivity under mesopic and photopic light conditions and patient satisfaction. At the follow-up period of 6 weeks, mean binocular UCVA and BCVA were 1.15 ±0.31 and 1.25 ±0.25 respectively for distance and UCVA 1.04 ±0.31, distance-corrected visual acuity 0.96 ±0.4 for near. The depth of field showed an intermediate VA of 0.6 ±0.21 at 70 cm. Sixteen out of 20 patients reported halos, with no patient experiencing visual disturbances. Only two patients asked for reading glasses. Overall, Dr. Kaymak said, patient satisfaction was high. "The lens showed very good visual performance 6 weeks after bilateral surgery."

Hakan Kaymak, MD, may be reached at CHauck98@aol.com. He states that he has no financial interest in the company or the products mentioned.

VISIOGEN SYNCHRONY
The Synchrony dual-optic accommodating IOL (Visiogen, Irvine, Calif) is a new alternative in the field of cataract and presbyopic surgery, according to the company. The design allows greater accommodation versus single-optic accommodating IOLs and provides good near, intermediate and distance vision.

The lens is silicone and single-piece. The Synchrony has a 5.5-mm high-powered anterior optic connected to a 6.0-mm negative-powered optic by haptics that act like springs, according to the company. The lens comes preloaded in an injector system; it is inserted through a 3.6-mm to 3.8-mm clear-corneal incision.

When the lens is at rest, the optics are separated by a spring action that links the optics, but produces outward force. When the lens is implanted, the capsular bag tension compresses the optics, reducing interoptic tension. According to company, the resting ciliary body maintains zonular tension that is transmitted to the bag, producing circumferential movement of the equator.

Axial shortening of the capsular bag and compression of the lens results in the storage of strain energy in the connecting arms. The lens incorporates stoppers to control minimum separation so that tension may be released on the capsular bag and strain energy stored in the interoptic articulations is released. This function also avoids anterior displacement of the anterior optic.

The posterior optic has a pair of stabilizers that reduce the tendency toward posterior axial excursion, maintaining stability and centration within the capsular bag during the accommodating process.

Burkhard Dick, MD, from the University Eye Hospital Bochum, Germany, has preliminary experience with the lens. In a prospective multicenter trial, Dr. Dick has implanted the lens in 29 eyes. Currently, there are 3-month follow-up results. Dr. Dick said that accommodative lenses (on the whole) are showing significant promise and have certain advantages over multifocal IOLs because they do not have different refractive zones, contrast or glare problems. Thus far, he said, Synchrony in particular has demonstrated benefits over single-optic accommodative IOLs.

More than 300 Synchrony lenses have been implanted thus far, according to Visiogen. The majority have been implanted in Europe and South America. Visiogen began US Food and Drug Administration trials in the fourth quarter of 2005.

The latest clinical results indicate that BCVA of 20/40 or better is achievable in 100% of patients and the distance-corrected near visual acuity of 20/40 or better is achieved in 93% of patients.

The mechanism of action of the optic accommodating IOL has been demonstrated by ultrasound biomicroscopy.

Burkhard Dick, MD, may be reached at burkhard.dick@kk-bochum.de. He did not provide financial disclosure information.

HUMANOPTICS MICROCRYL MC X11 ASP
This lens (Humanoptics, Erlangen, Germany) is a foldable monobloc PCIOL with an aspheric posterior surface. It is made of hydrophilic acrylic with a UV inhibitor and has an estimated A-constant of 118.3. It is recommended for implantation in patients with cataracts, even in those with additional high myopia or hyperopia, to achieve improved functional vision and reduced glare sensitivity.

Why choose an aspheric IOL? According to Humanoptics literature, as the eye ages, there is a loss of ability to compensate for the spherical aberration of the cornea by the lens. Therefore, a positive amount of spherical aberration remains. Instead of one sharp focal point, various widespread focal points arise onto the retina. Spherical aberration thus provokes a reduction of image quality. Conventional IOLs also cause positive spherical aberration, according to Humanoptics literature.

With aspheric IOLs, the regained juvenile balance eliminates spherical aberration, and all light rays are focused exactly on the retina. There is improvement in imaging properties and high-contrast sensitivity.

The MC X11 ASP was developed to give patients the best image quality, expressed by the point spread function. There is higher focal light point density with aspherics; better image quality and a point spread function closer to 1. According to Humanoptics literature, spherical IOLs do not even reach point spread function values of 0.1.

The lens has a sharp edge design, according to the company. It can be implanted through a small incision (sub-2.5- mm) with the Medicel Viscoject Injector and 2.2 cartridge set (both by Humanoptics). The lens is easy to fold, safe to implant and there is less glare in the case of larger pupils. An added advantage is its >6-mm diameter, which is suitable for surgeons in case of potential interventions in the ocular fundus.

"We are currently comparing the spherical IOL versus the aspheric in a prospective randomized study, enrolling more than 100 patients," said Christoph Winkler von Mohrenfels, MD, from the University Eye Clinic Munich rechts der Isar, in an e-mail to Cataract & Refractive Surgery Today Europe.

"Our first impressions on the same design and shape of the microincision lens, but with different surfaces (first group, spherical and second group, aspherical) are that we can see significant enhancement [and benefit] on contrast sensitivity. Early analysis that we have to observe in following postoperative assessments indicate that the contralateral eye operated with the aspheric lens MC X11 ASP gives the majority of patients advantages in daily dimmed light conditions such as driving by night and general mesopic light conditions."

Christoph Winkler von Mohrenfels may be reached at christoph.wvm@web.de. He states that that he has no financial interest in the company or products mentioned.

OPHTEC ARTIFLEX AC 401
The unique features of the Artiflex lens (Ophtec, Groningen, Netherlands), which is the latest evolution of the Artisan IOL, include its iris-fixated claw, antiglare edge, controlled folding and unfolding, large optical zone and lateral sideports. The Artisan lens concept has been in use since 1978 and was designed by surgeon and inventor Jan Worst, MD. It has the longest history of any surgically implanted phakic IOL.

The Artiflex received Conformitié Européenne (CE) approval in September 2005 and is currently being introduced worldwide. The IOL can be implanted through a minimally invasive microincision, according to the company.

According to Erik-Jan Worst, CEO and president of Ophtec: "Surgeons who were involved in the European clinical study were amazed by the clinical results and quick visual recovery [with the lens]. We were impressed with the very high level of interest during the introduction at the ESCRS meeting in Lisbon, where training courses were standing room only."

In clinical studies of 350 eyes, the lens produced excellent visual acuity results and high predictability. It was safe in terms of complications, and the results were stable.

"Phakic IOLs have been used in refractive surgery for the last 18 years," according to António A. P. Marinho, MD, PhD, from Porto, Portugal. "Although the different models had a great success in refractive terms, with accuracy and predictability far superior to refractive corneal surgery, they have been associated with important complications. Angle-supported anterior chamber phakic IOLs were dangerous to the corneal endothelium in the first models. Even the present ones, although safe for the endothelium, are still associated with some rate of pupil distortion due to the inaccuracy of IOL size calculations. On the other hand, posterior chamber phakic IOLs have been associated with cataract formation and in some models with zonular damage and vitreous migration," he said in an e-mail to CRSToday Europe.

"Iris-supported phakic IOLs, such as Ophtec's Artisan/Verisyse, being independent of the eye size (one size fits all) and being at a safe distance from the corneal endothelium and the natural lens, are almost devoid of complications if the surgery is gently performed," he continued. "Being made of PMMA and having a diameter of 5 mm or 6 mm, a large incision must be made, creating the need for sutures, with the possibility of inducing unwanted astigmatism and slowing visual rehabilitation.

"But this new phakic IOL, the Artiflex, is a foldable iris-supported phakic IOL, combining the proven advantages of the Artisan model with the small incision. We have implanted [the lens in] 81 eyes (40 patients) with myopia from -3.00 D to -15.00 D and with or without astigmatism (≤2.00)."

Patients ranged in age from 19 years to 50 years. Follow-up occurred from 3 months to 2 years.

"Concerning the accuracy, 88.5% of the eyes were between -0.50 D and +0.50 D. The other 11.5% were between -1.00 D and +1.00 D. No change was observed in astigmatism. No eye lost any line of BCVA, and 50% of the eyes showed improvement in BCVA (one to two lines)," Dr. Marinho said. "Endothelial cell counts did not show cell loss. Patient satisfaction was very high, and the patients recovered their BCVA within hours after the surgery (even quicker and with less pain than with LASIK).

"No important complications were observed, although in heavily pigmented eyes, we had four cases of pigment and giant cell deposits on the IOL. In two of these eyes, there was a transient loss of two lines of BCVA. Treatment with topical and oral steroids led to full recovery. Since we give prophylactic oral steroids, no case of deposits has been seen.

"This new phakic IOL seems to be the safest phakic IOL in the market as it combines the proven safety and efficacy of the Artisan/Verisyse with the known advantages of the small sutureless incision," Dr. Marinho concluded.

António A. P. Marinho, MD, may be reached at marin@mail.telepac.pt. He states that he has no financial interest in the company or products mentioned.

TECHNOMED EASYCARE 600
The Easycare 600 IOL (Technomed, Baesweiler, Germany) incorporates a labeling system that displays the exact refraction value of the IOLs. According to the company, 0.50-D increments are not enough, because accuracy has continuously improved over the last several years through items like optical biometry and new formulas. As the expectations of both surgeons and patients have continually risen, it is more important to make outcomes as accurate as possible. To this end, Technomed developed its exact refraction labeling system.

According to Axel von Wallfeld, vice president of Technomed, the second largest error surgeons make when calculating the end refraction of a patient relates to the IOL. The first largest errors are measurement mistakes. The International Organization for Standardization (ISO; that all IOL manufacturers adhere to) allows for a ±0.30-D variation from the labeling on lenses from 0.00 D to 15.00 D and ±0.40-D variation on IOLs from 15.00 D to 25.00 D and even more in higher-diopter lenses. Above 30.00 D, tolerances of ±1.00 D are allowed.

In a worst-case example, a patient may measure 21.31 D. The surgeon chooses a 21.50-D lens, but that lens may really be 21.90 D. This results in 0.60-D variation from the lens alone, and other factors may add up.

Technomed measures each of their lenses to within 0.10 D, so the labels include both the common 0.50-D step labeling and the exact refraction values. The company believes that this step will minimize postoperative refractive errors associated with mismatched lens power and increase the accuracy of surgical results.

The IOL is a three-piece cataract lens designed to be implanted in the capsular bag, but it can also be implanted into the sulcus. It has a 6-mm optic, a sharp rear edge and a rounded front edge to avoid glare and halo. The haptic design of the hydrophilic acrylic lens has been adapted to create a stable refraction after implant. The long C-loop fits into the bag and stays in place.

"A labeling system that displays exact refraction values on IOL packages, rather than 0.50-D step values, has been developed to attempt to enhance the postoperative refractive outcome of cataract surgery," said Markus Kohlhaas, MD, in an e-mail to CRSToday Europe.

"Technomed has begun using the exact labelling on its EasyCare 600 IOL and is offering ophthalmologists the option to order whatever lens power they need. With standard package labelling, surgeons assumed that the power of the IOL in the package was within ±0.25 D of the labeled dioptric power, when in fact, the manufacturing tolerances set out by ISO are much broader," said Professor Kolhaas, from St. Johannes-Hospital, Dortmund, Germany.

"The Easycare IOL is the ideal lens for refractive lens exchange patients with high and even very high hyperopia where precision is important."

Markus Kolhaas, MD, may be reached at Markus.Kohlhaas@joho-dortmund.de. He states that he has no financial interest in the company or the product mentioned.

CORNEAL ICARE refractive anterior chamber iol
Corneal's (Paris) Icare lens is the first injectable refractive anterior chamber lens, according to the company. The lens has an innovative design that fits perfectly with the ocular anatomy. Due to its shape, it avoids contact with the cornea, thereby preventing alteration of corneal tissues, according to information on Corneal's Web site.

The injectable IOL is introduced into the eye via a small incision, ensuring optimal visual recovery and absence of induced astigmatism as typically, no sutures are required.

Pupil deformities, ending in oval distortion, are complications specific to anterior chamber lenses. Their occurrence immediately after surgery is linked to an inappropriate IOL diameter. For this reason, according to Corneal, the Icare refractive lens is available in four different diameters, allowing adaptation to all the various anterior chamber diameters.

In an e-mail interview with CRSToday Europe, Michael Assouline, MD, PhD, described his experience with the lens. "The Icare injectable phakic lens designed and manufactured by Corneal is my current best choice for the correction of myopia from -5.00 D to -20.00 D in patients that are not eligible for either UltraLASIK (ie, femtosecond LASIK with wavefront and iris recognition guided ablation) or cataract surgery. I have been using this lens for 5 years and I have found that, besides its simplicity, this lens provides an optimal quality of vision and a most acurate correction.

"Because it is injectable using a standard cartridge, there is no learning curve, as opposed to difficulties encountered even by experienced surgeons with iris fixated lenses (look for live surgery sessions). The small-incision size of 3 mm helps control the correction of astigmatism. No peripheral iridectomy is required. The hydophillic acrylic used is very gentle to the intraocular structures during the surgery and superbly tolerated in the long term within the anterior chamber (no pigment dipsersion or deposits, no giant cells, no low-grade inflammation). The hydophilic material also helps minimize unwanted glare and dysphotopsia reported with higher refractive index materials. Induced spherical aberration is minimal.

"The unique design of the lens, with four mechanically independent haptics can absorb a good part, if not all of, the residual sizing error that has plagued the outcome of previous angle supported phakic IOLs.

It seems, however, essential to keep measuring the implantation site (scleral spur to scleral spur distance) using the best available method (ie, 20-MHz B-mode) ultrasound scan or high-resolution anterior segment optical coherence topography, to avoid oversizing and excessive vaulting, or undersizing and rotation. As for any ACIOL, special attention should be paid to anatomical changes of the angle associated with aging in patients >50 years. A trimmed version of this lens called the Icare Evolution, with less vaulting, was recently made available by Corneal, for patients with smaller anterior chamber.

Michael Assouline, MD, PhD, practices at the Clinique de La Vision, in Paris. Dr. Assouline is a member of the CRSToday Europe Editorial board, and states that he is a paid consultant for Corneal, is an unpaid consultant for Bausch & Lomb and has no relationship with Intralase. He may be reached at assouline.mauritius@wanadoo.fr.