August 2018

CATARACT

Presentation spotlight
Reversible and adjustable lens solutions


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer

Supplementary IOLs are effective for secondary enhancements and for primary duet implantations


Multifocal toric additive IOL in mydriasis

Slit lamp photo with IOL surface reflexes
Source: Michael Amon, MD

Biometrical surprises after cataract and refractive surgery are unwelcome and need to be dealt with promptly. The best approaches involve uncomplicated surgery, such as those offered by secondary, supplementary IOLs, designed to provide simple, adjustable solutions.
Presenting an overview on supplementary IOLs for the pseudophakic eye at the 22nd ESCRS Winter Meeting, Michael Amon, MD, Academic Teaching Hospital of St. John, and Sigmund Freud Private University, Vienna, Austria, explained that the success of secondary IOL implantations was a result of the progress made on many different levels.
“One of the problems encountered in early supplementary IOL implantations in the 1990s was that the lenses were implanted together with the primary lens into the capsular bag. As we all know, the proliferative cells from the equator invaded the interface, and the lenses needed to be explanted,” Dr. Amon said. “The second problem was the use of two biconvex lenses, which resulted in a central contact that
led to a flattening of the contact zone and a resultant hyperopic
defocus. The third problem was if we put a lens into the sulcus, there could be iris chafing (pigment dispersion), inflammation, raised IOP, or hemorrhage.”

New technologies

Current lens designs for use as secondary implants incorporate targeted improvements drawn from the lessons learned over time. Secondary lens designs are hydrophilic acrylic, single-piece IOLs. Hydrophilic acrylic material has a high uveal biocompatibility, which is important due to the direct contact between the device and the uvea.
There are three supplementary lenses available, the Reverso (Cristalens, Lannion, France), the Sulcoflex (Rayner, West Sussex, U.K.), and the 1stQ (1stQ GmbH, Mannheim, Germany), that share basic characteristics. They have relatively large optics of between 6 and 6.5 mm in diameter, which overlap the primary lens to avoid iris/optic capture; they are round-edged devices, resulting in less dysphotopsia and less posterior capsule opacification (PCO); they have a concave posterior surface to avoid hyperopic defocus at the contact zone; they have long haptics, 13.5–14 mm diameter for good centration and rotational stability; and they are angulated to ensure uveal clearance.
“I mostly implant aspherical monofocal supplementary lenses to correct biometric surprises,” Dr. Amon said. “But all options are available, multifocals, both refractive and diffractive; torics, as a supplementary toric correction, like for post-PKP patents where we have a dynamic change of the axis; and multifocal toric lenses.”
Other supplementary lenses include the Black Pinhole IOL (Morcher, Stuttgart, Germany), an extended depth of focus IOL using a stenopeic hole, which offers a feasible option in eyes with irregular astigmatism that standard lenses cannot address; and the iolAMD Eyemax (iolAMD, London, U.K.), which uses a hyperaspheric optic to magnify 1.3x and is useful in AMD patients who greatly benefit from the extra magnification.

Why use a secondary sulcus fixated IOL?

The key benefit of supplementary lenses is their reversibility. Supplementary lenses represent an adjustable and exchangeable choice as primary add-ons. They also offer a reversible alternative to laser enhancements and the option to avoid IOL exchange in cases of a post-surgical refractive surprise or astigmatism correction.
One example of when secondary lenses can benefit a situation is when choosing a multifocal solution. Multifocals may not be for everyone, and despite informed decision making, it is prudent to allow for change if patients become dissatisfied somewhere down the line. In a study that evaluated diffractive multifocal IOLs as part of dual surgery with monofocal capsular bag IOL implantation, there was high safety and efficacy for the combined procedure, with preliminary visual acuity results similar to those obtained in eyes with single-piece diffractive multifocal IOLs.1 Add-on patients had the option to reverse or adjust their treatment.
Dr. Amon said, “Indications for primary implantation, also called duet implantation, where both lenses are implanted in the same stage, are high ametropia, for instance when you don’t have the lens in stock for the high correction and can add the missing power through the second lens; high astigmatism; a multifocal duet procedure, which for me is one of the main options and benefits from these lenses because you have reversibility if the patient is incompatible with the lens; and deconversion. More importantly, if the patient within the next decades develops AMD or diabetic macular edema, you can explant the supplementary lens at any time. Uses as a secondary implant include spherical correction because of biometrical surprises, astigmatic correction, conversion from monofocal to multifocal, dysphotopsia, magnification, and stenopeic hole. It is a big advantage to be able to step back and reverse it.”
A prospective non-randomized study that Dr. Amon co-investigated showed that the implantation of the Sulcoflex 653L (Rayner) secondary IOLs in the ciliary sulcus to correct residual refractive error after phaco with in-the-bag IOL implantation in 12 eyes of 10 patients was safe, predictable, and well-tolerated.2 None of the study eyes showed pigment dispersion, interlenticular opacification, optic capture, or pupil ovalization. In a separate study that reviewed the charts of 46 secondary IOL patients in which one surgeon performed surgery in one practice, study investigators concluded that supplementary IOLs were a viable surgical option to correct residual refractive error after primary IOL implantation, including 10 cases involving secondary toric IOLs.3 In the study, rotation did not exceed 10% in eyes with toric secondary lenses.

Practical and easy

The IOL calculation for secondary implantations in cases of biometrical surprise is straightforward. In cases of ametropia between ±7 D, the surgeons multiplies the spherical equivalent by 1.5 in hyperopic cases and by 1.2 in myopic cases. Dr. Amon usually uses a 2.4 mm incision. He injects viscoelastic, folds the device into the injector or uses forceps, and positions the IOL into the ciliary sulcus. He performs aspiration of OVD from the interface to avoid a secondary pressure increase, places an iridotomy in children, short, or odd eyes, and applies an antibiotic. When part of a duet procedure, he removes the viscoelastic from the bag from the first procedure, then adds viscoelastic behind the iris and continues as above, placing the secondary lens behind the iris.
Dr. Amon suggested placing a suture for toric add-ons, as a 10% rotation would change refraction by 30%. However, the centration of monofocal sulcus fixated supplementary IOLs was significantly better than bag fixated IOLs when compared to the limbus and with the dilated pupil, according to a study that he co-authored that looked at centration of sulcus fixated supplementary IOLs implanted anteriorly to preexisting capsular bag IOLs in 48 eyes of 43 patients.4 He explained that lenses implanted in the sulcus do not experience shrinkage, capsular contraction, or any form of change, like IOLs implanted in the capsular bag might.
“Children present a challenge because their eyes grow and the lens power has to be adapted. That is where the reversibility comes in that I like so much in this lens system. You can remove the lens when you need to and exchange it at any time, for instance when eyeball growth creates a myopic shift,” he said. “The explantation works easily. You do not have to cut the lens or fold it within the eye. You just grasp it and pull it out through the incision.”

References

1. Gerten G, et al. Dual intraocular lens implantation: Monofocal lens in the bag and additional diffractive multifocal lens in the sulcus. J Cataract Refract Surg. 2009;35:2136–43.
2. Kahraman G, Amon M. New supplementary intraocular lens for refractive enhancement in pseudophakic patients. J Cataract Refract Surg. 2010;36:1090–4.
3. Gunderson KG, Potvin R. A review of results after implantation of a secondary intraocular lens to correct residual refractive error after cataract surgery. Clin Ophthalmol. 2017;11:1791–1796.
4. Prager F, et al. Capsular bag-fixated and ciliary sulcus-fixated intraocular lens centration after supplementary intraocular lens implantation in the same eye. J Cataract Refract Surg. 2017;43:643–647.

Editors’ note: Dr. Amon has financial interests with Alcon (Fort Worth, Texas), Bausch + Lomb (Bridgewater, New Jersey), Johnson & Johnson Vision (Santa Ana, California), Carl Zeiss Meditec (Jena, Germany), Morcher, and Rayner.

Contact information

Amon: michael.amon@med.sfu.ac.at

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