Add-on IOL an option for surgery for correcting ametropia in pseudophakic eyes

Multifocal model offers near emmetropic patients with low astigmatism a chance for spectacle independence after implantation, surgeon says.

A new add-on IOL is a viable alternative to surgical intervention for correcting unstable ametropia in pseudophakic eyes, according to a surgeon.

Detlef Holland, MD, and colleagues in Germany implanted 22 Add-On IOLs (HumanOptics) in 16 patients with residual ametropia after previous cataract surgery.

The IOL is available in toric, spherical and multifocal diffractive models. “For us, the most interesting thing with this technology is the multifocal Add-On,” Dr. Holland said in an interview with Ocular Surgery News. “For patients who are near emmetropic with low astigmatism, it is an opportunity to get spectacle independence after implantation.”

The lens measures 14 mm in diameter with a 7-mm optical zone. It has a concave design of the posterior surface of the optic to avoid contact with the previously implanted lens in the capsular bag and is designed for implantation into the ciliary sulcus through a 3-mm incision.

“We had no intraoperative or postoperative complications. The intraocular pressure was in the normal range, all the IOLs were centered, and no iris capture or depigmentation occurred,” Dr. Holland said at a presentation of his first clinical experience with the new technology at the European Society of Cataract and Refractive Surgeons meeting. In addition, he said, all patients in the study achieved Nieden 1 near vision.

Rotational stability

Although he expressed confidence in the new lens, Dr. Holland also warned that rotational stability was an issue, particularly with the toric model without undulated haptics. “The company that produces these IOLs has already changed the haptic, but we have not performed any add-on IOL procedures with this IOL with the new haptic. We have no impression what it will be like,” Dr. Holland said.

In a statement e-mailed to OSN, HumanOptics CEO Karl Klamann said, “After many years of experience with toric IOLs featuring undulated PMMA haptics to avoid postop rotations, some key surgeons suggested that placing the Add-On IOL into the sulcus of a pseudophakic patient would simply require standard haptics only. The idea was that there would be no such biomechanics in the sulcus as known from capsular bag shrinkage. However, we can see from the follow-up that other biodynamic factors applying to a sulcus fixated Add-On IOL. Hence, undulated haptics, which are significantly increasing the resistance toward rotation, are necessary. In fact, the toric Add-On IOL featuring undulated haptics have shown perfect rotational stability in clinical studies carried out in three other European sites recently.”

Requirements for implantation

In the initial case series, Dr. Holland and his team implanted the Add-On IOL during cataract surgery, but now he only performs the procedure in patients with a previous IOL implantation with unstable ametropia and stable refraction, he said.

“There is one indication where we would do it as a single procedure,” Dr. Holland said. “If you have a patient with a very high astigmatism, then there is a demand for a multifocal IOL. At the moment, there are not a lot of torical, multifocal IOL on the market. In this case, we would implant a toric IOL in the capsular bag, and then in the same procedure, the multifocal IOL in the sulcus.” – by Bryan Bechtel

Being a “historical” advocate of piggyback lenses, I like the Add-On concept, and I am planning to use some of these lenses in the near future for secondary multifocality. Based on the preliminary results of this study, they seem to deliver a safe platform for piggyback enhancement.

The toric experience is not so good, but I would not want to use them for that purpose; limbal relaxing incisions or excimer laser enhancement work pretty well in this regard. If these lenses keep their promise and are optically sound as well as being safe and easy to implant, then they will open up a whole new group of patients for surgery – those that were already pseudophakic but wish to become spectacle independent. We need greater numbers and a longer follow-up, but I believe this to be a very positive step.

— Richard B. Packard, MD
OSN Europe/Asia-Pacific Edition Board Member

Detlef Holland, MD, can be reached at the Eye Hospital Bellevue, Lindenallee 21, 24105 Kiel, Germany; +49-431-301080; e-mail: d.holland@augenklinik-bellevue.de.