New IOL choices can satisfy patients, bring referrals

John A. Hovanesian

Paul M. Karpecki

Presbyopia correcting IOLs have become one of the most exciting developments in eye care, and demand from patients is expected to rise sharply in the coming years as more patients become aware of a lens upgrade option through their peers and direct-to-consumer advertising that is already appearing in large media markets. Clinicians who are familiar with these technologies and can educate their patients about strengths and limitations will be rewarded with highly satisfied patients who refer friends and relatives for treatment.

Over the past 5 years in each of our practices we have comanaged thousands of patients undergoing refractive cataract surgery using virtually all the available modern, premium IOLs. Through this experience we have learned a number of important lessons in working with patients before, during and after surgery.

In this first article, we will focus on the four categories of premium lens implants available in the United States and discuss when they are best used.

Monofocal aspherics

Monofocal aspheric lenses include Abbott’s Tecnis and Clariflex, Bausch + Lomb’s Softport AO and Akreos AO, Alcon’s Acrysof IQ and Hoya’s iSert. Designed to minimize higher-order aberrations, these IOLs generally do not involve out-of-pocket charges to patients. They are not able to correct astigmatism or presbyopia, however.

Multifocal choices include the Alcon ReStor (left) and the AMO ReZoom (center), and Bausch + Lomb’s Crystalens offers accommodation. Image: Hovanesian JA

Surgery centers providing these lenses may be eligible for extra reimbursement from Medicare for these more costly lenses, but these “advanced technology IOL fees” are not generally shared through comanagement because the new technology fees are paid to the surgery center simply to offset the increased cost of the IOL supply.

These lenses purport to offer better nighttime driving vision, which may be especially helpful in patients with previous refractive surgery, but it can be difficult to quantify this benefit except through contrast sensitivity testing.

Clinicians should remember that reduced spherical aberration can result in a narrower depth of focus at near. That is why a monofocal lens such as the Tecnis has the sharpest distance vision — if centration, tilt and alignment are all perfect — because it is a negative aspheric lens, and the trade-off is a loss of depth of field at near. The Akreos, on the other hand, is neutral aspheric, so it balances great distance vision (but not as sharp as the Tecnis with everything aligned perfect) and a larger depth of focus.

Toric lenses

Toric lenses include the Staar Toric and the Alcon Toric. Designed to correct astigmatism, these lenses may also be aspheric.

Toric IOLs require surgical alignment with the axis of any astigmatism that is likely to remain following lens removal. This requires accurate measurement of preoperative corneal astigmatism with keratometry or (better) topography or optical biometry (with IOL Master). Surgeons must also factor in any surgically induced astigmatism in their plan.

Because lenticular astigmatism does not play a role after lens removal, the preoperative manifest astigmatism, which is influenced by lenticular astigmatism, is not generally used to plan surgery.

Multifocal lenses

Multifocal lenses approved in the United States include Alcon’s AcrySof ReStor, AMO’s ReZoom and the Tecnis Multifocal. Like a bifocal contact lens, these IOLs have two separate focal points. By “neuroadaptation,” patients can perceive sharp focus at both distance and near.

The ReStor and Tecnis multifocal IOLs have a surface with concentric rings that act like Fresnel lenses to provide distance and, with an effective add of 3.0 D to 3.5 D, near vision.

The ReZoom IOL has two zones for distance and near vision. Its effective add is about +2.25 D.

All of these lenses can provide excellent distance and near Snellen acuity with a high degree of spectacle independence. All have the side effect of perceptible halos around lights and glare from bright light sources. About 10% of patients consider these symptoms to be highly bothersome; despite this, the vast majority are pleased to enjoy reading and driving without spectacles.

Accommodative lenses

Bausch + Lomb’s Crystalens is the only accommodative lens approved in the United States, though Abbott Medical Optics’ Synchrony Lens, a dual-optic accommodating lens, will probably be approved before the end of 2010. Powered by ciliary muscle contraction, accommodative lenses are designed to accommodate much as the natural crystalline lens did in the patient’s youth. These muscles continue to work well at all ages, though they may need some retraining, especially among presbyopic myopes who have not exerted accommodative effort for many years.

With the newest generation Crystalens AO, most patients achieve very acceptable uncorrected near vision. The Crystalens typically requires a modest amount of monovision with a target of emmetropia or plano in the dominant eye and about -0.25 D to -0.50 D in the nondominant eye.

Our recommendations

We believe that both multifocal and accommodative implants have their place in presbyopia correction. Though we continue to use both types of lenses, we have gravitated to using accommodative lenses (Crystalens) for the majority of our cataract patients who wish to have presbyopia correction. This is simply the result of our belief that patients do best with a single point of focus. Our consistent success with these lenses, especially with the newest generation design, has strengthened our belief that accommodation can be meaningfully restored in pseudophakes.

For more information:

• John A. Hovanesian, MD, FACS, is a member of the Primary Care Optometry News Editorial Board and can be reached at Harvard Eye Associates, 24401 Calle De La Louisa, Suite 300, Laguna Hills, CA 92653; (949) 951-2020; fax: (949) 380-7856; e-mail: drhovanesian@harvardeye.com. Dr. Hovanesian has a financial interest in AMO and Bausch + Lomb Surgical.
• Paul M. Karpecki, OD, FAAO, is clinical director of Corneal Services and Ocular Surface Research for Koffler Vision Group and a member of the PCON Editorial Board. He can be reached at 120 N. Eagle Creek Drive, Ste 431, Lexington, KY 40509; (859) 227-7781; fax: (859) 263-5694; e-mail: paul@karpecki.com. Dr. Karpecki is a paid consultant to Bausch + Lomb.