My Firsthand Experience with the nanoFLEX^® Collamer^® IOL

What makes this IOL so beneficial to patients and therefore a valuable addition to my practice?

By Alan N. Carlson, MD

Incorporating any new technology or product into a clinical practice requires a meticulous evaluation of the potential benefits, but even more important is assessing the risks, obstacles and any “negatives” that might be encountered along the way. This is the approach I’m taking as I share my experience and assessment of the STAAR Surgical nanoFLEX^® Collamer^® IOL and how it fits nicely among the many options available to cataract surgery patients.

Material & Design Benefits

Based on my experience of implanting just under 2,000 nanoFLEX IOLs, the clarity of the Collamer material is extraordinary. This clarity contributes to a consistent and excellent quality of vision enjoyed by patients. The lens incorporates a UV filter, without tint or loss of visible spectrum, and I haven’t noticed the formation of vacuoles, glistening or discoloration over time. Additionally, the clarity of vision is achieved promptly, which adds an important efficiency to combination cataract/retina surgeries, which we perform a lot of in my university practice. When I use the nanoFLEX, I remove the cataract and implant the IOL, and right away the retina surgeon has good visualization for the posterior segment portion of the procedure. While acrylic IOLs offer excellent quality as well, for combination procedures that require meticulous visualization of the retina, I usually have to remove the cataract and then scrub back in after the retina procedure to implant the IOL because the retina surgeon’s view to the posterior segment may be delayed by the unfolding crease that may not immediately resolve with the acrylic IOL in place.

In combination with the Collamer material, other design attributes of the nanoFLEX IOL offer definite advantage. This includes the index of refraction and thickness profile, making optic reflection less visible to other people. Several of my patients have commented to me how friends and family notice in certain lighting the reflection in their eye from a lens other than the nanoFLEX. One of them, a grandmother, inquired about getting a new lens because her young grandson didn’t like her “Harry Potter” eye. Similarly, the Collamer material, dimensions and design of the nanoFLEX make dysphotopsia, which can be a very frustrating phenomenon for patients and surgeons, less likely than with other IOLs.

What About Plate Haptics?

The design of the nanoFLEX Collamer IOL includes plate haptics, which some surgeons tend to want to avoid. In my opinion, this tendency is outdated. More than 20 years ago, I first reported at the American Academy of Ophthalmology meeting the dislocation of silicone plate IOLs following YAG laser. That presentation and the subsequent similar experiences of other surgeons created an overall concern about plate lenses. However, the nanoFLEX Collamer IOL is a very different lens than its silicone plate haptic predecessor from Chiron. It doesn’t produce the same “perfect storm” resulting from the “springiness” of silicone, the length of the older lenses, and capsular contraction and tension that led to a large capsular split after the first or second YAG laser pulse causing subsequent IOL dislocation.

That said, success with a plate haptic IOL does require an excellent and consistent surgery. If the anterior or posterior capsule or zonular support are compromised in any way, thus inviting imbalanced forces to come to bear on the capsule, a plate haptic is more of a liability than a loop haptic. However, when surgery goes as planned, including the creation of a perfectly round capsulotomy, the centering of the nanoFLEX is second to none and the lens appears to retain that centration over time and may be more resistant to decentration than lenses with loop haptics.

Several factors are related to the rate of PCO development associated with any given IOL. These include edge design, lens material and type of contact between the optic and posterior capsule. PCO rates for many of today’s IOLs have been higher than the rates surgeons were accustomed to with square-edged lenses that were posterior vaulted against the capsule. These new designs have been changing in an effort to reduce unwanted optical effects such as dysphotopsia. The nanoFLEX isn’t an exception to this. I find that I perform YAG capsulotomy for PCO in approximately half of my nanoFLEX patients within six months after their surgery. Fortunately, the nanoFLEX is extraordinarily easy and forgiving with respect to the YAG laser procedure. It’s easy to focus on the capsule and avoid hitting the IOL, but even if that happens, it’s somewhat reparative nature reduces pitting as is seen more commonly with acrylic or PMMA materials, which could be optically significant for some patients. In my opinion, the need for YAG capsulotomy with the nanoFLEX lens is acceptable in light of the good quality of vision it provides.

Delivering Desired Outcomes

The nanoFLEX Collamer IOL, a monofocal lens, has been shown to rival the Crystalens accommodating IOL in terms of clarity and depth of focus.¹ The Collamer Accommodating Study Team (CAST), a group of eight U.S. cataract/refractive surgeons assembled by STAAR Surgical, began implanting and evaluating this lens in 2008. In phases one and two of their multi-phase, ongoing study, the CAST investigators found that patients implanted bilaterally with nanoFLEX lenses and subsequently emmetropic had unaided binocular intermediate vision of 20/25 on average and unaided binocular near vision of 20/46 on average. When a blended vision strategy is employed using the nanoFLEX lens, results are impressive. In a study by Kenneth Lipstock, MD, patients who received nanoFLEX with blended vision had on average near reading acuity comparable to and intermediate reading acuity superior to (according to published data) all IOLs designated as presbyopia-correcting by the FDA.²

This type of visual outcome has helped to make the nanoFLEX a very popular IOL in my practice. About 60% of my cataract surgery patients receive a monofocal IOL, and most often it is the nanoFLEX IOL. They also have the option of making the nanoFLEX part of a premium surgical package that includes pre-treatment with the LipiFlow (TearScience) thermal pulsation device to ensure the health of the ocular surface and femtosecond laser-assisted surgery with astigmatism management. Many patients who come in thinking they’d like to have premium surgery with a multifocal or accommodating IOL end up opting for the nanoFLEX premium procedure because without the extra costs of the lenses designed to correct presbyopia, it is significantly less expensive. At the same time, they can minimize the amount of time they need to wear glasses during their typical day. Most of them are looking for good distance and intermediate vision unaided, which the nanoFLEX can provide, and find this an excellent option despite not having perfect unaided near vision.

I’d encourage surgeons who haven’t tried the nanoFLEX Collamer IOL to see firsthand what it can do for their patients and practice. Since I started using it slightly more than 3 years ago, it has become a great addition to my practice, especially for patients who want the “premium” outcome at a lower price point. I’ve implanted the nanoFLEX with confidence in the eyes of relatives and other surgeons, and haven’t had a single patient who has been unhappy with that lens selection. In comparison with all of the other changes today’s cataract surgery practices are undergoing, either by choice or mandate, my adoption of the nanoFLEX IOL has been a breeze. ■

References

Dr. Carlson is a Professor of Ophthalmology and Chief of Corneal and Refractive Surgery at the Duke Eye Center in Durham, N.C. He specializes in anterior segment procedures, including refractive cataract surgery, corneal refractive surgery and corneal transplantation.