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My Phakic Lens Experience:Why we prefer AcrySof® CACHET® Phakic Lens

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Supplement April 2012

Friday 16 September 2011

For phakic intraocular lenses (IOLs), achieving excellent short-term visual outcomes has been the easy part. “A high percentage of patients improve one line or more in best spectacle-corrected vision, and even a

two-line improvement in the neighbourhood of 15% [of patients] is consistent with all phakic IOLs,” said Stephen S Lane MD, clinical professor at the University of Minnesota and medical director at Associated Eye Care, Minneapolis, Minnesota, US.

Safety and ‘wow’ The AcrySof® CACHET® Phakic Lens (Figure 1) five-year data presented by Dr Lane from phase three trials in Europe and Canada, and phase two trials in the US look good. The 160 patients who have reached five years, at the time of analysis, achieved mean uncorrected visual acuity better than 20/25 and best spectacle-corrected better than 20/20. More than 55% gained one line or more of best spectacle-corrected vision at one and five years.

Mean manifest refraction spherical equivalent with the AcrySof® CACHET® Lens is very stable over time. Results of manifest refraction one day post-op (355 patients), one year (349 patients) and five years (160 patients) are -0.13, -0.24 and -0.26 logMAR (Figure 2). “This proves the excellent uncorrected visual acuity of the lens,” said Dr Lane.

“Another important factor in refractive surgery is patient satisfaction. We conclude that patients implanted with the AcrySof® CACHET® Lens are happy. One year after implantation, 97% of the patients state that they would have the same lens implanted again if they could choose. The satisfaction does not decrease with time; after five years, 97% would still have done the same implantation. These are the patients who say ‘wow’ and give you a hug because they are so happy with their vision.”

Safety also shows good results (Figure 3). No iridectomies were performed for pupillary block. Cataract formation was observed in 3.6% of patients including patient aging. Raised intraocular pressure requiring treatment more than one month after surgery occurred in 2.8%. Pupil ovalisation greater than 1mm was minimal and only noted in two eyes (0.6%). “This is very different from former rigid anterior chamber phakic lenses. With the rigid lenses, pupil ovalisation typically occurred within months after surgery. Published studies suggest pupil ovalisation is high (approximately 35%) with rigid lenses.3 This is very different from what we saw in lenses made with the AcrySof® IOL hydrophobic acrylic IOL material,” Dr Lane said.

Better Material + Better Design = Better Outcomes

At five years, AcrySof® CACHET® Phakic Lens shows excellent vision, minimal complications

My Phakic Lens Experience: Why we prefer AcrySof® CACHET® Phakic Lens


“ Not only refractive outcome, looking into results of patient satisfaction with AcrySof® CACHET®, we can conclude that the patients are happy”

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Stephen S Lane MD

Figure 1: AcrySof® CACHET® Phakic Lens product attribute1

Figure 2. MRSE (Manifest Refraction Spherical Equivalent) stability2

Figure 3. Adverse Events (N=360)4



“ For five years adverse events have been minimal”

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Endothelial cell density results were also positive, suggesting that the CACHET® Lens maintains adequate endothelial clearance. Acute ECD losses caused by surgery is on average -3.3% centrally and -3.0% peripherally. The chronic endothelial cell loss, which should be monitored for all phakic IOLs, was measured from six months’ post-op. From six months to five years post-op, mean chronic central cell density declined at about 0.1 to 1.1% annually, close to the physiological figure of about 0.6%5, Dr Lane noted. However, observed loss rates of 1.1% were higher in the fourth and fifth years than in the first three years (Figure 4). This may be due to a lower number of patients followed for more than three years, Dr Lane said.

Better by design Dr Lane believes that the combination of material and unique design gives these outstanding clinical results. The lens delivers the advantages of the angle supported concept, such as easier implantation and reduced need for peripheral iridotomy and iridectomy, while minimising the weaknesses of earlier designs and materials.

The CACHET® Lens is an anterior chamber angle-supported lens with the refractive powers ranging from -6.0 to -16.5 D. It has 6.0mm optic and overall lengths of 12.5, 13.0, 13.5 and 14.0mm. The length is designed to maintain appropriate vault. “It’s not a one-size-fits-all; however, the design of the haptic feet make the CACHET® Lens a very forgiving lens and the AcrySof® CACHET® Phakic Lens online calculator helps the lens choice, he noted.

Alcon’s AcrySof® IOL hydrophobic acrylic Lens material helps distinguish the CACHET® Lens, Dr Lane said. Its biocompatibility is proven in more than 50 million cataract implantations. AcrySof® Lens material is flexible enough that the haptics can stabilise the lens against angle tissues with very little compression, but stiff enough to maintain lens vault. It also can be folded for insertion through a 2.6mm incision that minimises surgically induced astigmatism.

Design is also critical. Dr Lane notes that CACHET® Lens haptics are designed to maintain a vault of about 0.5mm over the anterior surface of the crystalline lens. We need a platform with very low vault response. “What we are looking for is the lens placed about one-third of the distance away from the natural lens and two-thirds away from the cornea. This minimises lens-related endothelial cell loss, premature cataract formation and without excessively stressing delicate angle tissues. AcrySof® CACHET® Phakic lens is the lens I look forward to being approved in the US, so that more patients can benefit from this lens,” Dr Lane said.

Stephen S Lane – [email protected]

References1. Direction of Use. Model AcrySof® CACHET® Phakic Lens.

Alcon Inc. 2,4,6 Results of multicenter implant clinical study of the AcrySof®

CACHET® Phakic Lens. Please see the AcrySof® CACHET® Phakic Lens. Direction for Use.

3. Thomas Kohnen et al, JCRS 2010; 36:2168-2194.5. Bourne WM, Nelson LR, Hodge DO. Invest Ophthalmol Vis Sci

1997; 38:779–782.Figure 4. Mean chronic change in central ECD, baseline six months’ post-op (annualized)6

With more than a dozen years implanting phakic IOLs – iris- and angle-supported, rigid and foldable – Rudy M M A Nuijts MD, PhD, associate professor at the Academic Hospital, Maastricht,

The Netherlands, is intimately familiar with both the advantages and risks of phakic IOLs compared with other refractive surgery options.

On the plus side, phakic IOLs are removable and therefore reversible, unlike laser corneal procedures. For high myopes, phakic IOLs often produce gains in best-corrected visual acuity because they reduce minification of images at the retinal plane, and typically induce less aberration than laser surgery.

On the minus side, phakic IOLs are critically dependent on adequate anterior chamber depth, and healthy corneal and anterior chamber morphology – and these can change over time. Because its design and materials provide an extra margin of safety, the AcrySof® CACHET® Phakic Lens may be more forgiving than earlier phakic IOLs. Nonetheless, careful patient selection and diligent follow-up still are essential to ensure long-term safety and success, Dr Nuijts stressed.

Select for success Based on his clinical experience, published evidence and guidelines from Alcon, Dr Nuijts recommended several criteria for implanting the AcrySof® CACHET® Phakic Lens.

Dr Nuijts starts his examination checking corrected and uncorrected visual acuity, objective refraction with and without cycloplegia, subjective refraction and review of spectacle and contact lens use. To ensure refraction stability, Alcon recommends a minimum implant age of 21. However, high myopes may progress well into their 20s. Stable refraction for 18 months to two years may be a more reliable indicator.

Dr Nuijts also looks at keratometry, oculometry, anterior segment depth and anatomy, pupillometry in scotopic, mesopic and photopic conditions, corneal topography and tear film stability. Pachymetry and specular microscopy for endothelial analysis and white-to-white measurements are extremely important, he said.

In terms of morphology, Dr Nuijts looks for a mesopic pupil size of 7.0mm or less to minimise glare and haloes from exposure of the optic edge at night. Anterior chamber depth should be 3.2mm or more including corneal thickness.

“This is not the AcrySof® CACHET® indication or recommendation, however, I look at the anterior chamber anatomy and iris configuration.” From Dr Nuijts’s long-term, anterior chamber iris-fixated phakic lens experience; he also makes sure that the distance from the natural lens surface to the endothelium is at least 2.8mm. Also, the distance from the implanted phakic IOL optic centre to the endothelium should be at least 2.0mm, and from the optic edge to the endothelium 1.5mm.

Dr Nuijts’ anterior chamber iris-fixated phakic lens research shows that the proximity of the phakic IOL edge to the endothelium correlates strongly with endothelial cell density loss.1 Extrapolating from his findings, a distance

of 1.66mm, or the mean minus one standard deviation, results in ECD loss of just 0.2%, which means a phakic IOL could stay almost indefinitely in an eye with an initial density of 2,600. But at 1.2mm, or one standard deviation below the norm, ECD loss reaches 1.7%, leaving just 20 years in the eye.2

The Orbscan*, Pentacam* and Visante* OCT all can be used to measure anterior chamber depth and diameter, Dr Nuijts said. However, he warned that readings among the devices are not interchangeable. He also cautioned that the vertical and horizontal anterior chamber diameters differ with the vertical typically a bit larger. “You need to look at the map and find the largest diameter, and that is the one you should use in calculating your lens power.” Topography is also important. “You need to rule out irregular astigmatism or corneal warpage.”

Following-up Avoiding touching the lens or endothelium during surgery is essential to minimise surgical endothelial cell loss or induced cataract. Dr Nuijts also cautions against intraocular pressure spikes that can lead to permanent mydriasis, or Urrets Zavalia syndrome. “It’s important to instruct the patient not to aggressively rub their eyes and to avoid direct eye trauma.”

At one week, one month and three months, Dr Nuijts checks patients’ visual acuity and IOP, and conducts a slitlamp exam and corneal topography. At six and 12 months, and annually thereafter, they receive the full exam plus specular microscopy to check for endothelial cell loss, which can commence at any time.

Because of the long-term follow-up and behavioral requirements, Dr Nuijts emphasises the need to examine patients’ motivations and expectations. Patients with a strong desire to get rid of glasses, or who have functional or occupational needs, tend to be good candidates. Patients with unrealistic expectations for near vision, who are excessively critical, who want to wear glasses, or participate in activities that may lead to eye trauma are less desirable.

“And beware of people who rub their eyes,” Dr Nuijts warned.

Rudy Nuijts – [email protected]

References1. Muriël Doors, Diana W.J.K. Cals, Tos T.J.M. Berendschot, John

de Brabander, Fred Hendrikse, Carroll A.B. Webers, Rudy M.M.A. Nuijts. Influence of anterior chamber morphometrics on endothelial cell changes after phakic intraocular lens implantation. Journal of Cataract & Refractive Surgery, Volume 34, Issue 12, December 2008, Pages 2110-2118.

2. Muriël Doors, Tos T. J. M. Berendschot, Carroll A. B. Webers, and Rudy M. M. A. Nuijts. Model to Predict Endothelial Cell Loss after Iris-Fixated Phakic Intraocular Lens Implantation. IOVS February 2010 51:811-815.

* Trademarks are the property of their respective owners

Patient Selection and Follow-Up

Anterior chamber morphology is critical – and changes. Monitoring is essential for success



“ It’s important to instruct the patient not to aggressively rub their eyes and to avoid direct eye trauma”

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Rudy M M A Nuijts MD, PhD



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Antonio Marinho MD of Hospital Arrabida, Porto, Portugal, has long been interested in phakic IOLs. He considers the AcrySof® CACHET® Phakic Lens to be one of the best he’s worked with.

Alcon’s proven hydrophobic acrylic material is one reason. “What attracted me to this material is its established history from cataract surgery. Over 50 million AcrySof® cataract lenses have been implanted worldwide,” Prof Marinho said.

The flexible haptics allow easier placement with less stress on the angle tissues than other designs, without sacrificing stability, Prof Marinho added. Shooting for 1.0mm of compression, he typically uses OCT to measure anterior chamber diameter and adds 1mm to choose the proper lens size. This usually works, though it is difficult to precisely measure the degree of haptic compression in clinical practice. Results, Prof Marinho said, have been exceptionally good. In 66 eyes in 38 patients, “emmetropia was achieved in almost every case.”

Refractive outcome All of the eyes were moderate and high myopes, with a mean sphere of -8.15 D, ranging from -4.0 to -18.0 D (the spherical power indications are outside of the current spherical range of AcrySof® CACHET® Phakic Lens, -6.0 to -16.50D, due to spherical equivalence and surgeon preference.) Mean pre-op cylinder was -0.89 D, ranging from 0.0 to -2.50 D*. White-to-white anterior chamber diameter averaged 11.82mm, ranging from 11.25 to 12.70mm. Mean anterior chamber depth was 3.74mm, ranging from 3.2 to 4.39mm.

The refractive outcome in these eyes is excellent (Figure 5). The mean post-op spherical equivalent was -0.10 D. “One eye at -1.50 D skewing the mean value, the case which had -18.0 D preoperatively and ended with undercorrection as it was anticipated,” Prof Marinho said. He uses the CACHET® Phakic Lens in eyes up to about -2.0 D cylinder. “Normally I use a 12 o’clock incision, but for these cases I make the incision in steepest meridian, and larger, 3.2mm instead of 2.6mm. This can correct 1.0 to 1.5 D of cylinder. This incision control helps to achieve better refractive outcome as well. ”

In my experience, the CACHET® Phakic Lens has caused no intraocular inflammation. “In 66 eyes I have not had any deposits on the lens including one very young patient, where the inflammatory potential is much higher,” Prof Marinho said. As a result, he prescribes only two weeks of post-op steroids, the same as for cataract patients. “This is completely different from other phakic lenses where you have to do four to six weeks of steroids.”

Lens position “The position of the AcrySof® CACHET® Lens in the eye has shown to be stable in my series of patients,” Prof Marinho says. Using Heidelberg OCT, Prof Marinho measured the multiple distances three to six months’ post-op. The mean from the optic centre to endothelium was 1.99mm ranging from 1.6 to 2.48mm. The anterior lens surfaces sat at a mean 63% of the anterior chamber depth, ranging from 56 to 77%. The mean distance from lens edge to endothelium was 1.35mm ranging from 1.07 to 1.70mm, or 43% of total anterior chamber depth ranging from 38 to 50% (Figure 6).

“From my clinical observation, this figure can be used to estimate how much clearance the lens edge will have after implantation. Stable endothelial counts at two years also suggest the lens maintains its position in the eye,” Prof Marinho said.

“In our series of the AcrySof® CACHET® Phakic Lens Implants, complications were minimal, confirming the conclusions of the previously published clinical trials. We have not seen any pupil distortion or iris atrophy and this is different from what we have experienced previously with the rigid lenses,” Prof Marinho said.

“In addition to the minimal rate of complications, the AcrySof® CACHET® Phakic Lens shows excellent refractive results and stability in the eye,” Prof Marinho concluded.

Antonio Marinho – [email protected]

My Personal AcrySof® CACHET® phakic lens Experience

Emmetropia in nearly every case and reduced need for anti-inflammatory medications

“ The position of the AcrySof® CACHET® Lens in the eye has shown to be stable in my series of patients”

Antonio Marinho MD

Figure 5. Refractive outcome SE (Spherical Equivalence)* AcrySof® CACHET® Phakic Lens Directions for Use indicates that a cylinder > 2.0 D is

the contraindication

Figure 6. AcrySof® CACHET® Lens Position (3-6 months post-op)

Data on hundreds of patients around the world confirm that the AcrySof® CACHET® Phakic Lens delivers good visual results with minimal complications up to five years, said Thomas Kohnen

MD, PhD of the Goethe University, Frankfurt, Germany.His own studies show minimal change in lens

position at three years,1 and lens position change due to accommodation is minimal.2 Combined with relatively low endothelial cell loss, these numbers suggest the CACHET® Lens is stable in the eye, which is essential for long-term safety. “Of course we have to continue monitoring,” Prof Kohnen said.

How can the excellent results reported in clinical trials be achieved with every patient? Based on research and clinical experience, Prof Kohnen offered advice in five areas to optimise outcomes.

1. Indications A good refractive outcome starts with a good patient selection based on medical decisions. It is well known that the corneal laser procedures work well up to about -8.0 D. But concerns about ectasia, quality of vision and corneal curvature make phakic lenses a better option for the patient with moderate to high myopia, Prof Kohnen said. Especially, they may be better suited for moderate myopes with thin corneas, he noted.

Prof Kohnen also emphasised that pupil size of 7.0mm or less and an anterior chamber depth of at least 3.2mm including cornea are essential, as are endothelial cell counts commensurate with age. Absence of glaucoma and corneal pathologies are also necessary to get promising outcomes.

2. Minimally invasive surgery To minimise induced astigmatism and trauma to the eye, Prof Kohnen advocates minimally invasive surgery. He uses topical anaesthesia rather than an injection. “Patients can see immediately with topical anesthesia. Also an iridotomy or iridectomy are not necessary, so immediate good visual outcomes can be expected. In my series of 250 eyes I have never touched the iris for an iridectomy,” he said.

Prof Kohnen makes a single incision with 2.6-2.7mm clear corneal incision to implant the CACHET® Lens. “I call it the single incision implantation technique. The only challenge of this technique is viscoelastic removal because we can’t have a bimanual operation.”

He says it is also important to be careful when the lens is implanted. The lens injection begins slowly, then speeds up to prevent the lens from opening in the incision. Then he places the haptics, being careful not to touch the tissues.

After the lens is inserted, viscoelastic is cleared using passive irrigation. The surgery ends with a little antibiotic in the anterior chamber, though the benefit of this has not been proven for phakic IOLs, Prof Kohnen noted. The wound is closed without a suture. “2.6mm is small enough; you do not need to suture.”

Prof Kohnen mentioned his experience with the removal procedure of the AcrySof® CACHET® Phakic Lens. “We had one case which had a scratch on the lens, and I didn’t want to leave it in the eye.” He enlarged the incision to 3.2mm, and easily removed the lens with forceps. “You can do this without any complex procedure. It is very easy to explant and this is important because any phakic lenses need to be explanted one day prior to a cataract surgery.”

3. Astigmatism control “You need to pay attention with astigmatism control because otherwise your patient will not be happy,” Prof Kohnen said. For pre-op astigmatism of less than 1.0 D, he makes the 2.6mm incision on the steep meridian. “Most of the time with a 0.75 cylinder you can reduce it enough to make the patient happy. For pre-op cylinder from 1.0 to 2.0 D, Prof Kohnen makes his incision on the steepest meridian and adds a limbal relaxing incision or an OCCI (opposite clear cornea incision) on the opposite side. “Sometimes we can enlarge the incision to titrate it.”

4. Post-op meds “We have changed our post-op meds. In 2008 to 2009, we used four weeks of steroids and two weeks of antibiotics. In 2010 we went to two weeks of steroids and antibiotics. We have not had any problems,” Prof Kohnen said.

In fact, reducing steroids to two weeks may help avoid post-op intraocular pressure problems, Prof Kohnen added. “As you know pressure problems with IOP usually occur after two weeks. Reducing the steroids because of the minimally invasive surgery helps to avoid IOP problems.”

5. Faster recovery “I think faster recovery is a key factor to have patient satisfaction from the refractive surgery,” Prof Kohnen said. In his experience, 85% of patients achieved 20/25 and 69% 20/20 one day post-op. With the AcrySof® CACHET® Lens, the patient’s reaction to immediate visual recovery is very positive, Prof Kohnen said. By contrast, patients receiving rigid lenses with incision up to 6mm often take weeks to recover, dampening their enthusiasm.

Of course, safety demands ongoing follow-up. Prof Kohnen recommends a baseline cell count and central and peripheral endothelial cell density readings yearly thereafter. “Patients really want to have quick visual recovery, and these lenses are wonderful. At the same time, we have to tell the patient the importance of annual examinations. Severe complications can be avoided by annual examinations.”

Thomas Kohnen – [email protected]

References1. Kohnen T, Klaproth OK. JCRS 2010; 36:1120-1126.2. Klaproth OK et al. ESCRS Winter Meeting 2011.

Optimising AcrySof® CACHET® Phakic lens Outcome

Surgical pearls for better outcomes with faster recovery



“People really want quick visual recovery, and these lenses are wonderful. At the same time, we have to tell the patient of the importance of annual examination”

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Thomas Kohnen MD, PhD

Why use the AcrySof® CACHET® Phakic Lens? Antonio Marinho MD of Hospital Arrabida, Porto, Portugal, offers two answers because it is really two questions.

“The first question is why a phakic IOL? And if you are using a phakic IOL, why the CACHET® Lens?” Prof Marinho asked.

Answering the first question, phakic lenses are ideal because they are highly predictable and the refraction is very stable compared with LASIK for the patient who has moderate to high myopia. Especially, in certain ages of patients, phakic lenses are preferable to refractive lens exchange because of preserved accommodation, Prof Marinho noted. Also, visual outcomes are typically very good, with patients often gaining lines of best corrected vision, and good quality of vision, he added.

Why the CACHET® Lens for phakic IOL candidates? It comes down to excellent outcomes and ease of use compared with alternatives.

Prof Marinho notes that posterior chamber phakic IOL design requires precise sizing to achieve desired lens vault. If the lens is undersized, it may touch the crystalline lens and cause a cataract to form. If it is oversized, excessive vault and angle closure may occur. “Also, you can only measure the distance from sulcus to sulcus using UBM, not white-to-white, so it’s not easy to obtain proper sizing. Though sizing is important with the CACHET® Lens, it’s measurable using white-to-white, and the flexible haptic design makes the sizing process more forgiving than with posterior chamber phakic IOL design.”

Iris-supported lenses are another alternative. Toric versions are good for patients with high cylinder. But while they are one-size-fits-all, they require surgeons to master the technique of attaching the claw haptic to the iris. “I don’t think it is difficult, but some beginning surgeons feel it is a little difficult,” Prof Marinho said. The CACHET® Lens, on the other hand, is simple for any surgeon to implant.

With the CACHET® Lens, visual recovery is immediate, and inflammation is so minimal that steroids can be stopped at two weeks. And iridotomy is rarely needed. “The technique is simple and there are minimal complications,” Prof Marinho concluded.

Antonio Marinho – [email protected]

Why I prefer the AcrySof® CACHET® Phakic Lens

For moderate to high myopia, it may be the best refractive choice



“ Sizing is important with CACHET® Lens, however it is measurable using white-to-white and its flexible haptic design makes the sizing forgiving”

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Antonio Marinho MD

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