IOLs: a wide selection of new products from which to choose

As cataract surgery increasingly becomes a type of refractive surgery, aberrometry and accommodation become concepts in IOL design.

ROME – Now that cataract surgery is increasingly aimed at visual rehabilitation, IOL selection is becoming more and more a crucial issue.

“There is a wide range of products on the market, and it’s up to us to choose what we think is best for our patients,” said Vittorio Picardo, MD, chairman of a roundtable on IOLs (moderated by Lucio Buratto, MD, and Antonio Scialdone, MD) at the meeting of the Italian Ophthalmologic Society.

He said that surgeon preferences may vary among piece, silicone, hydrophilic and hydrophobic acrylic, and that manufacturers offer a wide variety of models, materials and designs in single- and multi-piece designs.

“There’s a continuous updating of the products, which is based on increasingly advanced designs of the optic surface, optic edge, haptic design, and on increasingly better materials to improve durability, compliance and safety,” he added during a panel discussion on the main advances in IOL construction.

Edge design

The first issue concerned the advantages of the square edge of the optic, which many manufacturers have introduced in recent IOL models. With this design, some IOL materials have shown a decreased rate of posterior capsular opacification. Studies by David J. Apple, MD, and colleagues have documented PCO rates for some of these materials.

“Capsule fibrosis and secondary cataract are nowadays the main problems of cataract surgery, and our efforts should be aimed at finding an effective and definitive solution to this problem,” said Alessandro Galan, MD. “Some lens materials, like silicone, which got the blame for PCO a few years ago, have been largely exculpated. More recent studies have shown that the crucial point is the design of the lens in preventing opacification.”

“While the posterior square edge design of the optic has greatly reduced the incidence of secondary cataract, the latest developments of optic design, with posterior square and anterior round edge like Allergan OptiEdge, or with sanded square edge like Alcon Acrysof, have effectively reduced night glare and halos,” added Antonello Rapisarda, MD.

According to Dr. Galan, the OptiEdge Sensar is “the best you can get,” as you have in one lens all that is needed to prevent complication and produce the best functional result.

“Glare can originate in the space between the two edges. There are studies in progress examining this optical problem,” he said.

According to Dr. Picardo, there are some ongoing studies addressing these optical problems.

Optic surface

Tecnis IOL (Pharmacia) optimizes visual quality by improving contrast sensitivity and correction optic aberrations.

As cataract surgery is today facing the issues and problems of refractive surgery, aberrometry is becoming a familiar concept. Dr. Picardo pointed out that the new Tecnis IOL (Pharmacia) has an optical surface designed to optimize visual quality by improving contrast sensitivity and correcting optic aberrations.

“It is an interesting lens, which promises better functional results than other IOLs,” said Scipione Rossi, MD.

“On average, the total aberration of the eye is slightly positive, and this lens, which is slightly negative, brings it down to zero. It is also aberration-free, which is very important if we consider that we usually introduce a certain amount of new aberrations when we implant a lens in the eye,” he explained.

However, Leopoldo Spadea, MD, said that we should not expect miracles.

“It is proven that optic aberrations change over the years. Also, there is so much variability. There are almost as many aberration patterns as there are individuals. To some extent, a lens can attempt a correction, but it will be little more than the best possible compromise,” he said.

Haptics

Lens haptics are essential for stability and centration. They also play a role in combating capsular fibrosis and opacification. In the past few years manufacturers have produced a wide range of haptic designs to improve these properties.

Dr. Rapisarda discussed his experience with the new single-piece AcrySof by Alcon.

“I have implanted many of these lenses. They are easy to fold and the soft L haptic design gives them a better, more secure fit in the capsular bag. The glazed periphery of the optic prevents glare, and they have a maximum dioptric power of +34 D, which is quite unique. On the whole, they are among my favorite lenses,” he said.

Although it is normal for all types of IOL haptics to give slightly under the pressure of the capsular bag, Dr. Picardo reported that the three-piece AcrySsof remains one of the most stable lenses, with minimal axial displacement.

Meeting all needs

The three models of the Akreos line by Bausch & Lomb are designed to respond to special needs in IOL implantation.

“These lenses are hydrophilic acrylic and are available in a range of different shapes and dimensions, according to dioptric power. For instance, high myopic eyes can be fitted with a lens that is larger than average, in line with the concept of ‘no space, no cells’,” said Giorgio Lofoco, MD.

AcrySof IOL (Alcon) with its sanded square edge, effectively reduces night glare and halos.

The Akreos line of IOLs (Bausch & Lomb) are hydrophilic acrylic and are available in a range of different shapes and dimensions.

“The Fit model is similar in design to the AcrySof. The Adapt has four-point fixation haptics for better stability. Finally, the Disc provides the widest contact angle with capsular bag. No problem with implantation, especially when using injectors,” he added.

Also, IOLTECH has its own hydrophilic acrylic, the XL Stabi. The lens has a tripodal haptic design with 10° angulation and an enlarged 6-mm diameter.

“The stability of this IOL and large surface of contact with the posterior capsule considerably lower the rate of PCO,” Dr. Picardo said.

The XL Octo model, on the other hand, has the advantage of being able to pass through a very small incision.

“For this reason, I particularly like using it in combined glaucoma-cataract surgery,” Dr. Picardo said.

The lens is available in a wide range of dioptric powers. It can be implanted with an injector and is extremely delicate when unfolding in the bag, according to the surgeon.

Accommodative IOLs

Another concept that has recently made its entrance into cataract surgery is accommodation. At the moment, there are two accommodative IOLs in development: the C&C Vision CrystaLens and the HumanOptics 1CU.

The CrystaLens has a total diameter of 11.5 mm. It is a biconvex lens made of a third-generation silicone called Biosil, available in a range of 16 D to 28 D powers in 0.5 steps.

“Our results with this lens are in progress. I have two cases of binocular implantation, and they are getting good results for near and distance vision, with good patient satisfaction,” Dr. Picardo said.

He recommended inducing postop cycloplegia in these patients, as the lens, at the end of surgery, must remain in the “vaulting back” position, at close contact with the posterior chamber. The patient should not accommodate for about a week, to allow time for the onset of a slight fibrosis, which makes the lens adhere firmly and position itself correctly in the capsular bag.

The lens reproduces the physiological movements of accommodation in the phakic eye. When the ciliary muscle contracts, the vitreous pressure, along with the simultaneous relaxation of the zonules, makes the lens shift forward. When the ciliary muscle relaxes and the zonule fibers stretch again, the lens returns to its initial position. These results, however, are directly related to the precision of the preop diagnostic measurements (keratometry and biometry).

Uncorrected near vision

The HumanOptics 1CU is a single-piece, hydrophilic acrylic, biconvex IOL with a 5.5-mm optical zone.

The four haptics transmit to the optic the elastic movements induced by the ciliary body.

When the patient is using distance vision, the ciliary body is relaxed, the zonules are stretched and the lens remains in the basic position. When the patient uses near vision, the contraction of the ciliary muscle is transmitted to the haptics, and the optic is pushed forward, just like a natural lens during accommodation.

“This lens needs a fairly small rhexis to allow for safe and comfortable movements into the capsular bag with no risk of displacement. The lens is delicate but manageable, and can be inserted with either injector or forceps. One should use quite a lot of viscoelastic to help implantation maneuvers,” said Prof. Spadea, who is taking part in a multicenter study to evaluate the results of the HumanOptics 1CU.

Prof. Spadea used this lens in nine eyes, and in three patients on whom he performed binocular implantation.

“After 15 days, the lens starts functioning for near vision,” he said. “On average, patients can read the second character without additional correction, and the first character with a near correction of 0.5 D to 2 D. The follow-up is too short, but so far patients are satisfied.”

Dr. Picardo has implanted 11 HumanOptics 1CU IOLs with good results, both from anatomical and functional points of view.

Not of IOL alone

“We shouldn’t rely entirely on IOLs for the solution of all problems. Complications like PCO and glare very largely depend on our surgical skills,” Dr. Lofoco said, despite acknowledging that the new developments in lens manufacturing have certainly brought improvements in cataract surgery.

He recapped the maneuvers necessary to guarantee satisfactory long-term results, such as a well-centered, well-sized capsulorrhexis.

“Sometimes we implant a square-edge lens to prevent PCO and then, at the 1-month postop examination, we realize the optic disc has been pea-podding from the rhexis edge,” he said.

“We must always take into account that the natural contraction of the capsule tends to misshape the rhexis border. If we don’t, we jeopardize the effects of the IOL with our surgical maneuvers. I believe our main concern should be to improve the surgical maneuvers that will allow the implants to function at their best.”

For Your Information:

• Vittorio Picardo, MD, can be reached at Studio Oculistico, Via Nomentana 311, 00162 Rome, Italy; +(39) 06 854-7845; fax: +(39) 068-535-5461; e-mail: eyeboss@vpicardo.it. Dr. Picardo has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Dr. Alessandro Galan, MD, can be reached at the Ospedale Civile Sant’Antonio, Via Facciolati 121, Padua, Italy; +(39) 049-821-6780; fax: +(39) 049-821-6541. Dr. Galan has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Scipione Rossi, MD, can be reached at Via Adige 41, 00198 Rome, Italy; +(39) 068-530-0853; fax: +(39) 068-530-1010; e-mail: s.rossi@idi.it. Dr. Rossi has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Giorgio Lofoco, MD, can be reached at Studio Lofoco, Viale Giulio Cesare 47, 00192 Roma, Italy; +(39) 06-321-5152; fax: +(39) 062-331-7535; e-mail: lofoco@tiscalinet.it. Dr. Lofoco is a paid consultant for Bausch & Lomb.
• Leopoldo Spadea, MD, can be reached at L’Aquila University, Via Vetoio, 67010 Coppito (L’Aquila), Italy; +(39) 086-231-9671; fax: +(39) 086-231-9672; e-mail: lsapdea@cc.univaq.it. Dr. Spadea has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Antonello Rapisarda, MD, can be reached at the Ospedale Umberto I, Divisione Oculistica, Siracusa, Italy; +(39) 093-172-4068; fax: +(39) 09-316-6132. Ocular Surgery News could not confirm if Dr. Rapisarda has a direct financial interest in any product mentioned in this article, or if he is a paid consultant for any company mentioned.

• Allergan can be reached at 2525 Dupont Drive, Irvine, CA 92612 U.S.A.; +(1) 714-246-4500; fax: +(1) 714- 246-5913; Web site: www.allergan.com.
• Alcon Surgical can be reached at 6201 South Freeway, Fort Worth, TX 76134 U.S.A.; +(1) 817-293-0450; fax: +(1) 817-568-6142.
• Pharmacia can be reached at 100 Route 206 North, Peapack, NJ 07977 U.S.A.; +(1) 908-901-8592.
• Bausch & Lomb can be reached at Hamilton House (Block B), Regent Park, Kingston Rd., Leatherhead, Surrey, KT22 7PQ United Kingdom; +(44) 1372-224-081.
• IOLTECH can be reached at Ave. Paul Langevin, BP5, 17053 La Rochelle, Cedex 9, France; +(33) 5-46-44-8550; fax: +(33) 5-46-44-8560; e-mail: ioltech@ioltech.com.
• C&C Vision can be reached at 6 Journey, Suite 270, Aliso Viejo, CA 92656 U.S.A.; +(1) 949-916-9352; fax: +(1) 949-716-8362.
• HumanOptics can be reached at Spardorfer Strasse 150, 90154 Erlangen, Germany; +(49) 9131-506-6586; fax: +(49) 9131-506-6590; e-mail: hahn@humanoptics.com.