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Surgeons report good results with the Square-Round-Edge IOL
The prefolded IOL has a sharp posterior optic edge to fit against the posterior capsule and a rounded anterior edge to prevent glare.
The CV232 Square-Round-Edge IOL from CIBA Vision provides good vision and is easy to implant, according to several surgeons experienced with the lens.
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The CV232 is an acrylic IOL that is delivered prerolled and unfolds in the eye. The lens has received the European CE Mark and Food and Drug Administration approval. It is available in Europe and was expected to be made available in the United States this year.
Jean-Michel Bosc, MD, a surgeon at the Clinique Sourdille in Nantes, France, was involved in clinical trials of the CV232 lens as well as previous CIBA lenses.
The CV232 is the latest IOL to employ CIBA’s thermoplastic acrylic material previously used in the MemoryLens. The MemoryLens was taken off the market because of reports of alumina deposits on the lens. Since that time CIBA has carefully reworked its manufacturing process to eliminate the problems seen with the earlier versions of the lens. New clinical studies were done in Europe to reintroduce the lens material, and early results are now being reported.
Dr. Bosc said he has not encountered any problems with the lens material in his patients, either before or after the relaunch.
“Since the reintroduction of the lens in September of 2000, I have implanted the lens in 18 patients and have had no complications,” Dr. Bosc said. He implanted about 1,400 of the MemoryLens IOL beginning in 1997.
Dr. Bosc said the CV232 is his first choice for routine cataract surgery. He also uses it in pediatric cataract cases because of its ability to go through a smaller incision. He said one of the main incentives for using the lens is its easy insertion, allowing for faster surgery.
“I choose it because it makes surgery very easy. It’s not time-consuming because you can put the lens very quickly in the eye, and I think the haptic material is very biocompatible,” he said.
Likewise, Matteo Piovella, MD, at the Centro di Microchirugia Ambulatoriale in Monza, Italy, has found the lens to be safe and comparable to other lenses.
“[Because it] is prefolded, it is possible to directly implant it without using any specific folding instrument. This saves times because it takes only a few seconds to implant the lens,” Dr. Piovella.
According to Dr. Piovella, the new CV232 has achieved comparable results in its safety and improvement of visual acuity as the MemoryLens did during the past 12 years.
“The main thing is that in the last 12 years, it was never necessary to wait for the lens to be flat in the capsular bag. Because this step takes about 15 minutes from when you stop to use the cold [balanced salt solution], it’s not really necessary to see the lens flat and open,” Dr. Piovella said.
In a study involving 700 patients, Dr. Piovella examined patients 30 to 90 minutes after inserting the MemoryLens and found the lens open and flat in the bag.
Both surgeons have performed independent studies to ensure the efficacy and safety of the lens.
Introducing the CV232
Dr. Piovella has so far implanted 50 of the new CV232 lenses. He will monitor these cases to evaluate the incidence of posterior capsular opacification.
“Right now, we can only check to see if the lens is completely in touch with the posterior capsule. Naturally, we don’t know about the possibility to decrease PCO until a year to 3 years,” he said.
Dr. Bosc has implanted the new lens in 18 eyes. He reported that by the third postoperative day, visual acuity was 20/25 or better in 80% of eyes. Only one patient had moderate flare which resolved by the third week. There were no other complications.
By the third postoperative week, best-corrected visual acuity (BCVA) was 20/25 or better in 85% of cases and 20/20 in more than 50%.
“I think the reintroduction of MemoryLens shows that this IOL is safe,” Dr. Bosc said.
Properties of the lens
The new lens is made of a thermoplastic material and comes prefolded by the manufacturer. The haptics are made of polypropylene, which has in previous studies been linked to bacterial adhesion.
However, this does not appear to be a factor in tests performed on the CV232. Dr. Bosc cited a study done by Thomas Neuhann, MD, in which the lens was tested against a PMMA lens. The material exhibited less adherence by bacteria than PMMA, Dr. Bosc said.
“The materials were exposed to contamination by Staphylococcus epidermidis bacteria … by immersion in [balanced salt] solution containing different concentrations. After 15 to 30 minutes of exposure, the materials were viewed. Results showed less contamination for the MemoryLens,” Dr. Bosc said.
The lens also has other advantages. Its ability to fold and be inserted without an injector makes it appropriate for pediatric cases, he said.
“Another thing that’s important is the hardness of the material. It’s the hardest material for a foldable lens. It’s important in cases where you have vitreous dispersion or a difficult eye. Nobody has talked about that, but it’s very important,” he said.
Another important characteristic of the lens is that the rounded anterior edge prevents glare and protects against optical aberrations, Dr. Piovella said.
In addition, the thermoplastic material “allows it to be folded in a way so the thickness of the lens is always the same; there is no possibility the lens can have different thicknesses along the axis of the folded lens,” Dr. Piovella said.
For Your Information:
- Jean-Michel Bosc, MD, can be reached at the Clinique Sourdille 3, Place Anatole France, BP 84616-44046, Nantes, Cedex 1: +(33) 2-51-77-10-50; fax: +(33) 2-51-77-16-88; e-mail: jmbosc@aol.com. Ocular Surgery News could not confirm whether Dr. Bosc has a direct financial interest in any of the products mentioned in this article or if he is a paid consultant for any company mentioned.
- Matteo Piovella, MD, can be reached at Centro di Microchirugia Ambulatoriale, Via Donizetti 24, Monza, 20052, Italy; + (39) 039-389-498; fax: + (39) 039-230-0964; e-mail: piovella@piovella.com. Ocular Surgery News could not confirm whether Dr. Piovella has a direct financial interest in any of the products mentioned in this article or if he is a paid consultant for any company mentioned.