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Collamer IOL offers new advantages
Biocompatibility and intraoperative control are among the benefits of the material that combines a polymer with collagen.
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KOLOA, Hawaii — The new Collamer IOL produced by STAAR offers good control during delivery and a quiet anterior chamber postoperatively, said Stephen Bylsma, MD.
In a presentation held at Hawaii 2001, the Royal Hawaiian Eye Meeting, sponsored by Ocular Surgery News in conjunction with the New England Eye Center, Dr. Bylsma also said the IOL is not pitted during YAG laser capsulotomy and allows a smaller incision size. Visual results are also good with the lens.
"The benefits are great control and delivery; small incisions down to 2.3 mm routinely, 2.7 mm is common, certainly, far less than 3 mm," he said.
Unique material
The Collamer IOL is made of a highly biocompatible collagen and a copolymer mixture blended with benzophenone.
"The benzophenone UV absorbing property is covalently bonded," Dr. Bylsma said.
The IOL has a refractive index of 1.442. It is negatively charged and hydrophilic, meaning it needs to be kept wet. Because it has a high water content, any "dings" caused by YAG capsulotomy have been shown to disappear spontaneously. The collagen fibers of the lens also repel protein.
"It's the affinity of fibronectin for collagen that creates in the postoperative period in the eye, after implantation, a monolayer of fibronectin," Dr. Bylsma said. "This results in a very specific patina-type appearance. The surface character and the optical character of this material is unique and the first time you see it, you may think there are deposits on the lens, but it's just part of the unique feature of Collamer. The appearance goes through a transition as that fibronectin is deposited over several weeks."
According to Dr. Bylsma, the optical qualities of the lens make it special.
"It has unique optical qualities," he said. "When you look at this material you will see that it is not optically empty as some silicone and other materials are. You will be able to see the slit lamp beam through this material, just like we see it through the cornea. This IOL has collagen in it, so it's not optically empty."
The Collamer IOL features a plate-haptic design with an optic size of 6 mm and an overall length of 10.8 mm. The design aids in ease of insertion and minimizes vitreous traction.
"We have a standard plate haptic design that you simply insert, advance it and it's ready to go," Dr. Bylsma said.
According to Dr. Bylsma, one of the great benefits of Collamer is that it is malleable.
"This material is so pliable that the trailing haptic actually sits just there in the corneal lip and then simply pushing posteriorly will place the trailing haptic. We do like to perform irrigation/aspiration under the IOL to prevent a capsulorrhexis block," he said.
Study
In the study leading to Food and Drug Administration approval, the Collamer IOL was implanted in 685 eyes of 641 patients.
Visual results were good. Best corrected visual acuity of 20/40 or better was achieved in 96.2% of eyes.
To be included in the trial, patients needed to be 60 years old and undergo phacoemulsification with capsulorrhexis intact. Patients with uncontrolled glaucoma or proliferative retinopathy, with their capsules not intact or with endothelial dystrophy were excluded.
Some of the patients had existing conditions before the trial: 6.2% had macular degeneration and 5.8% had glaucoma. Small percentages of the patients had previous iritis, endothelial disease, diabetic retinopathy or previous retinal detachment.
In 95.3% of the eyes clear cornea incisions were made. In 92.5%, incision size was 3 mm or less. No sutures were used in 99%.
Low numbers of complications were reported. Two lenses were removed due to incorrect power, there was one case of endophthalmitis and two capsulorrhexis blocks. YAG capsulotomies were performed in 8% of the eyes.
For Your Information:
- Stephen Bylsma, MD, can be reached at 1414 E. Main St., Santa Maria, CA 93454; (805) 925-2637; fax: (805) 347-0033. Dr. Bylsma is a paid consultant for STAAR.
- STAAR Surgical, manufacturer of the Collamer IOL, can be reached at 1911 Walker Ave., Monrovia, CA 91016; (818) 303-7902; fax: (818) 358-9187.