Article
Modified posterior chamber phakic IOL facilitates surgery, improves outcomes
Take-home message: The implantable collamer lens features several design enhancements that make the procedure more patient- and surgeon-friendly.
Take-home message: The implantable collamer lens features several design enhancements that make the procedure more patient- and surgeon-friendly.
By Cheryl Guttman Krader; Reviewed by Erik L. Mertens, MD
Antwerp, Belgium-Design modifications have made refractive surgery with a certain posterior chamber phakic IOL easier and safer than before and enabled its use in a broader patient population, according to Erik L. Mertens, MD.
Previously, the implantable collamer lens (Visian ICL V4C CentraFLOW, STAAR Surgical) was considered by Dr. Mertens only for eyes that were not good candidates for LASIK because they had a thin cornea, dry eye, forme fruste keratoconus, high myopia, or hyperopia, he said.
“Now, almost every patient seeking correction of myopia and myopic astigmatism is suitable for the [lens],” said Dr. Mertens, medical director, Eye Center Medipolis, Antwerp, Belgium. “In 2005, the [lens] accounted for only 14% of my refractive surgeries, whereas in 2014, almost 97% of patients seeking refractive surgery were implanted with the [device].”
The lens features a 360-µm hole in the center of the optic (Aquaport) that enables more natural aqueous flow between the device and the crystalline lens while also eliminating the need for iridotomies in recipients of this phakic IOL.
There are also two similarly sized holes outside the optic-one on either side-that facilitate intraoperative removal of viscoelastic and allow aqueous to flow over a wider surface area of the crystalline lens.
“The addition of the penetrating holes eliminates the need for an extra procedure preoperatively and the potential complications that can occur with iridotomy/iridectomy,” Dr. Mertens said. “By creating more natural aqueous flow, they also reduce the risk of lens opacification.
“During follow-up that ranges up to 3 years in a series of 569 eyes with the [device] implanted, I have seen no cases of lens opacification,” he added.
Other design modifications include extension of the axis alignment markings on the toric version, which makes accurate orientation easier and enables postoperative assessment of the phakic IOL’s position, he noted.
In addition, the lens is stored in balanced salt solution rather than saline, so that it is fully hydrated.
Refractive outcomes
Results from follow-up to 1 year for 306 eyes with the lens implanted for myopia or myopic astigmatism show it provides predictable, safe, effective, and stable refractive correction. The patients, all operated on by Dr. Mertens, had a mean age of about 32 years, mean sphere of about –6 D (range –0.75 to –14.75 D), and mean cylinder of about –1 D (range 0 to –4.25 D).
Achieved spherical equivalent (SE) almost perfectly matched the attempted correction, and at postoperative follow-up visits conducted at 1, 3, 6 and 12 months, SE was plano in 96% to 99% of eyes. Mean SE was 0.02 D at 1 month and was stable at 0.01 D at all subsequent follow-up visits.
Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) at 1 year were better than preoperative BCVA. UCVA was 20/20 or better in 97.3% of eyes and 98.6% had BCVA of 20/20 or better.
Safety was excellent as well. No eyes lost BCVA and about 40% gained 1 or more lines. There were no cases with pupillary block or increased IOP.
Data from optical coherence tomography measurements of vault at the center of the ICL showed that the clearance distance decreased during the first year and then stabilized. Mean vault at 1 year was about 410 µm, but the vault was <100 µm in 23 eyes.
As the device design provides a more natural flow of aqueous, the lens can tolerate a much lower vault, Dr. Mertens said.
Erik Mertens, MD
This article was adapted from Dr. Mertens’ presentation at the 2014 meeting of the American Academy of Ophthalmology. Dr. Mertens is a consultant to Bausch + Lomb, PhysIOL, Ophtec, STAAR Surgical, and TechnolasPV.
