"Implantation of this phakic IOL (PIOL) carries risks associated with an intraocular procedure, and there are still sizing issues with this lens, but [we hope] they will be addressed with new imaging systems, said Dr. Katsanevaki, head, refractive department, Orasis Eye Center, Athens, Greece.
"Concerns also remain about cataract formation, but the risk has been successfully reduced thanks to evolution in lens design," Dr. Katsanevaki said. "Furthermore, if cataract develops, it can be managed safely and effectively with removal of the PIOL and phacoemulsification. This seems an acceptable tradeoff for the benefits of the PIOL in treating [patients with high ametropia]."
The Visian ICL is available in myopic and hyperopic models in several different lengths ranging from 11.5 to 13 mm for custom fitting. It was approved by the FDA in 2005 for correction of myopia from –3 to –15 D and for reducing myopia from –15 to –20 D with 2.5 D astigmatism at the spectacle plane. A hyperopic model is also available with a dioptric range from +3 to +21 D, and outside the United States, a myopic toric version is available in power ranges of –3 to –20 D for sphere and 1 to 6 D of cylinder.
Compared with the first models of the Visian ICL, the V4 version features a larger optic, can be implanted through a smaller incision size, has a better loading and injector system, and most importantly, has better vaulting over the crystalline lens that has reduced the risk of cataract. Subsequently, the V4B model was introduced that has two full-thickness holes by the optical zone for enabling aqueous flow within the posterior chamber in order to reduce cataractogenesis further. Now, the Visian ICL design has evolved to model V4C, which features a central hole that may eliminate the need for intraoperative iridectomy and therefore make the surgery easier and faster, said Dr. Katsanevaki.
Reviewing clinical outcomes data, Dr. Katsanevaki cited the 3-year results from the FDA clinical trial of the Visian ICL that showed excellent uncorrected visual acuity (UCVA), refractive predictability, and contrast sensitivity under mesopic illumination with and without glare.
"With this lens, the quality of vision is often better after implantation than before," Dr. Katsanevaki said.
She also referenced prospective controlled studies in the literature showing that results for safety, efficacy, predictability, and stability were better in patients with the Visian ICL implanted than in comparator groups undergoing LASIK or PRK.
Dr. Katsanevaki said that the toric version of the ICL has expanded the pool of potential candidates for PIOL implantation, including patients with keratoconus, and she reported data from 24 keratoconic eyes with the toric ICL implanted. Compared with conventional eyes, outcomes in the keratoconic group showed similarly excellent refractive predictability and UCVA. For the keratoconus group, postop UCVA at 1, 3, 6, and 12 months after surgery was within 1 line of preoperative best spectacle-corrected visual acuity (BSCVA) in about 80% of eyes and was better than preop BSCVA in about 50% of eyes.
"These are great results in a challenging group of patients, but eyes have to be carefully selected and should have reasonably good BSCVA preoperatively," she said.