According to Mark Packer, MD, FACS, observations include key data points and clinical implications.
Since its introduction in the 1990s, the implantable Collamer lens (ICL) has gained worldwide acceptance and been safely implanted in over 2 million eyes in 75 countries. The United States, however, has been slower to integrate the ICL into its refractive armamentarium.
But this is now changing, primarily because of the availability of the EVO Visian ICL with its central port design, which eliminates the requirement for preoperative peripheral iridotomy (PI). With the recent FDA approval of this model, we can expect growth in the United States to match the growth that has occurred globally over the last decade.
As medical monitor of the US FDA EVO ICL clinical trial, I would like to share key findings from several published studies that demonstrate the long-term safety and effectiveness of this lens. These data provide extensive evidence to help support surgeons who are considering offering this refractive surgery option that spares the cornea and helps eliminate spectacles and/or contact lens dependence.
Given that EVO ICLs have not been available in the United States until recently, many cataract and refractive surgeons are unfamiliar with how these lenses differ from earlier ICL models. The EVO ICL is a single-piece, posterior chamber phakic refractive IOL designed with a central port, which eliminates the need for a PI.
The purpose of the 360-μm opening in the center of the lens is to facilitate aqueous flow from the posterior chamber to the anterior chamber. This central port maintains the normal physiology of the anterior segment of the eye and maintains a protective cushion of aqueous between the ICL and the crystalline lens. As with earlier models of the ICL, EVO is indicated for phakic patients 21 to 45 years of age to correct or reduce myopia with up to 4D of astigmatism with spherical equivalent ranging from –3D to –20D with a true anterior chamber depth of 3 mm or greater. It is contraindicated in patients with anterior chamber angle less than Shaffer grade III.
Decade of data
In 2018, a comprehensive review of data from peer-reviewed scientific literature on the safety and effectiveness of EVO ICLs was published in Clinical Ophthalmology.1 Based on findings from 12 preclinical and 55 clinical studies, the results of the review showed that EVO ICLs achieve excellent refractive predictability and stability, and high levels of postoperative uncorrected distance visual acuity (UDVA), with an average UDVA of 20/19. In 27 peer-reviewed papers with effectiveness data from retrospective and prospective case studies that included 1905 eyes with a weighted average follow-up of 12.5 months, the weighted average UDVA was –0.02 logMAR.1
More recently, in February 2021, data from a prospective study by Martínez-Plaza et al provided an analysis of EVO lenses and showed that more than one-third of the 36 eyes in the study gained 1 line of best spectacle-corrected VA (BSCVA ) and none of the eyes lost even 1 line of BSCVA at the 6-month postoperative visit.2 Using the Quality of Life Impact Refractive Correction questionnaire, patients reported significant improvements in quality of vision and quality of life.2
Safety data suggest that these lenses reduce the rate of anterior subcapsular cataract (ASC) and pupillary block compared with earlier ICL models. In 38 peer-reviewed papers with safety data from retrospective and prospective studies for the EVO ICL, which included 4196 eyes with up to 5 years of follow-up, no patient developed a visually significant ASC and only 1 eye experienced pupillary block (due to retained viscoelastic).1
Furthermore, Kamiya et al performed a peer-reviewed comparison of optical quality and intraocular light scattering after posterior chamber phakic IOLs with and without the central port. Data showed that the port does not significantly alter the optical performance of the EVO lens compared with older ICLs without the central port.3
An additive procedure
Because no tissue is removed during the procedure, implantation of EVO ICLs is not limited by corneal thickness.4 Given that the surgery does not alter the shape of the cornea, selection of IOL power for future cataract surgery is unaffected by ICL implantation, unlike corneal refractive surgical procedures such as LASIK.5 In addition to making more implant options available for the surgeon and patient, keeping the cornea intact eliminates the potential for corneal ectasia and reduces the potential for dry eye.1 EVO ICLs are made of Collamer, a collagen-containing biocompatible material that is bonded with UV-absorbing chromophore into a poly-HEMA based copolymer. This combination offers UV protection and minimizes inflammation.6,7
As the medical monitor of the US clinical study of the EVO family of lenses, and a veteran cataract and refractive surgeon, I am gratified that patients in the United States now have access to this procedure, which allows “optically superb correction of relatively high degrees of ametropia.”8 As increasing numbers of US refractive surgeons add EVO to their armamentarium, an organic flow of word-of-mouth referrals will likely follow. Patients will come to expect refractive surgery practices to offer EVO ICLs as a solution for myopia, and surgeons will need to be prepared to respond to this growing demand.
Mark Packer, MD, FACS
Packer is president of Packer Research Associates in Boulder, Colorado. He serves as a medical monitor for STAAR Surgical.
Packer M. The implantable collamer lens with a central port: review of the literature. Clin Ophthalmol.2018;12:2427-2438.