There’s a new alternative to LASIK in the United States. In March of 2022, the FDA approved STAAR Surgical’s EVO/EVO+ VISIAN Implantable Collamer Lens (ICL) and Toric Implantable Collamer Lens (TICL).
There’s a new alternative to LASIK in the United States: an alternative that preserves the cornea and crystalline lens1, that doesn’t exacerbate dry eye2, increase the risk of ectasia3 or complicate IOL power calculations for future cataract surgery4; an alternative that provides rapid visual recovery and is reversible.1
That alternative is the EVO ICL.
On March 25, 2022, FDA approved STAAR Surgical’s EVO/EVO+ VISIAN Implantable Collamer Lens (ICL) and Toric Implantable Collamer Lens (TICL)5.
Refractive surgeons in the US were already familiar with the indications for these lenses, because they are the same as the indications for the MICL, approved in 2005, and the TICL, approved in 2018. The advance is the innovative 360-micron diameter central port in the EVO/EVO+ sphere and toric ICL lenses that facilitates the physiologic flow of aqueous humor, eliminating the need for peripheral iridotomies prior to implantation.
Outside the US, EVO lenses have been commercially available since 2011 and EVO+ lenses since 2016. Both EVO and EVO+ lenses are marketed in over 75 countries (EVO+ features a larger optic size and is otherwise similar). Where these lens models are available, now including the US, patients require fewer office visits and procedures prior to starting a new life without dependence on contacts or glasses.
Eliminating the need for peripheral iridotomies streamlines same day, bilateral implantation of EVO lenses (“In the United States, it is common and accepted practice to perform same day bilateral sequential surgery.”6). However, there is more to the central port than enhanced workflow and patient convenience, as important as these are: “Safety data suggest reduced rates of anterior subcapsular cataract and pupillary block compared with earlier models.”7 The physiologic flow of aqueous through the central port appears to help protect the crystalline lens and keep the angle open. Globally, these safety advantages have driven increased utilization of EVO lenses for the correction of mild to moderate myopia (outside the US, EVO is available in powers starting at -0.5 D).8
EVO and EVO+ lenses are available in four sizes which vary in overall diameter: 12.1, 12.6, 13.2 and 13.7 mm. The size is an important factor in the distance that results between the EVO lens and the crystalline lens, a distance known as vault.
STAAR Surgical provides an on-line system for calculating the most appropriate size based on the corneal white-to-white (WTW) distance and the anterior chamber depth (ACD).
Authors have described various other methods of measuring the eye and calculating the best fit lens, including, most notably, ultrasound measurements of the diameter of the ciliary sulcus and optical coherence tomography measurements of crystalline lens rise and the angle-to-angle distance. A recent meta-analysis concluded that “no methodology has proven superior in terms of the predictability of vault to the use of WTW and ACD, which remains the most popular and best-studied technique.”9
Irrespective of the method, variability of vault occurs based on the interaction of the EVO lens and the posterior chamber of the eye: “The degree of variation in vault is independent of sizing methodology and is related to the interaction of the lens implant with the anatomy and physiology of the posterior chamber.”7
Fortunately, the resulting range of vault is well tolerated: we know this because the incidence of adverse events is very small.For example, anterior subcapsular (ASC) cataract has been previously associated with low vault; however, “11 publications including data on a total of 617 eyes with a weighted average follow-up of 13 months reported a 0.49% incidence of asymptomatic ASC opacities.”7
The incidence of visually significant cataract was 0.0%. Pupillary block and angle closure glaucoma have been associated with high vault; however, 38 peer-reviewed publications with safety data from retrospective or prospective series including information on 4, 196 eyes with weighted average follow up of 14.0 months revealed only a single case (0.04%), which was due to blockage of the central port by “viscoelastic and inflammatory debris.”10 These data demonstrate that a wide range of vault is well tolerated.
The effectiveness of the EVO ICL lenses is “optically superb.”11 The average efficacy index, uncorrected postoperative visual acuity divided by preoperative corrected visual acuity, is 1.04, and the average uncorrected visual acuity is better than 20/20; 90.8% of eyes are within 0.50 D and 98.7% are withing 1.00 D of target.7 These results are strikingly similar to those for LASIK12 and SMILE.13
The advantages of EVO make it very appealing to doctors and patients.EVO offers a straightforward, bilateral, single-day, in-office procedure that does not permanently alter the eye yet provides superb correction of a wide range of myopia and astigmatism.With over one million lenses implanted worldwide, 99.4% of patients say they would have the procedure again.7 At the end of the day, we must admit, that little hole in the lens is a big deal.
Disclosure: Mark Packer serves as Medical Monitor for STAAR Surgical.