EVO ICL™ vs Myopic Laser Vision Correction

All content on Eyewiki is protected by copyright law and the Terms of Service. This content may not be reproduced, copied, or put into any artificial intelligence program, including large language and generative AI models, without permission from the Academy.

Article initiated by:

Brad H. Feldman, M.D., Mark Romero

All contributors:

Brad H. Feldman, M.D., Vandana Reddy, MD, Praneetha Thulasi, MD, Samera Ahmad, MD

Assigned editor:

Praneetha Thulasi, MD

Review:

Assigned status Update Pending

 by Praneetha Thulasi, MD on April 1, 2024.

add
Contributing Editors:	add

Both EVO implantable collamer lens (ICL) and myopic laser vision correction are surgical options for treating myopia, but depending on patients’ unique eyes and preferences, one approach might be a better option than the other. Both routes can greatly improve patients’ vision so that they no longer need glasses or contacts, and both are 10 to 30-minute-long outpatient bilateral procedures. However, their limits, inclusions/exclusions, and risks differ in important ways.

Introduction to EVO ICL and Myopic Laser Vision Correction

The EVO ICL has been commercially available since 2017, but received FDA approval in March 2022. The EVO ICL is designed to be inserted anterior to a patient’s crystalline lens. The EVO ICL is distinctive from other ICLs in its central port design. The central port allows for aqueous flow between the anterior and posterior chambers, decreasing the risk of pupillary block and eliminating the need for a laser peripheral iridotomy as was required by older ICL models.

There are multiple forms of laser vision correction, though the most commonly performed procedures tend to be laser assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Both procedures utilize an excimer laser to remove corneal stromal tissue and reshape the cornea to improve refractive error. LASIK utilizes the creation of a flap, minimizing the healing time associated with epithelial layer removal. PRK mechanically removes the epithelial layer prior to laser, which may prolong healing, but does eliminate the risks associated with flap creation.

Selecting patients for EVO ICL versus Myopic Laser

Both EVO ICL and myopic lasers are typically performed for patients over the age of 20-21. The EVO ICL has only been studied in patients up to 45 years old, and so patients older than that would not be candidates for insertion. Myopic laser correction can be performed on older patients.

Both procedures require patients to have demonstrate refractive stability prior to the procedure.

Corneal factors are typically most important for the selection of appropriate myopic laser correction patients. Patients must demonstrate adequate central corneal thickness to avoid the risk of post-LASIK ectasia. Screening topographies are an important part of the pre-procedural assessment as well, to assess for irregular astigmatism or existing ectatic disease. There are several contraindications to myopic laser correction, including corneal dystrophies (e.g. Fuchs, EBMD), preexisting corneal ectatic disease, retinal tears, autoimmune disease, and severe dry eye.

Risk factors for pupillary block or endothelial cell loss are most important for the selection of EVO ICL patients. Patients must have an adequate anterior chamber depth (>3.0 mm) and adequate endothelial cell density (adjusted for age). Patients must also have an angle that is open, at least grade II.

For both procedures, pregnancy and lactation are a contraindication.

RISKS of EVO ICL versus Myopic Laser Correction

Both procedures come with rare catastrophic vision threatening risks, as with any ocular procedure.

The common complication of myopic laser vision correction is dry eye. This can be temporary or permanent, mild or severe. Dry eye occurs more commonly after LASIK and has been theorized to be related to disruption/ abnormal reinnervation of the corneal nerves following flap making. Post laser ectasia is also a dreaded complication of myopic laser correction, again more common following LASIK procedures. In LASIK, flap complications can occur, such as infection, epithelial ingrowth, or diffuse lamellar keratitis. In PRK, corneal haze can occur as a complication. In both procedures, optical side effects are possible, such as glare or halos.

EVO ICLs are more commonly associated with higher order aberrations and unwanted visual effects. Due to its intraocular location, anterior subcapsular cataracts are also a risk, which is more common in older patients and more highly myopic patients. Pupillary block and glaucoma are also risks, though these have not been reported significantly in the literature. Endothelial cell loss and corneal decompensation can occur as a complication, though reportedly less than ICLs without a central port. As EVO ICLs require intraocular surgery, the standard risks of intraocular surgery also apply, including inflammation and endophthalmitis.