Ami Halvorson, OD

PCLI—Portland, OR

From the EDITOR   Implantable collamer lenses are placed behind the iris, in front of the crystalline lens, to correct myopia with or without astigmatism. In this issue, my colleague Ashley Bailey provides an overview of this vision correction option that has been widely used in other countries over the past 30 years, with more than three million lenses distributed worldwide.

Over three decades, implantable collamer lenses (ICLs) have emerged as a transformative solution in vision correction. Also known as implantable contact lenses, they are a viable alternative to corrective eyewear and corneal refractive procedures like LASIK and PRK. ICLs are crafted from a biocompatible material and surgically positioned within the eye to correct myopia (-3D to -20D) and astigmatism (1 to 4D).

Understanding ICLs

ICLs are semi-permanently implanted within the eye to provide consistent and stable vision correction. The micro-thin collamer is made from a UV radiation-absorbing polymer that contains hydroxyethyl methacrylate (HEMA) and porcine collagen. This composition ensures the lens is flexible and biocompatible, allowing it to harmoniously integrate with the eye’s natural structures without causing discomfort or adverse reactions. The collamer material also minimizes inflammation  and flare.

ICLs can address the visual needs of a range of individuals, including those who may not be suitable candidates for laser vision correction due to thin corneas, high refractive errors, or dry eyes.

Benefits

1. Precise Vision

ICLs deliver precision correction that closely mimics natural sight without distorted peripheral vision, reduced contrast sensitivity, bothersome glare, or night vision changes.

2. Customization

Modern ICLs are designed to fit perfectly within the eye, enhancing visual acuity. They are also customized to each eye’s shape, size, and refractive error.

3. Stability and Predictability

Outcomes are stable and predictable since ICLs do not alter the corneal shape. They do not change over time, so vision correction remains consistent unless there are changes in the eye or natural lens.

4. Reversibility

If necessary, ICLs can be removed or exchanged to accommodate changes in vision, technological advancements, and cataract surgery.

5. UV Protection

The collamer material in ICLs blocks harmful UV rays, enhancing eye comfort and long-term ocular health.

6. Convenience

ICLs integrate seamlessly into daily life, offering the convenience of clear vision without regular maintenance or dependence on external vision aids. Activities like swimming, sports, and outdoor pursuits can be enjoyed without the limitations of glasses or contacts.

Candidates

Ideal candidates typically include individuals aged 21 to 45 with stable prescriptions seeking long-term vision correction without the constraints of glasses or contacts. They should have adequate anterior chamber depth and endothelial cell count to ensure safe and effective lens placement. Overall eye health will also be evaluated to determine candidacy. For patients with prescriptions outside the correctable diopter range, ICLs can be combined with LASIK or PRK.

The Procedure

ICL surgery is minimally invasive and performed under topical or local anesthesia. The steps include:

• Pre-op evaluation

A thorough eye exam to assess eye health, refractive error, and suitability for ICLs.

• Lens Calculation

Precise measurements of the eye’s dimensions are taken to customize the ICL size and power for optimal correction. Measurements include anterior chamber depth, endothelial cell density, and horizontal white-to-white.

• Surgical Placement

The folded ICL is inserted through a clear corneal incision and then positioned behind the iris in front of the anterior capsule of the natural crystalline lens.

• Post-op Care

 Patients are closely monitored to ensure proper lens placement and IOP control.

Potential Risks

While ICLs are safe and effective for most candidates, it is essential to understand the potential risks and considerations associated with the procedure. Some factors to consider include:

• Cataract Formation

Although rare, there is a slight risk of cataracts developing as a result of ICL implantation or at an earlier stage in life than they would have otherwise. Regular monitoring by an eye care professional is crucial to detect any changes in the crystalline lens over time.

• Intraocular Pressure

In some cases, ICLs may affect IOP. Patients with pre-existing glaucoma or other conditions affecting eye pressure should discuss these risks with their provider.

• Endothelial Cell Health

The procedure has minimal impact on the corneal endothelium, but patients should have adequate endothelial cell density to support long-term lens function and ocular health.

Advancements

Advancements in ICL technology have continued to improve safety, predictability, and visual outcomes. The most recent ICL (EVO Visian ICL) features a central hole that allows aqueous to flow through the lens. This eliminates the need for peripheral iridotomies prior to surgery. Studies show this reduces the rate of anterior subcapsular cataracts and pupillary block when compared to earlier models.

Over the years, other innovations in lens design and materials, enhanced sizing algorithms, and refined surgical techniques have improved patient satisfaction and reduced post-op complications.

Conclusion

The newest ICL represents a significant advancement in vision correction technology, offering a versatile solution for individuals seeking high-quality visual outcomes without the constraints of traditional eyewear. With their precision, reversibility, and natural visual quality, ICLs are an excellent option for refractive error correction among qualified candidates.