Implantable Contacts: Hope for Extreme Myopia

If you're extremely nearsighted, you've probably dreamed of life without glasses or contacts. You watch through smudged lenses or cloudy contacts as your less visually challenged friends get LASIK surgery and throw away their spectacles. Now there's a new alternative to LASIK. You may be a candidate for implantable contacts (ICLs).

Implantable contacts have been available in Europe for more than a decade. In Europe, they have been used to treat two conditions:

• Nearsightedness or myopia (inability to see clearly at a distance)
• Astigmatism (irregular curvature of the eye).

In 2004, the U.S. Food and Drug Administration (FDA) approved the first of two brands of implantable contacts to treat moderate to extreme nearsightedness. Studies are underway in the U.S. to evaluate implantable contacts for astigmatism.

Types of Lenses and How They Work

These are the two types of FDA-approved implantable lenses:

• The Verisyse Phakic Intraocular Lens (IOL) for people aged 21 and older
• The Visian Implantable Collamer Lens (ICL) for people aged 21 to 45

The Verisyse lens is implanted in front of and attached to the iris. The Visian lens is placed behind the iris in front of the natural lens of the eye. As with eyeglasses and contacts, the lens works by bending or refracting light rays to bring them to sharp focus on the retina.

Stanford University School of Medicine was one of 10 sites in the U.S. to evaluate implantable contacts. Edward E. Manche, MD, assistant professor of ophthalmology, participated in that study.

"The advantage of the Visian lens is that it's a small, foldable lens inserted through a small incision with one suture or no suture. The Verisyse lens requires a larger incision and longer recovery. Both work well. We don't know which will become the dominant lens."

In clinical trials, both brands corrected vision well. With the Visian lens, 95% of patients had 20/40 or better vision, the level needed to obtain a driver's license, and 59% had 20/20 or better after three years. With the Verisyse lens, 92% had 20/40 or better vision, and 44% had 20/20 or better after three years.

Candidates for Implantable Contacts

In young people who are nearsighted, vision typically worsens with age. For that reason, candidates for implantable contacts must be healthy adults whose vision is stable. That means vision has not required a prescription change of more than .5 diopters in the past year.

Implantable contacts are generally suitable for people whose vision correction ranges from -3 to -20 diopters and with astigmatism of less than 2.5 diopters. By comparison, LASIK refractive surgery is recommended for people whose vision correction ranges from -5 to -14 diopters and less than -5.0 diopters of astigmatism.