Drug-dispensing contact lenses a reality

May 9, 2012

By Geoffrey G. Goodfellow, O.D., and Dominick M. Maino, O.D.

Eye care providers are readily familiar with the vision and cosmetic benefits that contact lenses afford over spectacles. Most of these clinicians are also aware of the more medical applications of such devices in the form of bandage contact lenses and orthokeratology. However, another important medical use for contact lenses is nearing reality – pharmaceutical dispensing.

Such drug-dispensing contact lenses may make the traditional eye drop a thing of the past.

Researchers have developed methods for lenses to deliver drug doses evenly for anywhere between one and 30 days depending on the type of lens material used.

This may translate into drug delivery that is significantly more effective than eyedrops.

Studies from Auburn University estimate drug delivery via contact lenses is 100 times better than regular eyedrops.

Applications of such lenses include continual medication delivery for conditions such as glaucoma, eye inflammation, infections, and allergies.

Traditional drops have their problems. The drug is washed away by tears, can sit around inside the cul-de-sac unabsorbed, or have trouble permeating the corneal epithelial membrane. It is estimated 1 percent or less of an administered dose actually reaches the part of the eye needing treatment.

For these reasons, traditional drops must be delivered in frequent doses and at relatively high concentrations, which can result in adverse effects.

The need for frequent dosing can also lead to poor patient compliance and diminished treatment efficacy.

There are also patients, particularly the elderly, who may have difficulty instilling drops without assistance.

A drug-dispensing contact lens may be the solution to many of these problems.
Because such lenses are capable of correcting or not correcting refractive error, they can be an option for almost any patient.

The lenses are truly a new technology; they aren’t simply traditional contact lenses soaked in medication. The science behind this breakthrough is accomplished in several different ways:

  • Modifying the interaction of the contact lens polymers, or
  • Interjecting colloidal particles (nanoparticles, liposomes, etc.) into the lens, or
  • Molecularly imprinting the lens with template-shaped cavities that act similarly to the “lock and key” method that enzymes use to bind to substrate, or
  • Using ion ligands to bind drug molecules.

It will likely take several more years for drug-dispensing lenses to navigate through human testing and regulatory hurdles and become readily available to clinicians, but they are definitely coming.

The ophthalmic drug market is nearly $20 billion per year, which mainly consists of eyedrops and ointments. Drug-dispensing contact lenses will revolutionize the entire industry of ocular medication.

For optometrists to provide this technology to our patients, it is necessary that we have the legislated authority to handle these medical devices.

State laws that permit diagnostic and therapeutic eyedrops may or may not contain wording that automatically permits the use of drug-dispensing contact lenses.

In-office dispensing of pharmaceuticals or contact lenses that contain pharmaceuticals may also trigger some legal conflicts.

The AOA and its state affiliates must continue to proactively support the profession’s advancement as new technologies become available for our patients.

States considering legislation should seek help and additional information from the AOA State Government Relations Committee.

Dr. Maino is a professor of pediatrics and binocular vision at the Illinois College of Optometry (ICO) and a recipient of the Leonardo da Vinci Award of Excellence in Medicine. He can be contacted at dmaino@ico.edu. Dr. Goodfellow is an associate professor of optometry at ICO and the college’s assistant dean for curriculum and assessment. He can be contacted at ggoodfel@ico.edu.

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