contact lens business
Coming Attractions
Remarkable new contact lenses are on the horizon.
By Christopher Kent, Senior Associate Editor

Contact lens technology continues to evolve at a dizzying pace. Here's a brief overview of three new developments that could have a significant impact on your practice within a few years.

Correcting Higher-Order Aberrations

Optical Connection Inc., developer of the DefinitionAC line of aberration-control contact lenses, has acquired the rights to a system that produces customized, wavefront-based contact lenses. These "WaveTouch" lenses can correct each patient's unique higher-order aberrations, without the risks involved in ablative surgery.

To produce lenses for a patient, wavefront readings are taken through a trial contact lens placed on the eye. This makes it possible to take into account rotation or decentration of the lens during wear, so the wavefront-based correction is correctly positioned on the lens to center over the visual axis. (Rota-tion is discouraged by a system similar to that used in toric lenses.) The wavefront data is linked to a high-speed manufacturing system that imprints the appropriate correction on a flexible, hydrophilic lens.

A spokesperson for the company says the WaveTouch lenses may redefine the vision standard to 20/10 or better, improve contrast two to five times, and minimize night vision problems.

The lenses will be produced in multipacks for frequent replacement; they should be available in the second half of this year.

Anuj Chauhan, M.D., of the University of Florida in Gainesville, is developing a new type of contact lens that will slowly deliver medication directly into the eye. (Eye drops allow up to 95% of a medication to enter the blood stream through the sinuses, potentially triggering side-effects such as cardiovascular problems, allergic reactions or impotence.) Previously, all attempts to design such lenses have failed.

Dr. Chauhan's team has found a way to encapsulate drugs in particles about 50 nanometers wide that are mixed into the contact lens matrix during manufacture. (The lenses themselves can be made of a soft hydrogel like that in use today, which should keep the cost down.) The particles are too small to scatter light, so they don't cloud the finished lenses.

In addition to treating diseases like glaucoma, these lenses could be an excellent way to treat or prevent dry eye. Antibiotics could even be incorporated into the lenses to prevent bacterial infection. (The lenses will probably need to be replaced every 2 weeks.)

Dr. Chauhan expects to begin animal studies within the next year and predicts the lens will be in clinical use within 10 years.

Monitoring Glucose Levels

Sanford Asher, a professor of chemistry at the University of Pittsburgh, is developing a material that changes color to indicate the level of glucose in a surrounding liquid. Because the glucose level in our tears correlates with blood glucose level, placing this material in a section of a contact lens would allow a diabetic to monitor his blood sugar level simply by looking in a mirror.

The material is a hydrogel made up of long polymer chains. Glucose binds to receptors in the chains, changing the spacing between them and altering how light diffracts through the material. High concentrations of glucose produce a purple color; normal levels give the material a green tint; low levels produce a reddish color. A patient would simply compare the color seen in the mirror to a chart to estimate blood sugar level.

In addition to resolving design and functionality issues, Professor Asher hopes that research will refine our understanding of the correlation between blood sugar level and tear glucose level. If that relationship is well-defined and predictable, this method will serve as a reliable, noninvasive method for monitoring blood glucose level.

Professor Asher says he expects it will be several years before such a contact lens becomes available.