Home > Eye Institute > Corneal Rings

Corneal rings (Keravision INTACS)
Keravision INTACS (Integrated Tactical Communications System) correct mild nearsightedness without laser surgery.

What are INTACS?
INTACS are two tiny half rings designed to permanently correct vision when placed within the eye. They are made of a special biocompatible plastic that has been safely used in contact lenses and cataract surgery for nearly 50 years. They are very small. Inside the cornea, they are practically invisible - and they cannot be felt. INTACS corneal ring segments are the result of nearly a decade of clinical research and have been available in other countries for several years. INTACS corneal ring segments are a medical device designed for the reduction or elimination of myopia from -1.00 to -3.00 diopters.

Correcting nearsightedness
To appreciate the procedure for placing INTACS, it is best to begin with an understanding of how INTACS work with the corneal anatomy to correct mild nearsightedness. Envision the cornea as arcs of fiber extending from edge to edge. If a spacer element is inserted between those fibers, effectively pushing them apart, then the arc must flatten to accommodate the inserted element. The INTACS segments within the cornea act as spacer elements that produce a slight overall flattening. This flattening affects refraction. What is unique about this flattening, compared to photorefractive keratectomy (PRK) or laser in-situ keratomileusis (LASIK), is that INTACS shorten the corneal cord length and produce flattening across the entire cornea.

How do they work?
Simply, INTACS gently change the shape of your cornea to correct your vision. In the nearsighted eye, the curve of the cornea is too steep. Light rays entering the eye are bent too much and are focused improperly. As a result, things far away appear blurry. INTACS change the shape of the cornea, allowing the light rays to focus correctly.

Who qualifies for INTACS?
You do, if:

• Your prescription for eyeglasses or contacts is between -1.0 to-3.0 diopters, with no more than 1.0 diopter of astigmatism
• You have healthy eyes, free from disease or injuries
• You have had stable vision for one year
• You are at least 21 years of age

For more information about the Eye Institute, please call 603.663.2020 or e-mail eyeinstitute@cmc-nh.org.