Intrastromal Corneal Rings (ICRs) -- Intacs™
On April 12, 1999 the U.S. FDA approved the use of KeraVision Intacs™, the first removable or exchangeable , non-laser method designed specifically for correcting low levels of nearsightedness.
Intacs corneal ring segments are the product of years of research and development. They provide an alternative to eyeglasses and contact lenses as well as surgical procedures that permanently alter the eye by cutting or removing tissue from the central cornea. Because no eye tissue is removed during the Intacs procedure, the procedure is reversible, and may be later updated when even better technologies become available.
Intacs are two tiny half-ring lenses. To get an idea of how small they are, imagine a contact lens where the center part has been removed and only the very outer edge remains; then imagine this ring divided into two equal halves; Intacs are that small! They are made of a special biocompatible plastic that has been safely used in contact lenses and cataract surgery for nearly 50 years. When placed in the periphery of the cornea, they are practically invisible.
In the nearsighted eye, the curve of the cornea is too steep. Light rays entering the eye are bent too much and are focused in front of the retina instead of on it. As a result, things far away appear blurry. Intacs effectively change the shape of the cornea, allowing the light rays to focus on the retina. Intacs are placed in the outer edge, leaving the central optical zone intact.
If you are considering Intacs, the following information will provide you with a good introduction to the procedure. For more detailed information about how this procedure may help you, we recommend that you consult ophthalmologists with experience in this procedure.
What are the most common benefits of this surgery?
What will happen at the initial consultation?
How is Intacs surgery performed?
How long does the surgery take?
Where will the procedure be performed?
How much pain is there?
What can I expect after surgery?
What is the recovery period like?
Ideal Candidate
Other important information
Risks and Limitations
Intacs are a safe and effective means to correcting mild nearsightedness. (-1.00 to -3.00 diapoters with no astigmatism.) Intacs are FDA-approved, unlike some laser procedures. Intacs offer an immediate improvement in vision. Intacs provide excellent results. In U.S. clinical studies, 97% of patients saw 20/40 or better with Intacs, 74% saw 20/20 or better, and 53% saw 20/16 or better. Tissue is not removed from the central optical zone
What will happen at the initial consultation?
During the initial consultation, your surgeon will talk with you about the changes that you will experience. He/she will explain the different options available to you, the procedure itself, and its risks and limitations. He/she will also explain the kind of anesthesia required, surgical facility, and costs.
Your physician will begin with a complete medical history. He/she may also give you specific instructions preparing for surgery, including guidelines for eating and drinking, smoking, and taking or avoiding vitamins, supplements and medications.
If you wear contact lenses, you will need to stop wearing them at some period before you go in for your initial consultation or examination in which additional visits may be necessary. The time period is different for hard and soft lenses so you should ask your doctor about this before you go in for your first screening.
Take this opportunity to ask all the questions you have about the surgery. Ask for, and follow up on, patient references. Learning everything you can about your options, risks and benefits is the key to making an informed decision. See Questions to ask your doctor below (make this a link).
How is Intacs surgery performed?
You will probably be given a mild oral sedative, as well as eye drops to numb the eye. A tiny opening, less than 2 mm, is made near the upper edge of the cornea beneath the eyelid. Precise, specially calibrated instruments are used to create two small tunnels in the periphery of the cornea. The corneal tissue is separated, but not cut. Intacs are inserted through the opening so that they rest in these tunnels, between the layers of corneal tissue Once in place, the two arcs flatten the cornea so that light rays can properly focus on the retina.
How long does the surgery take?
It takes approximately 15 to 30 minutes to place Intacs in your eye. The total procedure for one eye, including preparation time, is usually less than one hour.
Where will the procedure be performed?
The procedure is performed in a surgical suite. The patient sits in a surgical chair, which is reclined into a horizontal position.
How much pain is there?
Most people report that they feel no pain during the procedure itself. Some people can feel the presence of the ring segments for a few days after surgery, but this foreign body sensation disappears as the eye heals. There also may be some soreness on the surface of the eye due to instruments used during ring segment positioning. After the eye heals from the procedure.
What can I expect after surgery?
Visual improvement is apparent soon after the ring segments have been inserted. Most healing takes place within the first week, with full stabilization achieved by one month. Patients can usually continue with regular activities within two or three days of the surgery.
Possible side effects include light sensitivity, decreased clarity in dim light, glare or haloes from lights at night, blurry or double vision and fluctuating distance vision. These side effects generally disappear as the eye heals.
If the visual result is not satisfactory, the ring segments can be removed and eye will most likely return to it's original shape before surgery. Replacing ring segments with those of a different thickness is also an option to change the visual result, or to correct the vision again if eyes change after the original surgery.
What is the recovery period like?
Because the central portion of the cornea is left untouched, visual recovery is fast, and the majority of patients notice significantly improved vision the first day after surgery. During the FDA monitored clinical studies, about 30% of patients who had Intacs had one line of improvement in their best vision after insertion.
Intacs insertion is performed on an out-patient basis. The patient is able to go home the same day. Most people resume normal activities within two or three days.
What is the long-term outcome like for most people?
In U.S. clinical studies, 97% of patients saw 20/40 or better with Intacs; 74% saw 20/20 or better-the standard for good vision, and 53% saw 20/16 or better-a level that exceeds the standard for good vision. Your doctor can discuss your situation with you so that you may better understand what your potential results might be.
Typically, patients no longer depend on glasses for correction of their distance vision. Some patients may still wear glasses for reasons specific to their situation. For example, Intacs do not correct presbyopia, so you may still need reading glasses. It is not recommended that a contact lens be worn on an eye that has Intacs.
Ideal Candidate: In general, the best candidates for Intacs are: Knowledgeable about the procedure In good physical and psychological health Willing to follow directions for optimal results Wanting to improve low-level myopia or nearsightedness Realistic in their expectations and understands all risks and benefits. Perspective patient needs to have a pupil size less than 7.00mm Perspective patient should be nearsighted with a prescription between -1.00 and -3.00 diapoters with little or no astigmatism.
Other important information
Intacs are currently available for people with mild myopia (nearsightedness) who have no more than 1.00 diopter of astigmatism. The best way to find out if you are a candidate for the procedure is to schedule an appointment with your eye physician so that he/she can evaluate your vision.
You may qualify for Intacs, if:
Your prescription for eyeglasses or contacts is between -1.00 and -3.00 diopters, with no more than 1.00 diopter of astigmatism You have healthy eyes, free from disease or injuries You have had stable vision for at least one year You are at least 21 years of age
You should not have Intacs placed if:
You have large pupils. You have autoimmune or immunodeficiency diseases (lupus, rheumatoid arthritis or AIDS, for example) You are pregnant or nursing You have known conditions of the eye that may increase the possibility of future problems You are taking prescription medications that may affect corneal healing or your vision. Your doctor will review your general medical history with you and will evaluate your eyes for any conditions that might suggest you should not have Intacs. It is important to advise your doctor if you have had a Herpes infection in your eyes or if you have insulin-dependent diabetes or other medical conditions that affect wound healing. You should also bring a list of any prescription and over-the-counter medicines that you take.
As with any refractive surgical procedure, there are some risks and possible complications. Clinical studies in the U.S. showed that infection, which is a risk with any surgical procedure, occurred in 0.2% Intacs procedures. This is treatable with medication, and no adverse effects usually result.
Other rare complications included: overcorrection, reduction in central corneal sensation, difficulty with night vision, undercorrection, induced astigmatism, blurry vision, double vision, corneal blood vessels, halos, glare, fluctuating distance vision and a reduction of 2 or more lines of best corrected vision. If the results of the procedure are not satisfactory, Intacs may be removed or replaced. Ask your doctor will discuss the potential risks and benefits in detail with you.
