INTACS: Intacs are implantable intracorneal ring segments (also known as ICRS).  This is a procedure which may be helpful for patients with keratoconus or corneal optical irregularities such as ectasia after other surgeries.  Intacs were originally FDA-approved to correct low degrees of nearsightedness.  In 2004, Intacs were approved by the FDA under a Humanitarian Device Exemption for the treatment of keratoconus. Results of Intacs for keratoconus treatment have been encouraging, especially in patients unable to tolerate contact lenses or in need of a corneal transplant. 

Intacs are two small crescents of a contact lens-like material (PMMA). Unlike procedures such as LASIK, Intacs are implanted into the outer edge of the cornea so that the center of the cornea remains untouched. The insertion of Intacs causes the cornea to generally flatten. In addition, Intacs tend to decrease the irregular astigmatism found in keratoconus  Intacs can be safely removed if necessary.  In such cases, the cornea will generally return to its preoperative condition.

Corneal Topography of Keratoconus Before and After Intacs

The primary goal of Intacs in keratoconus is to make the eye again tolerant of contact lenses and to avoid corneal transplantation.  Other goals are to improve vision with glasses corrected vision as well as uncorrected vision (without glasses or contact lenses). Here at the CLEI Center for Keratoconus, we have been working with Intacs for KC for several years. Our data analyis and research over the years has let us develop enhancements to the procedure. These include creating Intacs tunnel geometries designed to best reshape your cornea, use of different Intacs sizes and positioning techniques based on your corneal analysis, and use of the new Pentacam corneal cross-section analysis to help plan your procedure. This has led to improved outcomes over the years.

THE INTACS PROCEDURE: At the beginning of the procedure, topical numbing drops are applied. A lid holder supports your lids to avoid blinking during the procedure. A channel within the cornea is then prepared, into which the Intacs will be inserted. This step is done with a laser called an Intralase or with a special intracorneal tunneling instrument. Here at the CLEI Center for Keratoconus, we generally prefer the Intralase technique, finding a more robust result in patients treated in this way. However, the ultimate selection of technique depends on your particular situation. In either case, a suction ring is placed to stabilize the eye, the channel is prepared for the Intacs, and then the Intacs are inserted. Some patients may have 2 Intacs placed, others may have only one placed depending on the individual cornea. At the end of the procedure, a stitch or contact lens bandage is placed, eyedrops are given, and a clear plastic shield is applied for protection. You will use eyedrops to avoid infection and inflammation for 1 week.

Vision begins to improve the day after the procedure but may fluctuate for several days. Most people can return to work one to two days after the procedure. During your followup examinations, we will determine if additional procedures may be beneficial. These include changing Intacs size or position, adding supplemental procedures such as CK (see below), and other techniques. Keep in mind that Intacs is not necessarily a one-time procedure... further treatment might be necessary over the months after your surgery to enhance and optimize the final result.

In brief, there are two basic types of possible side effects with Intacs. Because some patients respond and heal differently, results can vary.  In most cases, although the cornea is improved, glasses or contacts will still be necessary.  In addition, other optical side effects include haloes around lights and glare, especially at night. The other group of rarer complications may be secondary to problems with insertion of the Intacs, infection, or problems with corneal healing. In some cases, this will necessitate removal of the Intacs segments. We will discuss these possibilities in detail.

CORNEAL COLLAGEN CROSSLINKING (CXL): Collagen crosslinking using UV radiation combined with riboflavin (Vitamin B2) is an experimental procedure currently being performed in Europe and elsewhere outside the United States. It is not approved for clinical use in the United States. However, here at the CLEI Center for Keratoconus, we are participating in a formal study of CXL using the UV-X^TM Illumination System that is being conducted under FDA guidelines. We began actively treating patients in February, 2008. The goal of the study is to assess the safety and efficacy of crosslinking for the treatment of keratoconus as well as corneal ectasia after LASIK.

The primary goal of collagen crosslinking in the keratoconic patient is to strengthen and stiffen the corneal fibers in order to decrease the progression of keratoconus, and to decrease the cone steepness in some patients. The safety and efficacy of crosslinking, as yet, is unclear, although results from European studies are encouraging.

THE CROSSLINKING PROCEDURE: Anesthesia drops keep you comfortable and a lid retainer prevents you from blinking. The surface epithelial cells of the cornea are then removed and riboflavin drops are administered for 30 minutes. The riboflavin acts both to enhance the crosslinking effect and to protect the rest of the eye from the UV exposure.

The patient then looks at a UV emitting light (wavelength = 365 microns, power = 3.0 mW/cm²) for 30 additional minutes with continued administration of riboflavin drops. At the conclusion of the procedure, a soft contact lens bandage is applied.

Here at CLEI, in addition to the clinical trial, we have been actively investigating the use of corneal collagen crosslinking in animal studies to help determine new uses for it. We also are using the new Reichert Ocular Response Analyzer(ORA) to measure a number of aspects of the biomechanics of the keratoconic and post-LASIK cornea in all of our patients. This may help grade the degree of keratoconus, detect responses to treatment, and also help to predict outcomes of the different types of treatments for keratoconus.

COMBINED INTACS/CK PROCEDURE: At the CLEI Center for Keratoconus, we are working on innovative approaches to treating keratoconus. We have found that, in some cases, Intacs can be combined with the Conductive Keratoplasty (CK) procedure. CK is a collagen shrinkage procedure which can help reshape the cornea. In combination with Intacs, or performed after the Intacs suture is removed, CK may allow for better reshaping of the keratoconic cornea. In fact, we were the first to perform this combined procedure in the U.S. Although an FDA-approved procedure for the correction of farsightedness, it is important to know that CK for the treatment of keratoconus in not FDA-approved. However, it can be selected by the patient and doctor as an "off-label" procedure if appropriate. We will discuss this with you if we think you are a good candidate for Intacs/CK combined surgery.

COMBINED LASIK/INTACS FOR SEVERE NEARSIGHTEDNESS: Intacs, in selected cases, may be used as a supplemental procedure to LASIK or LASEK/PRK for the treatment of severe nearsightedness. This may be particularly useful in patients with thinner corneas which prevent the safe treatment of the full amount of nearsighedness with the laser alone.