The Advantages of Additive Techniques: Intrastromal Corneal Rings. by Michael D. Twa, O. D.
This refractive surgery procedure involves implanting a small plastic arch-shaped device at the outer edge of the cornea. The thickness of the Intacs used depends upon the desired refractive effect.
The main advantage of Intacs over laser vision correction procedures is the potential for adjusting or reversing the procedure. The FDA granted approval for the use of the ICRS device in the United States in 1999. There are currently designs available that correct myopia, hyperopia, and astigmatism. Some designs that will increase the range of possible correction are still under investigation. The surgical implantation of Intacs is an outpatient procedure performed under topical anesthesia.
During the procedure, the geometric center of the cornea is found, and then a 1.8mm long superior radial incision of 2/3 corneal thickness is made near the superior limbus. A vacuum-centering guide is positioned around the center of the cornea to stabilize the eye during creation of the tunnel that will hold the Intacs.
The dissector, a blunt tipped device, is guided into position at the depth of the incision. The instrument is rotated 180 degrees in each direction to make the tunnel that will hold the Intacs. The ICRS is then introduced and positioned. Sometimes a suture is used to close the original incision.
Intacs are beneficial for patients with Keratoconus. For more information click here.