Micro-thin Prescription Inserts INTACS™ are two small arcs of medical plastic that a surgeon places into the mid-periphery of the corneal stroma. Once in place, the inserts cause a slight stretching of the cornea and a subtle flattening of the corneal curvature. The change in curvature varies with the thickness of the inserts. To place the inserts, the surgeon must first create a small incision in the periphery of the A tunnel is created between layers of the stroma. The tunnel is made outside the central optical zone of the eye, but still within the cornea. The surgeon chooses the appropriate ring thickness (the thicker the ring, the more flattening — and the more vision correction achieved).

The tunnels are then closed up with sutures if necessary. Once placed, the inserts can be removed or replaced by the surgeon if the patient’s vision needs change. Under U.S. clinical study since 1991, KeraVision INTACS™ received FDA approval for the correction of -1.00 to -3.00 D of myopia with no more than 1.00 D of astigmatism in April 1999.