I have the older instrumentarium to implant the Ferrara ring/Keraring devices. Am I supposed to change it for Cornealring implantation purposes?
No. The only thing to do is a minor adjustment to your surgical procedure. The tunnel zone marker for the Ferrara Ring/Keraring prints an inner 4.4 mm and an outer 5.6 mm circumference at the cornea. Under the traditional procedure for these rings, the spatula has to insert precisely between these two circumferences to make the tunnel (see Figure below). For the Corneal Ring, the surgeon has to have in mind that this device has a slightly larger diameter, as compared to the old ones (Corneal Ring has a 4.7 mm inner diameter, compared to the 4.4 mm of the former triangular-shaped segments). Therefore, the spatula has to insert below the outer circumference marked on the cornea, moving away from the inner circumference (see Figure below). For better control of the spatula direction, it is recommended to hold the eye tight with a Kremer’s forceps fixed at the periphery of the annulus conjunctivae. The specific instrumentarium for the Corneal Ring implantation is already available, thus av
