When the punch is received it will be in a sterile tray sealed with a Tyvek lid. The sealed tray is housed in a cardboard carton along with printed instructions and a gentian violet marking pen. The tray contains a vacuum syringe, the cutting block and top blade assembly, and a seating ring.
The instructions below will refer to the components as identified in the photo.
Before clinical use, the surgeon should thoroughly understand all aspects of the surgical procedure and the use of the Vacuum Donor Cornea Punch. The Barron Vacuum Donor Cornea Punch® is packaged in a hermetically sealed tray that has been gas sterilized with ethylene oxide. It is a disposable unit designed for single-use and should not be re-sterilized or reused. The punch has been carefully checked before packaging and is ready for use when it is received. The Barron Vacuum Donor Cornea Punch® should be used only by a licensed physician who is familiar with corneal transplant surgery and with the use of this instrument. The following instructions do not include all the procedural steps required to perform corneal transplant surgery.
- The size of the punch blade is stamped on both the top of the punch top and the side of the cutting block as indicated in the photo at the right (the stamped numbers are circled in red). Verify the blade diameter and remove the elastic silicone band from the instrument.
- The parts are held together with an elastic silicone band that should be removed after the components are taken out of the tray. The punch top and cutting block are separated by a ring that prevents the blade from contacting the block during shipment. While holding the cutting block with one hand, use the other hand to pull the punch top straight upward, turn it over, and place it on a sterile tray. Discard the white blade protector ring that is used to separate the punch top from the cutting block.
- To mark the four quadrants on the epithelial side of the donor cornea, first open the sterile pouch that contains the surgical marking pen that comes with the punch assembly. Then place the tip of the pen into each of the four holes in the well of the cutting block. Rotate (twist) the pen until the sides of each hole are evenly coated with gentian violet ink.
- Push in the plunger of the syringe all the way and hold. (It is helpful to have a surgical assistant do this).
- Place the donor cornea, endothelial surface up, in the well of the cutting block. Center the donor cornea in the well with fine-toothed forceps.
- Place the cutting block on a solid, flat surface. Insert the four steel guideposts of the seating ring housing into the corresponding holes in each corner of the cutting block and press down gently.
- Release the plunger of the syringe abruptly.
- While holding the cutting block with one hand, pull the seating ring housing upward with the other hand and discard it.
- With the cutting block on a solid, flat surface, insert the four steel guideposts of the punch top into the corresponding holes in each corner of the cutting block. Place the thumb directly over the trephine blade and press down firmly with enough pressure to cut through the cornea.
- While holding the cutting block with one hand, pull the punch top upward with the other hand to remove the trephine blade.
- Grasp the scleral rim with fine-toothed forceps and remove the rim from the cutting block. This releases the vacuum and leaves the donor cornea button in the well of the cutting block.
- Leave the cutting block with the donor corneal button undisturbed until the button is to be used. Prolonged contact of the button with the inked holes in the well of the cutting block enhances the epithelial marks. Desiccation may be prevented by the application of a few drops of the corneal storage medium on the button.