Date: Mar 25, 2015 Source: Helio.com (
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Corneal opacity and scarring secondary to a wide spectrum of infectious and inflammatory corneal diseases are a major cause of global blindness. Worldwide, about 45 million people are blind, and corneal blindness is the second leading cause, with about 4.9 million people having bilateral corneal blindness.
Corneal blindness with a healthy posterior segment is often surgically reversible, and keratoprosthesis may be one of the avenues to achieve this goal, especially in cases of high-risk graft failure. With advances in keratoprosthetic devices, there is a move toward using these devices as a primary transplantation procedure in select patients. However, currently popular commercially available keratoprosthetic devices require a donor cornea, and demand exceeds supply, thus limiting the outreach of corneal transplantation to those who need the procedure.
Some of the favorable uses of the foldable keratoprosthesis described in this article include the elimination of the need for a donor cornea because the device is housed within the recipient cornea and does not violate the interior of the globe. Further, it does not enter into or alter the anterior chamber anatomy, and hence, there is usually no secondary glaucoma associated with this keratoprosthesis. Continued research is required to further improve the interactions between human corneal tissue and the prosthetic materials for longer lasting residence within the recipient cornea, without tissue melt or extrusion of the device over time.
In this column, Drs. Shiuey and Vargas describe the KeraKlear foldable keratoprosthesis (KeraMed), the surgical implantation technique and early results. This device is not FDA approved in the U.S.
Thomas "TJ" John, MD
OSN Surgical Maneuvers Editor
The KeraKlear keratoprosthesis is foldable and has a 4-mm central optic and an overall diameter of 7 mm (Figure 1). Unlike other commercially available artificial corneas, the KeraKlear is implanted using a non-penetrating technique and does not require donor tissue for implantation.
Surgical technique
The KeraKlear artificial cornea is implanted into the cornea by using a femtosecond laser to create a uniform lamellar pocket within the cornea and to create a trephination incision. After preparation of the cornea, the KeraKlear is then inserted into the corneal pocket through the anterior opening in the cornea using non-toothed forceps. The rim of the device is then tucked into the pocket recesses. (See video for surgical technique at http://video.healio.com/video/KeraKlear- XT-implantation;Ophthalmology.) Optionally, four sutures can be placed in each quadrant. This procedure requires removal of approximately 5% of the corneal tissue volume to implant (Figure 2). Postoperatively, these patients wear a bandage contact lens and receive prophylactic antibiotic eye drops.
