no longer makes sense to replace the entire thickness of the cornea. Melles Þrst described a technique of posterior lamellar keratoplasty in 1999 in which he advocated the transplantation of posterior corneal tissue for endothelial dysfunction [7]. In his technique, the recipient and donor corneas were manually dissected at 80Ð90% stromal depth, excising the posterior recipient stroma and endothelium with a trephine and scissors, and inserting a donor button through a scleral incision [7]. He advocated the procedure in cases of endothelial dysfunction, citing that Òless surgical time, less risk of intraoperative complications, less risk of high astigmatism, faster visual recovery, less frequent follow-up visits for selective suture removal, elimination of suture-induced vascularization toward the graft, and less risk of wound dehiscenceÓ [7]. He later described a technique in 2004 for excision of only the Descemet membrane and the endothelial cell layer without incisions being made in the posterior corneal stroma [8]. This technique would enable a quicker and less traumatic preparation of the recipient stromal bed [8]. The stroma is usually not affected in cornea endothelial dysfunction and thus it is not necessary to involve the stroma in the dissection. Melles thus described the technique of DescemetÕs stripping [8]. DescemetÕs stripping endothelial keratoplasty has replaced full thickness cornea transplantation as the procedure of choice for cornea endothelial dysfunction. The indications for DSEK have expanded to include those listed above as well as corneal edema associated with iridocorneal endothelial syndrome (ICE) and to restore clarity to a failed prior penetrating graft [9].

In 2005, 4.5% of the donor corneas transplanted in the US were used for endothelial keratoplasty [9]. In 2006, this number jumped to 45% of tissue requests [9]. DSEK patients regain vision sooner, have minimal to

no refractive shift postoperatively, and have an eye that is structurally more sound [9]. It is for these reasons that cornea transplant surgeons are now performing DSEK as opposed to full-thickness keratoplasty.

4.2.2Descemet’s Stripping Endothelial Keratoplasty Surgical Technique

Instrument list

1.Trephines 8.0, 8.5, 9.0 mm

2.Moria CB microkeratome (if not using precut tissue)

3.300 and 350micrometer heads for microkeratome

4.ArtiÞcial anterior chamber (if performing manual donor dissection)

5.DORC dissection blades (three curved blades)

6.Paracentesis blade

7.2.75 Millimeter keratome (for clear cornea incision)

8.Crescent blade (for scleral tunnel incision)

9.Reverse sinskey hook

10.DescemetÕs stripping instrument (Fig. 4.15)

11.Irrigation/Aspiration handpiece and Phaco unit

12.Inserting forceps (Kelman-Mcpherson, Goosey, Charlie)

13.Tuberculin syringes (one with air + cannula, one with BSS + cannula, one with air + 27or 30-gauge needle)

14.Needle holder

15.Tying forceps

The donor cornea is prepared Þrst, followed by surgery on the recipient. It is the authorÕs preference to use precut tissue from an eyebank. This eliminates the step of donor preparation.