Jodhbir S Mehta, Donald Tan The Authors have a financial Interest in the Endoglide patent/royalty

Descemet’s stripping automated endothelial keratoplasty (DSAEK) is form of endothelial keratoplasty procedure in which descemet’s membrane and diseased endothelial tissue is replaced with a healthy partial thickness posterior donor lenticule. Descemet’s stripping automated endothelial keratoplasty (DSAEK) is form of endothelial keratoplasty procedure in which descemet’s membrane and diseased endothelial tissue is replaced with a healthy partial thickness posterior donor lenticule. DSAEK is rapidly increasing in popularity as an alternative to conventional penetrating keratoplasty (PK) due to inherent advantages of small incision, closed-globe, sutureless surgery, resulting in enhanced structural integrity and rapid visual recovery related to minimal refractive change and the lack of graft sutures. DSAEK is rapidly increasing in popularity as an alternative to conventional penetrating keratoplasty (PK) due to inherent advantages of small incision, closed-globe, sutureless surgery, resulting in enhanced structural integrity and rapid visual recovery related to minimal refractive change and the lack of graft sutures.

We initiated a DSAEK surgical program at the Singapore National Eye Centre, with all cases performed between March 2006 and December We initiated a DSAEK surgical program at the Singapore National Eye Centre, with all cases performed between March 2006 and December A total of 20 procedures were performed on Asian eyes. PGF occurred following 5 procedures in 4 eyes, PGF rate of 25%. A total of 20 procedures were performed on Asian eyes. PGF occurred following 5 procedures in 4 eyes, PGF rate of 25%. The high rate of PGF prompted us to modify the folding donor insertion to a pull-through glide technique. This suited the smaller Asian eye with shallower AC 13 and higher vitreous pressure, which created difficulties with unfolding the donor in the AC The high rate of PGF prompted us to modify the folding donor insertion to a pull-through glide technique. This suited the smaller Asian eye with shallower AC 13 and higher vitreous pressure, which created difficulties with unfolding the donor in the AC

We prospectively reviewed all patients who underwent DSAEK in Singapore National Eye Center (SNEC) between 2006 and December We prospectively reviewed all patients who underwent DSAEK in Singapore National Eye Center (SNEC) between 2006 and December Data included patient demographics, ophthalmic history, and indications and details of surgery, preoperative and postoperative Snellen visual acuity (VA) with refraction. Data included patient demographics, ophthalmic history, and indications and details of surgery, preoperative and postoperative Snellen visual acuity (VA) with refraction. Outcome measures were Outcome measures were Final VA, Final VA, Donor Dislocation Donor Dislocation Graft failure - defined as an irreversible loss of central graft clarity from any cause, irrespective of the level of VA Graft failure - defined as an irreversible loss of central graft clarity from any cause, irrespective of the level of VA

a) Taco folding DSAEK insertion (n=20). This was performed using a previously described technique. Essentially the graft was folded with a 40:60 under-fold and inserted with goosey forceps with the 60% fold facing superiorly. b) Glide Insertion Technique (n = 230). The Donor cornea was inserted on a bed of dispersive viscoelastic (Viscoat) placed on an anterior chamber Sheet Glide. All donor grafts were prepared with an ALTK system by the surgeon at the time of surgery All donor grafts were prepared with an ALTK system by the surgeon at the time of surgery Following Graft insertion, all eyes underwent air tamponade for 8 minutes. The surgical procedure was identical in all cases apart from the donor insertion., Following Graft insertion, all eyes underwent air tamponade for 8 minutes. The surgical procedure was identical in all cases apart from the donor insertion.,

We immediately noted a clear difference in graft clarity Glide techniqueTaco technique

Our clinical results of 250 consecutive cases of DSAEK Pre-op Post-op Dislocation rates: Folding: 1 dislocation (5%) Glide: 2 dislocations (0.86%) (reported rates are 8% to 50%) First 20 cases: Folding technique: 5 primary graft failures (25%) We performed 20 cases of DSAEK, with the folding technique, before switching completely to the glide technique for our next 230 cases Next 230 cases: Glide technique: 1 primary graft failure (0.43%) (our PK primary graft failure rate = 1.7%) Postoperative endothelial cell counts: Folding: 61.4% cell loss Glide:29.8% cell loss (US studies show 35% cell loss) All our primary graft failures successfully regrafted with the Sheets Glide method

Our Visual Results Pre-op 6 months 3 months 1 month1 week % of eyes Current BCVA (mean follow-up of 12 months): - 70% attained 20/40 or better - 33% attained 20/30 or better Preop VA Mean VA 6/12 Post op VA

19 cases of raised IOP – 7 Trabeculectomy 3 cases of graft rejection (1.2% - lower than PK?) 3 cases of late endothelial graft failure – all folding cases 1 case of postop endophthalmitis following repeat DSAEK supposed entry of fungal infection from reopening of corneal venting incisions 1 reactivation of CMV endothelitis - masquerades as rejection

The majority of published series of DSAEK patients are in Caucasian Eyes that are biometrically larger than Chinese Eyes The majority of published series of DSAEK patients are in Caucasian Eyes that are biometrically larger than Chinese Eyes Our initial results using the folding technique resulted in an unacceptable rate of PGF. This was mainly due to problems with unfolding of the donor tissue. Following conversion to a Glide Technique we were able to reduce our PGF rate to less than the rate for PK in our centre. Our initial results using the folding technique resulted in an unacceptable rate of PGF. This was mainly due to problems with unfolding of the donor tissue. Following conversion to a Glide Technique we were able to reduce our PGF rate to less than the rate for PK in our centre. Our visual acuity results and early complications are comparable with those reported in Caucasian patients Our visual acuity results and early complications are comparable with those reported in Caucasian patients Our mean ECC loss at one year is 68% with folding and 33% with glide insertion Our mean ECC loss at one year is 68% with folding and 33% with glide insertion In order to improve on our results we have developed a custom built insertion device In order to improve on our results we have developed a custom built insertion device

Stable AC throughout: closed eye system Stable AC throughout: closed eye system Minimal endothelial touch/damage: - “double coiling” of donor - no contact with wound - Endoforceps grips stromal edge only Full donor control at all times - Endoforceps holds donor in the AC even after EndoGlide is withdrawn

DSAEK is rapidly becoming the procedure of choice for corneal endothelial disease DSAEK is rapidly becoming the procedure of choice for corneal endothelial disease Newer developments in surgical techniques are improving surgical outcomes that will allow the excellent surgical results to be available worldwide Newer developments in surgical techniques are improving surgical outcomes that will allow the excellent surgical results to be available worldwide Singapore National Eye Centre