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DSAEK in Asian Eyes. Jodhbir S Mehta, Donald Tan The Authors have a financial Interest in the E ndoglide patent/royalty. Purpose.
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DSAEK in Asian Eyes JodhbirS Mehta, Donald Tan The Authors have a financial Interest in the Endoglide patent/royalty
Purpose 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.
Purpose We initiated a DSAEK surgical program at the Singapore National Eye Centre, with all cases performed between March 2006 and December 2009. 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 AC13 and higher vitreous pressure, which created difficulties with unfolding the donor in the AC
Methods • We prospectively reviewed all patients who underwent DSAEK in Singapore National Eye Center (SNEC) between 2006 and December 2009. • Data included patient demographics, ophthalmic history, and indications and details of surgery, preoperative and postoperative Snellen visual acuity (VA) with refraction. • Outcome measures were • Final VA, • Donor Dislocation • Graft failure - defined as an irreversible loss of central graft clarity from any cause, irrespective of the level of VA
Surgical Techniques 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 • Following Graft insertion, all eyes underwent air tamponade for 8 minutes. The surgical procedure was identical in all cases apart from the donor insertion.,
ResultsComparison of Taco and Glide Techniques: Day 1 appearance: Taco technique Glide technique We immediately noted a clear difference in graft clarity
Our clinical results of 250 consecutive cases of DSAEK First 20 cases: Folding technique: 5 primary graft failures (25%) 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) Pre-op We performed 20 cases of DSAEK, with the folding technique, before switching completely to the glide technique for our next 230 cases All our primary graft failures successfully regrafted with the Sheets Glide method Post-op Dislocation rates: Folding: 1 dislocation (5%) Glide: 2 dislocations (0.86%) (reported rates are 8% to 50%)
Our Visual Results % of eyes 1 week 1 month Pre-op 3 months Preop VA Mean VA 6/12 6 months Post op VA Current BCVA (mean follow-up of 12 months): - 70% attained 20/40 or better - 33% attained 20/30 or better
Complications – Late 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 postopendophthalmitis following repeat DSAEK supposed entry of fungal infection from reopening of corneal venting incisions 1 reactivation of CMV endothelitis - masquerades as rejection
Discussion 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 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 In order to improve on our results we have developed a custom built insertion device
Stable AC throughout:closed eye system Advantages of the EndoGlide • 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
Singapore National Eye Centre Conclusion • 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