Techniques for posterior lamellar keratoplasty through a scleral incision

Purpose. To describe several techniques for posterior lamellar keratoplasty through a scleral incision, for management of corneal endothelial disorders like pseudophacic bullous keratopathy and Fuchs' endothelial dystrophy, and to report the mid-term clinical results.Methods. Three techniques have been developed to perform a posterior lamellar keratoplasty procedure through a scleral incision, i.e. to replace the posterior corneal layers while leaving the anterior corneal surface intact and without the use of corneal sutures. In the first technique, a 9.0 mm scleral incision is made to accommodate an intracorneal trephine and spoon-shaped glide to insert a 7.5 mm donor posterior lamellar disc into the anterior chamber. In the second technique, the procedure is performed through a 5.0 mm scleral tunnel incision using microscissors and by folding a 8.5 mm donor posterior disc prior to insertion. In the third technique, a 4.0 mm tunnel incision is made to perform a descemetorhexis in the host cornea, i.e. Descemet's membrane is selectively excised from the recipient eye, and a 9.0 mm donor Descemet's membrane is inserted. In eyes with a minimal post-operative follow-up of 3-5 years (n=16), we documented the best spectacle corrected visual acuity (BSCVA), keratometry reading, endothelial cell counts,and clinical events.Results. In all cases,the graft adhered to the recipient posterior cornea without suture fixation. In patients without concomitant ocular disease, BSCVA was 0.7-1.0 in all eyes. The astigmatism averaged 2.1 +/- 0.7 D, endothelial cell counts averaged 2126 +/- 529 cells/mm(2) at 6 months, 1839 +/- 473 cells/mm(2) at 12 months, 1418 +/- 434 cells/mm(2) at 24 months, and 1137 +/- 420, cells/mm(2) at 36 months. In two patients, an iridocorneal adhesiolysis was performed within days after the procedure. In one patient, residual viscoelastic adherence was present at the donor-to-recipient interface, and a penetrating keratoplasty was performed 1 month postoperation. One patient developed significant interface haze, requiring a penetrating keratoplasty 13 months after the first surgery.Conclusion. Posterior lamellar keratoplasty can be an effective surgical technique to manage corneal endothelial disorders. An improved visual acuity can be obtained within the first weeks after surgery, and the visual perfomance of the graft is stable up to 5 years postoperation.</p

Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

PURPOSE: To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. METHODS: In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy was performed to evaluate the en, dothelial cell density. For each postoperative time inter, val, the mean endothelial cell loss relative to the preoperative value was calculated. RESULTS: Mean postoperative endothelial cell loss averaged 283 cells/mm(2) (+/- 293) at 6 months, 335 cells/mm(2) (+/- 309) at 12 months, and 421 cells/mm(2) (+/- 316) at 24 months. Estimate relative endothelial cell density losses obtained by mixed model analysis of variance were 11.1%, 2.0%, and 1.2%, respectively, each time compared with its previous measurement point. Second order comparisons showed that the loss within the first 6 months was significantly higher than after 6 months. CONCLUSION: In deep anterior lamellar keratoplasty, the recipient corneal endothelium showed a small initial drop in endothelial cell density followed by a physiologic rate of cell loss. Cell survival after lamellar keratoplasty may be expected to be better when compared with that following penetrating keratoplasty. (C) 2004 by Elsevier Inc. All rights reserved

Endothelial cell density after posterior lamellar keratoplasty (Melles techniques): 3 years follow-up

PURPOSE: To report the midterm endothelial cell density measurements after posterior lamellar keratoplasty (Melles techniques). DESIGN: Cohort study. METHODS: Fifteen consecutive eyes of 15 patients in whom a posterior lamellar keratoplasty procedure was performed for pseudophakic bullous keratopathy or Fuchs' endothelial dystrophy were evaluated. In 11 corneas the donor tissue was inserted through a 9.0-mm sclerocorneal pocket incision (technique A); in four cases the donor was folded and inserted through a 5.0-mm incision (technique B). Specular microscopy was performed at 6, 12, 24, and 36 months after surgery, to measure the endothelial cell density. RESULTS: Mean postoperative endothelial cell density averaged 2,126 cells/mm(2) (+/-548) at 6 months, 1,859 cells/mm(2) (+/-477) at 12 months, 1,385 cells/mm(2) (+/-451) at 24 months, and 1,047 cells/mm(2) (+/-425) at 36 months. CONCLUSION: In posterior lamellar keratoplasty, the donor corneal endothelium showed a decrease in cell density similar to that after conventional full thickness penetrating keratoplasty. (C) 2004 by Elsevier Inc. All rights reserved