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.