Long-Term Dehydrated Donor Lamella Survival in Anterior Keratoplasty: Keratocyte Migration and Repopulation of Corneal Stroma.

PURPOSE: The aim of this study was to investigate the ability of host keratocytes to colonize the donor lamella transplanted without viable cells (dehydrated) in Descemetic (deep anterior lamellar keratoplasty) and in pre-Descemetic keratoplasty (excimer laser-assisted lamellar keratoplasty). METHOD: A total of 17 eyes (8 deep anterior lamellar keratoplasties and 9 excimer laser-assisted lamellar keratoplasties) were included in this observational retrospective study; patients underwent ophthalmic examinations, and histological staining was performed ex vivo on the graft in cases of failure. RESULTS: In Descemetic keratoplasty, the long-term survival of the graft is compromised with the central corneal thickness decreasing; corneal pachymetry and in vivo and ex vivo keratocyte densities are significantly reduced (pachymetric reduction of -86 µm in the apex and -87 µm in the thinnest point; density cell reduction of 72% at a depth of 100 µm, 62% at a depth of 250 µm, and -66% at a depth of 400 µm). In pre-Descemetic keratoplasty, clinical complications, reduction of central thickness, or alterations of keratocyte density were not observed. CONCLUSIONS: In Descemetic keratoplasty, the migration of the host peripheral keratocytes does not seem enough to repopulate the donor graft, whereas in pre-Descemetic keratoplasty, long-term survival of the graft is good. Keratocyte repopulation was observed only by extensive contact between the donor and host parenchyma.

Excimer laser mushroom penetrating keratoplasty: new technique.

PURPOSE: To evaluate retrospectively the outcomes of 15 consecutive mushroom-shaped penetrating keratoplasties performed by using excimer laser for both the recipient bed and the fresh donor corneas. METHODS: Fifteen eyes of 14 patients who underwent excimer laser mushroom-shaped penetrating keratoplasty from October 13, 2010, to October 14, 2011, were included in our retrospective study. Eight were men and 6 were women, with a mean age of 31.45 ± 6.52 (range 27-65) years. Eleven (73.3%) had postinfective central deep corneal scar; 4 (26.7%) had severe keratoconus with Descemet opacity. RESULTS: The mean follow-up was 11.9 ± 2.7 months. The mean preoperative best-corrected visual acuity (BCVA) was 0.15 ± 0.16; the postoperative BCVA was 0.69 ± 0.24 after 12 months with a mean refractive astigmatism of 1.8 ± 1.1 D. The mean preoperative endothelial cell count of the donor corneas was 2297.0 ± 189.7 cells/mm²; after 12 months, it was 1906.5 ± 165.8 with a decrease of 17.0%. No intraoperative complications occurred. CONCLUSIONS: Our results showed that excimer laser mushroom penetrating keratoplasty is safe. Furthermore, it does not appear to influence the visual outcomes of the penetrating keratoplasty surgery. This technique is useful for those who use an excimer laser.

The effects of different preservation processes on the total protein and growth factor content in a new biological product developed from human amniotic membrane.

The aim of this work is to quantify the total protein and growth factors content in a tissue-suspension obtained from processed human amniotic membrane (hAM). hAM was collected, frozen, freeze dried, powdered and sterilized by γ-irradiation. At each step of the process, samples were characterized for the total protein amounts by a Bradford protein assay and for the growth factor concentrations by ELISA test of the tissue suspensions. Frozen-hAM samples show higher release of total proteins and specific growth factors in the tissue suspension in comparison with freeze-dried hAM. We observed that even if the protein extraction is hindered once the tissue is dried, the powdering process allows a greater release in the tissue suspension of total proteins and growth factors after tissue re-solubilization in comparison with only the freeze-drying process (+91 ± 13% for EGF, +16 ± 4% for HGF, +11 ± 5% for FGF, +16 ± 9% for TGF-ß1), and a greater release of EGF (85 ± 10%) in comparison with only the freezing process, because proteins become much readily solubilized in the solution. According with these results, we describe a protocol to obtain a new sterile biological product from hAM tissue, with well-known effects of thermal, mechanical and physical processes on the total protein and grow factors contents.

Deep anterior lamellar keratoplasty with dehydrated, 4 °C-stored, and rehydrated lenticules.

PURPOSE: To retrospectively evaluate the outcomes of 124 consecutive deep anterior lamellar keratoplasties (DALK) performed by using dehydrated, 4 °C stored, and rehydrated lenticules. METHODS: A total of 124 eyes of 109 patients, which had undergone DALK from August 11, 2000, to December 13, 2007, were included in our retrospective study; 88 cases were male and 36 female, with a mean age of 39.45±15.52 years (range 6-85). A total of 109 (87.9%) had keratoconus, 7 (5.6%) had deep or superficial corneal scar, 3 (2.4%) had epikeratophakia, 3 (2.4%) had pellucid degeneration, 1 (0.8%) a malignant pterygium, and 1 (0.8%) had a severe alkali burn. All the patients underwent ophthalmic examinations, including best-corrected visual acuity (BCVA), central ultrasound pachymetry, computerized topography, specular microscope endothelial cell count, and confocal microscopy. RESULTS: The mean follow-up was 23.9±3.4 months. The mean preoperative BCVA was 0.16±0.18; the postoperative BCVA was 0.68±0.20 after 2 years. The mean preoperative central corneal thickness (CCT) was 439.4±10.5 µm; after 2 years, it was 532.1±9.7 µm. The mean preoperative endothelial cell count (ECC) was 2301.3±180.2 cells/mm2; after 2 years it was 1986.0±169.5 with a decrease of 13.7%. Baring of Descemet membrane (DM) during DALK was achieved in 112 (90.32%) eyes; 4 eyes (3.26%) had a large perforation of the DM with consequent PK. Small intraoperative perforation of DM during DALK occurred in 18 cases (14.52%). CONCLUSIONS: The results showed that the method of preservation and distribution of dehydrated, 4 °C stored, and rehydrated lenticules is safe, cheap, and simple. Furthermore, it does not appear to influence the outcomes of the DALK surgery.

Enzymatic descemetic lamellar keratoplasty: pilot study.

PURPOSE: This was a pilot study to evaluate the efficacy of a new surgical technique of descemetic anterior lamellar keratoplasty (DALK) with the help of enzymatic hyaluronidase solution. METHODS: We selected 10 patients, 6 male and 4 female, with surgical keratoconus, with a mean age of 45+/-16 years (range 29-61), with best-corrected visual acuity (BCVA)