BACKGROUNDThe limiting factor to corneal transplantation is the availability of donors. Research has suggested that xenogenic acellular corneal scaffolds (XACS) may be a possible alternative to transplantation. This study aimed to investigate the viability of performing lamellar corneal transplantation (LCT) in rabbits using canine XACS.

METHODSFresh dog corneas were decellularized by serial digestion, and LCT was performed on rabbit eyes using xenogeneic decellularized corneal matrix. Cellular and morphological changes were observed by slit-lamp, light, and scanning electron microscopy at 7, 30 and 90 days postoperatively. Immunocytochemical staining for specific markers such as keratin 3, vimentin and MUC5AC, was used to identify cells in the graft.

RESULTSDecellularized xenogenic corneal matrix remained transparent for about 1-month after LCT. The recipient cells were able to survive and proliferate into the grafts. Three months after transplantation, grafts had merged with host tissue, and graft epithelialization and vascularization had occurred. Corneal nerve fibers were able to grow into the graft in rabbits transplanted with XACS.

CONCLUSIONSXenogenic acellular corneal scaffolds can maintain the transparency of corneal grafts about 1-month and permit growth of cells and nerve fibers, and is, therefore, a potential substitute or carrier for a replacement cornea.

Animals ; Cornea ; surgery ; Corneal Stroma ; surgery ; Corneal Transplantation ; methods ; Dogs ; Microscopy, Confocal ; Rabbits ; Tissue Engineering

A myxoma is a benign tumor found in the heart and in various soft tissues; however, a corneal myxoma is rare. A mucinous mass of unknown etiology was observed on the left cornea of a 32-year-old male patient. We performed deep anterior lamellar keratoplasty using acellular corneal tissue and concurrent amniotic membrane transplantation. Hematoxylin and eosin staining revealed vacuolation of the parenchyma and myxoid change in the corneal tissue that occurred in the anterior half of the corneal parenchyma. We identified a myxoid stroma by Alcian blue staining and observed collagen fibers with denatured stroma by Masson trichrome staining. The patient's visual acuity improved from light perception to 20 / 200, and the intraocular pressure remained within the normal range for one year after surgery. The transplanted cornea survived successfully with well-maintained transparency, and recurrence was not observed one year after surgery.
Adult ; *Cornea ; Corneal Stroma/cytology/*transplantation ; Corneal Transplantation/*methods ; Eye Neoplasms/diagnosis/*surgery ; Humans ; Male ; Myxoma/diagnosis/*surgery

A myxoma is a benign tumor found in the heart and in various soft tissues; however, a corneal myxoma is rare. A mucinous mass of unknown etiology was observed on the left cornea of a 32-year-old male patient. We performed deep anterior lamellar keratoplasty using acellular corneal tissue and concurrent amniotic membrane transplantation. Hematoxylin and eosin staining revealed vacuolation of the parenchyma and myxoid change in the corneal tissue that occurred in the anterior half of the corneal parenchyma. We identified a myxoid stroma by Alcian blue staining and observed collagen fibers with denatured stroma by Masson trichrome staining. The patient's visual acuity improved from light perception to 20 / 200, and the intraocular pressure remained within the normal range for one year after surgery. The transplanted cornea survived successfully with well-maintained transparency, and recurrence was not observed one year after surgery.
Adult ; *Cornea ; Corneal Stroma/cytology/*transplantation ; Corneal Transplantation/*methods ; Eye Neoplasms/diagnosis/*surgery ; Humans ; Male ; Myxoma/diagnosis/*surgery

The purpose of this study is to assess the efficacy of the multi-zone cross-cylinder method as compared with the single method for astigmatism correction using LASIK. This prospective study enrolled 40 patients (52 eyes) who underwent the cross-cylinder method using LASIK, and 52 patients (60 eyes) who underwent the single method using LASIK: all patients were given a diagnosis of complex myopic astigmatism from the department of ophthalmology of this hospital between January 2002 and July 2003. Preoperatively, the mean spherical equivalent refraction was .3.85 +/- 1.13 D in the cross-cylinder group and .4.05 +/-1.20 D in the single method group (p = 0.23). The mean cylinder was .2.05 +/-1.58 D in the cross-cylinder group and .1.95 +/-1.12 D in the single method group (p = 0.31). 6 months after treatment the results were a mean spherical equivalent refraction of .0.26 +/-0.30 D in the crosscylinder group and -0.34 +/-0.35 D in the single method group (p = 0.13). The mean cylinder was .0.38 +/-0.29 D in the cross-cylinder group and .0.45 +/-0.30 D in the single method group (p = 0.096). There were no statistically significant differences between the two groups. The mean BCVA was not different from mean preoperative BCVA in both groups (i.e., 0.98 +/-0.10, 0.96 +/-0.25, p = 0.86). Postoperatively, patient complications that included night halo, glare and corneal haze were not noted in either group. In conclusion, the results of cross-cylinder method are no different from the single method for the correction of a complex astigmatism. In the future, studies will have to be conducted to assess the efficacy of the cross-cylinder method in consideration of those factors that can affect the postoperative outcome.
Adult ; Astigmatism/*surgery ; Corneal Stroma/surgery ; Humans ; Keratomileusis, Laser In Situ/*methods ; Myopia/*surgery ; Postoperative Complications ; Prospective Studies

PURPOSE: To compare corneal flaps created in rabbits with a 60 kHz femtosecond (FS) laser using different levels of raster energy and to measure early inflammation, corneal stromal cell death, and late postoperative adhesion strength. METHODS: Sixty rabbits were divided into three groups of 20 each. A flap 110 micrometer thick and 9.0 mm in diameter was made in one eye of each rabbit at raster energies of 0.7 microJ, 1.1 microJ, and 2.4 microJ. Histopathological evaluation for inflammation and apoptosis using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed at 4 and 24 hours after flap creation. The adhesion strength of the flaps was measured with a tension meter at 1 and 3 months. RESULTS: Twenty four hours after flap creation, the 2.4 microJ group had more inflammatory and CD11b-positive cells than the 0.7 and 1.1 microJ groups. The number of TUNEL-positive cells increased with raster energy at 4 and 24 hours. The grams of force (gf) needed to detach the flaps at 3 months was significantly higher in 2.4 microJ group (170 gf) than in 0.7 microJ group (97.5 gf) and 1.1 microJ group (100 gf, p = 0.03). CONCLUSIONS: Using raster energy lower than 1.1 microJ to make a flap with a 60 kHz FS laser decreases inflammatory cell infiltration and corneal stromal cell death in the central cornea but may result in a weaker flap than using higher raster energy (2.4 microJ).
Animals ; Cell Death ; Corneal Stroma/*pathology/*surgery ; Keratitis/*pathology/*prevention & control ; Laser Therapy/*methods ; Male ; Models, Animal ; Rabbits ; *Surgical Flaps ; Tissue Adhesions/pathology/surgery

PURPOSE: To compare corneal flaps created in rabbits with a 60 kHz femtosecond (FS) laser using different levels of raster energy and to measure early inflammation, corneal stromal cell death, and late postoperative adhesion strength. METHODS: Sixty rabbits were divided into three groups of 20 each. A flap 110 micrometer thick and 9.0 mm in diameter was made in one eye of each rabbit at raster energies of 0.7 microJ, 1.1 microJ, and 2.4 microJ. Histopathological evaluation for inflammation and apoptosis using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed at 4 and 24 hours after flap creation. The adhesion strength of the flaps was measured with a tension meter at 1 and 3 months. RESULTS: Twenty four hours after flap creation, the 2.4 microJ group had more inflammatory and CD11b-positive cells than the 0.7 and 1.1 microJ groups. The number of TUNEL-positive cells increased with raster energy at 4 and 24 hours. The grams of force (gf) needed to detach the flaps at 3 months was significantly higher in 2.4 microJ group (170 gf) than in 0.7 microJ group (97.5 gf) and 1.1 microJ group (100 gf, p = 0.03). CONCLUSIONS: Using raster energy lower than 1.1 microJ to make a flap with a 60 kHz FS laser decreases inflammatory cell infiltration and corneal stromal cell death in the central cornea but may result in a weaker flap than using higher raster energy (2.4 microJ).
Animals ; Cell Death ; Corneal Stroma/*pathology/*surgery ; Keratitis/*pathology/*prevention & control ; Laser Therapy/*methods ; Male ; Models, Animal ; Rabbits ; *Surgical Flaps ; Tissue Adhesions/pathology/surgery

OBJECTIVETo construct artificial rabbit corneas with autologous skin epidermal stem cells and allogenic stromal cells in vitro and promote healing of corneal wounds.

METHODSSkin epidermal stem cells were isolated from autologous skin samples. Keratocytes were isolated from newborn cornea biopsies. The cells were combined with acellular porcine corneal stroma scaffold to construct artificial corneas. Then the constructed artificial corneas were used to repair severe vision loss caused by complete loss of corneal epithelial stem cells.

RESULTSCultured skin epidermal stem cells and keratocytes were in good growth conditions. Cultured artificial corneas consisted of multiplayer epithelial cells growing on stroma equivalent consisting of stromal matrix with incorporated keratocytes. The in vitro constructed artificial corneas were histologically similar to normal rabbit corneas. Three months after transplantation, the cornea wounds were healed and the rabbit cornea became transparent.

CONCLUSIONThe artificial corneas were constructed successfully in vitro and can be used to repair severe vision loss caused by complete loss of corneal epithelial stem cells.

Animals ; Corneal Stroma ; cytology ; Epidermis ; cytology ; Eye Injuries ; surgery ; Female ; Limbus Corneae ; injuries ; surgery ; Male ; Prostheses and Implants ; Rabbits ; Stem Cells ; cytology ; Tissue Engineering ; methods

PURPOSE: To analyze healing changes of corneal wounds of different corneal incision sizes with or without stromal hydration in cataract surgery using anterior segment optical coherence tomography. METHODS: Cataract surgeries were performed by a single surgeon and 2.2- and 2.8-mm corneal incisions were made using a diamond blade (ME-759; Meyco, Biel-Bienne, Swiss). Patients were divided into four groups according to incision size (2.2 and 2.8 mm), and with/without stromal hydration. Fifteen eyes were assigned to each group and incision wounds were measured using anterior segment optical coherence tomography at 2 hours, 1 day, 1 week, 1 month, and 3 months postoperatively. Corneal thickness, incision length and incision angle were measured and existence of epithelial, endothelial gaping and Descemet's membrane detachment was evaluated. RESULTS: Incision thickness was greater in the group with stromal hydration than in the group without on operation day (p < 0.05). Stromal hydration exerted greater influence in the 2.2-mm incision group than in the 2.8-mm incision group. Corneal thickness decreased more rapidly in the stromal hydration group than in the group with no hydration (p = 0.022). Endothelial gaping was greater in the 2.2-mm incision group than in the 2.8-mm incision group 1 day, 1 month, and 3 months after surgery (p = 0.035, p = 0.009, and p = 0.008, respectively). No other statistical significance was observed between the two groups (2.2 and 2.8 mm) during follow-up regarding corneal thickness, epithelial gaping and Descemet's membrane detachment. CONCLUSIONS: Corneal wounds with a smaller incision could be more vulnerable to external stimuli such as stromal hydration and are less stable than those with a larger incision.
Aged ; Anterior Eye Segment ; Cataract Extraction/*methods ; Corneal Stroma/pathology/*surgery ; Female ; Humans ; Male ; Middle Aged ; Surgical Wound Dehiscence/diagnosis/*prevention & control ; Tomography, Optical Coherence/*methods ; *Wound Healing

A 49-year-old man with an uncorrected visual acuity (UCVA) of 20 / 1000, a best spectacle-corrected visual acuity (BSCVA) of 20 / 400, keratometric readings of K1 = 59.88 x 82degrees / K2 = 45.88 x 172degrees, and an inferior steepening that was consistent with keratoconus in his left eye was treated with clear-cornea phacoemulsification and an intraocular lens (IOL) implantation after insertion of keraring intrastromal corneal ring segments for severe keratoconus and cataract. An asymmetrical pair of kerarings was implanted with the assistance of a femtosecond laser in September 2008; the one segment was 250 microm and the other was 150 microm and both were placed at 70degrees. Three months after the kerarings were implanted, clear-cornea phacoemulsification and IOL implantation were performed on the left eye. After surgery, both the UCVA and the BSCVA of the left eye improved by eight lines. Postoperative central keratometry showed a decrease of 7.35 diopters in the left eye. Both the postoperative refraction (-0.75 -0.75 x 60degrees) and the keratometric reading (K1 = 50.05 x 93degrees / K2 = 48.83 x 3degrees) remained stable one month following the procedures. Thus, the sequential order of intrastromal corneal rings implantation and cataract surgery can be considered as a treatment option in patients with severe keratoconus and cataract.
Cataract/*complications/diagnosis ; Corneal Stroma/pathology/*surgery ; Corneal Topography ; Follow-Up Studies ; Humans ; Keratoconus/complications/diagnosis/*surgery ; Lens Implantation, Intraocular/*methods ; Male ; Middle Aged ; Phacoemulsification/*methods ; Severity of Illness Index

PURPOSE: To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) when sterile gamma-irradiated acellular corneal tissues (VisionGraft) are used in combination with amniotic membrane transplantation (AMT) for intractable ocular surface diseases. METHODS: The medical records of fifteen patients who had DALK with AMT were retrospectively reviewed. Indications for surgery included ocular burn, bacterial keratitis, herpes simplex virus keratitis, corneal opacity with Stevens-Johnson syndrome, Mooren's ulcer, idiopathic myxoid degeneration of corneal stroma, and recurrent band keratopathy. DALK was performed using partial-thickness acellular corneal tissue and a temporary amniotic membrane patch was added at the end of the operation. RESULTS: All cases that underwent DALK with AMT became epithelialized within 2 postoperative weeks. Twelve patients showed favorable outcomes without graft rejection, corneal opacification, or neovascularization. The other three grafts developed corneal opacification and neovascularization, and required additional penetrating keratoplasty (PK). Unlike the results of previous PKs, there were no graft rejections and the graft clarity was well-maintained in these three cases for at least 8 months after PK. CONCLUSIONS: DALK using sterile acellular corneal tissues in combination with AMT may be a good therapeutic strategy for treating intractable ocular surface diseases because of lowered immune rejection, fibroblast activation, and facilitation of epithelialization. Furthermore, DALK can help stabilize the ocular surface, prolong graft survival, and may allow better outcomes when combined with subsequent PK.
Adult ; Aged ; Amnion/*transplantation ; Corneal Diseases/pathology/*surgery ; Corneal Stroma/radiation effects/*transplantation ; Female ; Graft Survival ; Humans ; Keratoplasty, Penetrating/*methods ; Male ; Middle Aged ; Retrospective Studies ; Visual Acuity ; Young Adult