To report the clinical outcomes of lamellar keratoplasty using sterile, gamma-irradiated corneal tissues (VisionGraft) for partial-thickness corneal defects.
Interventional case series.
The medical records of 10 patients with partial-thickness corneal defects who were operated at The Wilmer Eye Institute between April 2009 and December 2009 were retrospectively reviewed. Indications for surgery included corneal melt with microperforation (n = 6), keratoprosthesis-associated corneal melt (n = 2), and noninflammatory limbal lesions (n = 2). The grafts were fashioned from full- or partial-thickness tissues using disposable trephines, based on the depth, shape, and size of the defect in the recipient bed, and were secured with multiple interrupted 10/0 nylon sutures. Rate of epithelialization and clarity of the grafts at the last visit were assessed retrospectively.
All but 1 graft became epithelialized between postoperative 1st and 13th days. Corneal inflammation progressed in the 1 patient with Boston type 1 keratoprosthesis-associated corneal melt, probably attributable to the progression of underlying Sjögren syndrome, despite initiation of systemic immunomodulatory treatment, and required replacement of the device. The donor tissues remained clear in all the other cases over a period of 7 to 15 months. No immune rejection, infection, significant opacification, or neovascularization of the donor tissues were noted during a follow-up period.
VisionGraft may be considered in lieu of fresh donor corneas for lamellar corneal patch grafts because of its availability, easy handling, and lack of immunogenicity.
Localized corneal defects that require emergency management, such as microperforations secondary to underlying autoimmune diseases, remain a challenge to the ophthalmic surgeon. The treatment options for these cases include management of the area of corneal thinning with tissue adhesives, conjunctival flaps, amniotic membrane grafting, patching with scleral lamellae, patching with fresh corneal tissue, or employing glycerin-preserved corneal tissues.
The VisionGraft Sterile Cornea is a sterile gamma-irradiated cornea with a shelf life of 1 year at room temperature. It has been recently made available by Tissue Banks International (TBI; Baltimore, Maryland, USA) for ophthalmic surgeons’ use. Currently, the tissue is provided precut in various shapes and sizes with full- or partial-thickness stroma for use in lamellar transplant procedures.
We report herein the indications and clinical outcomes of lamellar keratoplasty using VisionGraft Sterile Cornea in a small group of patients with partial-thickness corneal defects.
A total of 10 patients (10 eyes) were operated between April 6, 2009 and December 12, 2009 at The Wilmer Eye Institute. Indications for surgery included microcorneal perforation with inflammation (n = 6), keratoprosthesis-associated corneal button melt (n = 2), and noninflammatory limbal lesions (n = 2). The majority of the patients had an underlying condition resulting in clinically significant dry eye syndrome.
All surgeries were performed by the same surgeon (E.K.A.) in a similar fashion. The VisionGraft Sterile Cornea grafts were fashioned from whole- or partial-thickness lenticules using disposable corneal trephines, based on the shape and size of the defect in the recipient bed, and varied between 3 and 6 mm in diameter. In corneal beds requiring small eccentric patches, same-size grafts were used. A 0.25-mm-oversize graft was used to patch larger corneal defects, measuring 5 to 6 mm. In patients with microcorneal perforations, a limbal stab incision was first created with a disposable metal knife, through which the miotic and air were sequentially injected into the anterior chamber. In Patients 2, 3, and 10, the iris tissue plugging the area of perforation had to be released using a Barraquer sweep to re-form the anterior chamber. A partial-thickness corneal trephination was then created using disposable metal trephines to prepare the host bed, while the perforated area was plugged with air in the anterior chamber. The recipient bed was prepared by excising a partial-thickness corneal tissue using a disposable crescent blade. The excised tissue was submitted for histopathologic examination to rule out a possible infectious etiology.
In patients with keratoprosthesis-associated corneal button melts, the extent of melting and exposed keratoprosthesis were carefully measured. The graft was fashioned in the shape of a donut using 7.75- to 8.5-mm hand-held disposable metal trephines for outer diameter and 3-mm for inner diameter. The graft material was sliced into equal halves with a pair of surgical scissors. The recipient bed was then marked using the same size with the larger hand-held metal trephine. Partial-thickness trephination was performed carefully to mark the bed, without penetrating the Descemet membrane. A crescent blade was then used to excise a partial-thickness corneal tissue to fit the lenticules in the host bed. The 2 crescentic donors were then sewn in place, around the stem of the device, using 10/0 nylon interrupted sutures. This surgical technique has been described previously.
In patients with noninflammatory limbal mass lesions, a limited conjunctival periotomy was created to expose the area. The lesion was then scored with a disposable metal trephine to create a partial-thickness incision. The lesion was then excised using deep lamellar dissection, leaving the Descemet membrane exposed but intact, with a crescent knife, and was removed in its entirety. Previously prepared oversized, full-thickness grafts were then secured in the recipient bed using interrupted 10/0 nylon sutures. Conjunctiva was approximated into position using interrupted 8-0 vicryl sutures.
The depth of the dissection in the recipient bed in each case was based on the depth of the pathology. The Descemet membrane was not violated in any of the cases. The thickness of the corneal lenticule was adjusted to match the depth of dissection.
At the end of each operation, subconjunctival injection of cefazolin and dexamethasone was performed. A combination of antibiotic and steroid ointment (gentamicin sulfate 0.3%, prednisolone acetate 0.6%, PredG Ointment; Allergan Inc, Irvine, California, USA) was used to dress the eye before the eyepatch and a shield were placed. Patients with underlying immunologic disorders were placed on systemic treatments as necessary. Topical treatment with the ointment was continued 4 times daily for the first week and tapered over an additional 3 weeks before being discontinued. Patients were followed up with respect to the rate of epithelialization, clarity of the grafts, and any complications occurring in the postoperative period.
Patient demographics, clinical characteristics, and postoperative outcomes are summarized in the Table . There were 8 female and 2 male patients. Eight of the surgeries were performed after hours on an emergency basis. The underlying diseases in cases with a microcorneal perforation included neurotrophic ulcer in the setting of herpetic keratitis, severe melting from culture-proven bacterial keratitis, Stevens-Johnson syndrome with exposure keratitis, and severe dry eye with an underlying sarcoidosis and Sjögren syndrome. One of the patients with a keratoprosthesis-associated melt also had an underlying Sjögren syndrome. Etiologies in the 2 patients with noninflammatory lesions included limbal dermoid and Rosai-Dorfman disease ( Figure 1 , top and bottom).
|Patient No.||Age/Sex||Initial Presentation||Previous History||Histopathology||Comorbidities||Follow-up (Months)||Outcome|
|1||66/F||Corneal ulcer with microperforation||Bacterial infectious keratitis||Corneal necrosis with no active infection||Diabetes mellitus, rheumatoid arthritis with severe sicca||13||Graft in place, epithelialized, and clear; interface with mild neovascularization|
|2||7/M||Corneal ulcer with microperforation||Nonhealing epithelial defect||Corneal necrosis with no active infection||Stevens-Johnson syndrome with severe sicca||11||Graft in place, epithelialized, and clear|
|3||67/F||Corneal ulcer with microperforation||Nonhealing epithelial defect||Corneal necrosis with no active infection||Sjögren syndrome with severe sicca||10||Graft in place, epithelialized, and clear; interface with mild neovascularization|
|4||65/M||Corneal ulcer with microperforation||Bacterial infectious keratitis||Corneal necrosis with no active infection||Diabetes mellitus||7||Graft in place, epithelialized, and clear; interface with mild neovascularization|
|5||48/F||Corneal ulcer with microperforation||Nonhealing epithelial defect||Corneal necrosis with no active infection||Atopy, presumed herpetic keratitis||7||Graft in place, epithelialized, and clear|
|6||56/F||Keratoprosthesis-associated corneal melt||Nonhealing epithelial defect||Corneal necrosis with no active infection||Chandler’s syndrome||15||Graft in place, epithelialized, and clear; keratoprosthesis intact|
|7||80/F||Keratoprosthesis-associated corneal melt||Nonhealing epithelial defect||Corneal necrosis with no active infection||Sjögren syndrome with severe sicca||13||Nonhealing epithelial defect and further melt, keratoprosthesis explantated|
|8||13/F||Limbal mass lesion||None||Limbal dermoid||None||12||Graft in place, epithelialized, and clear|
|9||14/F||Limbal mass lesion||None||Rosai-Dorfman disease||None||15||Graft in place, epithelialized, and clear|
|10||67/F||Corneal ulcer with microperforation||Nonhealing epithelial defect||Corneal necrosis with no active infection||Sarcoidosis with severe sicca||7||Graft in place, epithelialized, and clear; interface with mild neovascularization|