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Penetrating Keratoplasty refers to the replacement of the host cornea with a donor cornea. It is used with success in patients with decreased visual acuity secondary to corneal opacity, in the treatment of corneal thinning or perforation, for the removal of non responding infectious foci and for the relief of pain.
Pseudophakic corneal edema
Aphakic corneal edema
Keratoconus and ectasias
Corneal degenerations
Corneal dystrophies including Fuchs endothelial dystrophy
Noninfectious ulcerative keratitis
Microbial keratits including Fungal and Bacterial keratitis
Viral keratitis
Post infectious keratitis
Congenital opacities
Chemical injuries
Mechanical trauma
Refractive indications
Regraft related to allograft rejection
Regraft unrelated to allograft rejection
The initial step in Penetrating Keratoplasty should be the preparation of the donor tissue. The use a corneal button 0.25-0.50mm larger than the diameter of the host corneal openning is recommneded as it can help reduce excessive postoperative corneal flattening, reduce the risk of secondary glaucoma and enhance wound closure.
The host cornea is trephined, the anterior chamber is filled with viscoelastic and the the donor tissue is placed endothellial side down on the recipient's eye. The cornea is then sutured in place with either interrupted or continuous sutures. Interrupted sutures are preferred in vascularized, inflammed or thinned corneas as well as in pediatric cases.
Penetrating keratoplasty may be combined with cataract surgery, secondary intraocular lens implantation,glaucoma surgery and retinal surgery.
Poor graft centration
Irregular trephination
Damage to the lens
Damage to the donor tissue
Choroidal hemorrhage and effusion
Incarceration of iris tissue in the wound
Vitreous in the anterior chamber
Wound leak
Glaucoma
Endopthalmitis
Primary Endothelial failure
Persistent epithelial defect
Microbial Keratitis
Late failure
Recurrence of primary disease
A Symptoms
Decreased vision, pain, redness and photophobia after a corneal transplant
B Signs
Keratic precipitates or a white line on the corneal endothelium
Stromal edema or infiltrates
Subepithelial or epithelial edema
Conjunctival injection
Anterior chamber cells or flare
Neovascularization
C Differential Diagnosis
Increased intraocular pressure
Uveitis
Suture abscess
Corneal infection
Recurrent disease in the graft (Herpetic or corneal dystrophy)
D Treatment
Start a topical steroid, such as prednisolone acetate 1% q 1hr immediately. Use a cycloplegic agent. Systemic steroids (prednisone 40-80 mg daily) should be considered in cases that do not respond to topical steroids and in recurrent rejection episodes.