Lamellar keratoplasty involves replacement of your damaged or diseased anterior corneal stroma (middle layer of your cornea) and Bowman's membrane (second layer of your cornea) with donor material. Most of the bottom three layers of your cornea can be preserved. The donor corneal disc becomes repopulated with host cells, and the recipient epithelium usually covers the anterior corneal surface. This procedure is technically more difficult than penetrating keratoplasty. Lamellar keratoplasty has the advantage of being primarily outside the eye, making it a procedure that preserves your endothelium. The risk of rejection becomes less of an issue. The risks of wound leaks or flat anterior chambers associated with an intraocular procedure may be eliminated. Microsurgical techniques have vastly improved the technique of lamellar keratoplasty, but they have also substantially improved the results with penetrating keratoplasty. The use of conjunctival flaps and therapeutic soft contact lenses has reduced the indications for lamellar keratoplasty.