The ocular surface is formed by three component tissues: The cornea, conjunctiva, and limbus all play an important role in keeping a good and clear corneal graft. As part of non-immunological reactions, glaucoma and ocular surface disorders can increase the possibility of corneal graft failure. For that reason, maintaining a healthy and moist ocular surface, depends on an intimate relationship between healthy ocular surface epithelia, the tear film, and the eyelid, which will all increase corneal graft survival. A moist conjunctiva composed of lymphatic tissue as our defense mechanism against infection, will keep the cornea avascular, remaining crystal clear, dehydrated, and protected. Ocular surface epithelium cannot survive without tears. To specified, each component tissue that forms the ocular surface is equally important. Several previous studies revealed that dry eye disease as a form of ocular surface disorders (OSD), can lead to graft rejection. To our knowledge, there are two conditions that cause dry eye syndrome. It can be caused by lipid tear deficiency or aqueous tear deficiency. The severity of dry eye also ranges widely with some mild inflammatory processes leading to severe chronic conditions (i.e., cicatrizing conjunctivitis) that are known to be an absolute contraindication for total or full penetrating keratoplasty. The basic immunological mechanism of dry eye, as one of the most forms of ocular surface disorders that altered corneal graft survival will be discussed specifically in this chapter.
Part of the book: Dry Eye Syndrome