Corneal transplantation is the most commonly performed transplantation procedure, and in most cases also the most successful type of transplantation. This is however only true for corneal diseases which are considered to be a low-risk diseases. The main characteristic of such eyes is avascularity and lack of inflammation; corneal graft success rate in such eyes is over 90%. Namely, cornea and anterior eye chamber are immune-privileged sites of our body; meaning that the foreign antigen grafted in those sites has unexpectedly high survival rate even without any anti-inflammatory treatment. However, in eyes with vascularisation and/or inflammation of the cornea, corneal graft survival rate drastically decreases to only 20-40%, even with the use of systemic anti-inflammatory treatment. Such a low graft survival rate makes the decision to perform a corneal graft a questionable one, especially in patients with systemic diseases disabling the postoperative use of aggressive systemic drugs.