Editing Corneal transplantation (section)

==Risks==
The risks are similar to other intraocular procedures, but additionally include graft rejection (lifelong), detachment or displacement of lamellar transplants and primary graft failure. Use of immunosuppressants including cyclosporine A, tacrolimus, mycophenolate mofetil, sirolimus, and leflunomide  to prevent graft rejection is increasing but there is insufficient evidence to ascertain which immunosuppressant is better.<ref>{{Cite journal|last1=Abudou|first1=Minawaer|last2=Wu|first2=Taixiang|last3=Evans|first3=Jennifer R|last4=Chen|first4=Xueyi|date=27 August 2015|title=Immunosuppressants for the prophylaxis of corneal graft rejection after penetrating keratoplasty|journal=Cochrane Database of Systematic Reviews|volume=2015 |issue=8|pages=CD007603|doi=10.1002/14651858.cd007603.pub2|pmid=26313245|pmc=9233756 |issn=1465-1858}}</ref> In a Cochrane review which included low to moderate quality evidence, adverse effects were found to be common with systemic mycophenolate mofetil, but less common with topical cyclosporine A or tacrolimus.

There is also a risk of [[infection]]. Since the cornea has no blood vessels (it takes its nutrients from the [[aqueous humor]]) it heals much more slowly than a cut on the skin. While the [[wound]] is healing, it is possible that it might become infected by various [[microorganisms]]. This risk is minimized by antibiotic [[prophylaxis]] (using antibiotic eyedrops, even when no infection exists).

There is a risk of cornea rejection, which occurs in about 10% of cases.<ref>[http://www.mayoclinic.com/health/cornea-transplant/MY00491/DSECTION=risks Cornea transplant Risks – Tests and Procedures – Mayo Clinic<!-- Bot generated title -->]</ref> Graft failure can occur at any time after the cornea has been transplanted, even years or decades later. The causes can vary, though it is usually due to new injury or illness. Treatment can be either medical or surgical, depending on the individual case. An early, technical cause of failure may be an excessively tight stitch [[cheesewiring]] through the [[sclera]].

Infectious disease transmission through corneal transplantation is exceedingly rare.<ref>{{cite journal|last=Simonds|first=RJ|title=HIV transmission by organ and tissue transplantation|journal=AIDS|year=1993|volume=7|pages=S35-38|doi=10.1097/00002030-199311002-00008|pmid=8161444|s2cid=28488664|url=https://zenodo.org/record/1234768}}</ref> All corneal grafts are screened for the presence of viruses such as HIV or hepatitis through antibody or nucleic acid testing, and there has never been a reported case of HIV transmission through corneal transplant surgery.<ref>{{cite journal|title=EBAA Medical Standards|journal=International Journal of Eye Banking|year=2017|volume=5|issue=3|url=https://eyebankingjournal.org/article/ebaa-medical-standards-2/}}</ref> Prior to the development of reliable HIV testing, many countries instituted [[Blood donation restrictions on men who have sex with men|bans on corneal donation by gay men]]. For example, on 20 May 1994, the United States banned corneal donation by any man who has had sex with another man in the preceding 5 years, even if all HIV testing is negative (a policy which continues to be enforced today).<ref>{{cite journal|pmid=32970105|year=2020|last1=Puente|first1=M. A.|last2=Patnaik|first2=J. L.|last3=Lynch|first3=A. M.|last4=Snyder|first4=B. M.|last5=Caplan|first5=C. M.|last6=Pham|first6=B.|last7=Neves Da Silva|first7=H. V.|last8=Chen|first8=C.|last9=Taravella|first9=M. J.|last10=Palestine|first10=A. G.|title=Association of Federal Regulations in the United States and Canada with Potential Corneal Donation by Men Who Have Sex with Men|journal=JAMA Ophthalmology|volume=138|issue=11|pages=1143–1149|doi=10.1001/jamaophthalmol.2020.3630|pmc=7516798}}</ref>