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KEYWORDS Cornea / Corneal transplant / Donor age / Keratoplasty /Limbal transplant
Provenance and Peer review: Unsolicited submission; Peer reviewed
Corneal disease is one of the major causes of blindness worldwide. Removal of the damaged cornea and transplant of donated tissue is often the only option available to patients to improve and restore vision. This paper discusses corneal transplant with consideration given to penetrating keratoplasty (PK), a traditional full thickness corneal transplant and three other surgical techniques that offer an alternative to the traditional PK surgery: deep anterior lamellar keratoplasty (DALK), deep lamellar endothelial keratoplasty (DLEK) and limbal stem cell transplant.
Introduction
The World Health Organisation (WHO) estimate that there are approximately 10 million people worldwide who are visually impaired due to corneal disease (WHO 2004). Each year around 80,000 patients worldwide receive corneal transplant surgery (Thomas et al 2006). Figures for corneal transplant vary from country to country with the USA undertaking the majority of cases, approximately 40,000 in total. UK Transplant (2008) reported a figure of 2,403 transplants performed in the UK in 2006-2007. Data can be difficult to access in some countries where no transplant register exists such as the Republic of Ireland. Guerin et al (2008) have highlighted the difficulties imposed by this when trying to effectively quality assure corneal transplant survival rates and urged the health authority in the Republic of Ireland to take action to improve this situation.
Cornea
The cornea is a transparent convex structure and its main responsibility is the refraction of light entering the eye. The cornea's structure consists of five layers: an outer layer of epithelium and four inner layers - Bowman's layer, stroma, Descemet's membrane and endothelium. Damage caused to any of these corneal layers can result in a loss of transparency and shape ultimately resulting in impaired vision. Once damage has occurred to the cornea a corneal transplant is often the only viable option for patients to successfully recover their vision (Oliver & Cassidy 2005).
The cornea has proved to be one of the most successfully transplanted tissues, although lack of donation, poor graft survival rate, and insufficient universal access can leave many people blinded for life. Recent scientific developments and advances in technology have brought about exciting changes to surgical...