Cornea Transplantation in Japan and Overseas


The cornea is the transparent tissue at the very front of the eye. There are various diseases that affect the cornea, such as keratoconus, bullous keratopathy, bacterial or viral infection, and corneal leukoplakia. The procedure known as a cornea transplant replaces all or part of a clouded cornea, due to disease or damage, with transparent donor tissue.

Eye donation is possible regardless of nearsightedness, farsightedness, astigmatism, presbyopia, syphilis, or age provided the cornea is transparent. However, donation may not be possible in the case of a donor with a potentially infectious disease – such as COVID-19. *1 There are 19,000 people in Japan with visual impairment due to corneal diseases, and about 2,200 patients nationwide are awaiting corneal transplants. *2

Data from the Gain’s report, Global Survey on Corneal Transplantation and Eye Banking, shows that there are approximately 12.7 million people in 134 countries waiting for a transplant, while only 185,000 corneal transplants are performed each year in 116 countries. *3

More than half of the patients needing corneal transplants suffer from bullous keratopathy, which is caused by edema of the cornea resulting from the dysfunction of corneal endothelial cells. There are two major factors that contribute to the development of bullous keratopathy: hereditary disease and surgical complications. Hereditary disease is represented by Fuchs’ corneal endothelial degeneration, a type of corneal dystrophy that develops in patients 50-60 years old. In terms of complications, bullous keratopathy can occur due to severe trauma to the endothelial cells during surgery for cataracts, glaucoma, or other eye conditions.

The factors causing bullous keratopathy differ slightly by country. In Europe and the USA, the disease is predominantly hereditary, while in Japan and other Asian countries, it is often the result of complications from cataract or other intraocular surgery. Regenerative treatment of the corneal endothelium, which is not dependent on eye banks, can help eliminate the large corneal transplant supply-demand mismatch and reduce the number of corneal blindness cases worldwide.