Transplant corneas are very readily available in the USA but are in short supply in the UK. Why is that? I asked my opthalmologist. Without a second's hesitation, he replied, "Gunshot wounds". Apparently it's true, and the tissue is usually very high quality because these are mostly younger people who could aim a firearm (although not quite well enough, it seems). He says that the current ban on importing donor corneas from abroad is likely to be relaxed so we can start getting some of the beneficial by-products of their stupid gun laws.