NO MATTER HOW much lifespans are being stretched, the very last chapter is often grim. From the age of 80, in the rich world one person in five will be afflicted with some form of dementia, one in four will suffer from vision loss and four in five will develop hearing problems. Of those who make it to 90, the majority will have at least one health problem that counts as a disability; many will have multiple ones. Unfairly, for poorer and less well-educated people this decline often starts sooner.
Source: New technology for old age