Poor vision is enough a hardship for the elderly. But such vision problems, when they can’t be corrected, also appear to be tied to a shorter lifespan, according to a new study.

Previous studies have suggested a link between poor vision and death, but researchers wanted to know what might explain the association.

Dr. Michael J. Karpa, of Westmead Millennium Institute, Sydney, Australia, and colleagues studied more than 3,600 people who were 49 and older in the early 1990s. By 2007, more than a third of them - 1273 people - had died.

Those with vision problems that couldn’t be corrected were 35 percent more likely to have died during those 13 years, and those with such problems who were younger than 75 were more than twice as likely to have died.

The most likely possible tie between poor vision and death, according to the study in the Archives of Ophthalmology? Trouble walking.

The researchers speculate that not only might the elderly who don’t see well fall more, but they may also be less likely to see a doctor regularly or to have prescriptions filled. They may be more socially isolated and less able to seek urgent help when needed.

They may also be less likely to exercise regularly, which could put them at higher risk of death from various illnesses.

Finally, it’s possible that some of the reasons for poor vision could be due to poor diet, which can lead to heart disease and other killers, according to the authors.

SOURCE: Archives of Ophthalmolology, October 2009.