My pet rat's eye turned blood red: health problem?

We have four rats; Lily is my oldest, she's about 2 years and 2 months old.
For the last six months she has slowly been losing all of her hair on her
hind quarter, and has been developed a slight limp. However, she still can
prance and run, just not as graciously as she used to.

A couple of weeks ago we noticed that her right eye had become cloudy white,
like she was getting a cataract. Her ability to see didn't appeat to be any
worse for wear, so I assume that her other eye is fine.

However today I noticed that her right eye has changed to red. It seems to
me that she might have blood within her eye, and I don't know what to do.
Nothing appears to be leaking out; Lily doesn't appear to be in any pain.
Her behaviour is normal, and she still lets me pick her up.

Any ideas on what this could be? My first thought was to take her to a
local vet...but what can a vet possibly do? She is far too tiny a creature
to undergo eye surgery (its difficult enough on humans, and our eyeballs
must be at least 50 times the volume of a rat's eyeball.) Maybe some other
diagnostic or treatment can be done? But then again, how long do rats live?
Surgery might shorten her life, and she is already old for a rat. I am thus
thinking that perhaps I should just allow her to continue her life as
normally as possible.


Robert