For the past couple of days my dog's eye had been turning red. It seems to come and go randomly and when it does happen the whole surface of the eye turns blood-red. Now this morning his eye is pink around the edges, near the lids and looks slightly swollen. He's also squinting quite a lot, so it looks as if it may be painful, and there is a bit of clear discharge. We haven't really tried anything to solve it yet because we wouldn't know where to start and we would have been to the vets earlier but it's just so expensive. If it carries on then we are going to take him to the vets tomorrow, but it would be helpful if anyone knew of any solutions we can try at home first.
Also, some more useful bits of information are that we looked after a young cat not long before it happened, so it may have been something to do with the cat, and he's 17 years old now, so it may be to do with him losing his eyesight.

With only one eye affected, there is a good chance that the eye has been injured, Unfortunately only the vet can examine it and tell you for sure.
If he is squinting then yes, it is likely painful to him.
Some injuries are so small that you will never detect them.
With his age being 17, I wouldn't take chances with his eyesight, best to get it checked out.
I will strongly advise not to put anything in the eye that you may have around, some eye medications contain steroids and depending on the problem can cause more damage.
Not saying that you would, but you would be surprised at the people who self-medicate their pets and do more harm.
Good luck, and I think the vet is your best option.

Thanks a lot for the advice :)
Having though about what you've said, it's probably likely that it is a scratch or something and I think we'll get him checked out tomorrow.
It seems to be coming and going and we were hoping that it would clear up by itself, especially as it's so expensive to go the vet and we're pretty low on money at the moment, but if it's an injury rather than some sort of infection or irritation then I guess it's in more urgent need of being checked out and I'd rather we spent the money than just leave it and risk it getting worse. It seems to have cleared up a little since this morning, but if it's bad again tomorrow we'll definitely have to get it checked out, I'm sure we can find the money from somewhere.
Thanks again for your help :)

With only one eye affected, there is a good chance that the eye has been injured, Unfortunately only the vet can examine it and tell you for sure.
If he is squinting then yes, it is likely painful to him.
Some injuries are so small that you will never detect them.
With his age being 17, I wouldn't take chances with his eyesight, best to get it checked out.
I will strongly advise not to put anything in the eye that you may have around, some eye medications contain steroids and depending on the problem can cause more damage.
Not saying that you would, but you would be surprised at the people who self-medicate their pets and do more harm.
Good luck, and I think the vet is your best option.

Thanks a lot for the advice :)
Having though about what you've said, it's probably likely that it is a scratch or something and I think we'll get him checked out tomorrow.
It seems to be coming and going and we were hoping that it would clear up by itself, especially as it's so expensive to go the vet and we're pretty low on money at the moment, but if it's an injury rather than some sort of infection or irritation then I guess it's in more urgent need of being checked out and I'd rather we spent the money than just leave it and risk it getting worse. It seems to have cleared up a little since this morning, but if it's bad again tomorrow we'll definitely have to get it checked out, I'm sure we can find the money from somewhere.
Thanks again for your help :)