Help, my dog went blind in 2 weeks

[MJ's Zoo]

My oldest dog Loki, 12 years old this month, got an eye infection in one of her eyes. My husband took her to the vet and they noticed she had low pressure and low tear duct production in one eye and yes the infection was in the other. We got two different meds for her eyes. The vet did mention she had cataract in the eyes. Now 1 week later my husband took her back to the vet and the vet was surprised that she had gotten worse. She is now blind, completely. I'm wondering if the meds the vet gave us for Loki made it worse? The vet wants to run a bunch of test on Loki that will cost around $600 and I am broke. I am recovering from my own health problems and the bills are piling up. The vet also recommended that we take Loki to an optometrist and that will be approx $500. I honestly can't afford to pay that but I don't want my dog to suffer. I am thinking of bringing Loki to another vet for another opinion.
Any ideas? I'm really pushing my stress level here. I can't take much more. My health is struggling, I just lost my cat to a health related injury 3 weeks ago and we're still morning. My daughter grew up with Loki. We're all coming to our end. I don't know what to do. Any suggestions would be truly appreciated.

[SummerRiot]

Do you know which drugs your vet prescribed for you?

[bubbatd]

I would get a second opinion and try to pinpoint the actual cause . Poor girl .

[Renee750il]

What kind of dog is Loki?

[MJ's Zoo]

Here is a picture of Loki. She is a mut. I know her mother was a white sheppard but none of the pups looked alike. She look similar to a large border collie with a shorter snout.
http://img165.imageshack.us/img165/9295/lokipuppy2yt5.th.jpg (http://img165.imageshack.us/my.php?image=lokipuppy2yt5.jpg)

I did some searching online and I think she may have corneal ulcers. In which case I think the medications are wrong.

for her right eye, no infection, has cataract, low pressure and low tear production; Optimunne Ophthalmic

for her left eye, has infection, cataract,; Trithalmic/Cortisone Ophthalmic

The vet said there were no scratches. I have set an appointment for a second opinion on all of this for Tuesday but now I'm afraid of waiting till then. If she does have corneal ulcers and the meds she's on is worsening it, I want her to get the correct meds right away. What should I do?

[bubbatd]

I don't think one day will make a big difference ....let us know what you find out Tuesday .