Something wrong with eyes

Back in November my cat Pudden started having trouble with here eyes. They would start to tear up as if she poked them and then go back to normal in a few minutes. Then one night she rubbed her left eye which resulted a scratch on her cornea. I took her in and she was given a dye test. The vet never mentioned an ulcer so I assumed it was just an abrasion. She was given drops for 2 weeks and then was fine.

Now she started again with the sudden tearing. Yesterday she rubbed her right eye which again resulted in a scratch on the cornea. I am currently giving the drops I still have from the first time.

Her eyes are not red, there is no puss or indication of disease. She just starts trearing a few minutes a day and then one day will rub one of her eyes and get a scratch.

Could this be the herpes virus? She had an incident with a spot on her eye 10 years ago, but it was treated and never came back. Pudden also has trouble with URIs.

Another possibility I was thinking was dry eye. She is 18 so maybe she is no longer making enough tears? I am $4000 in the hole with all of Pudden's many ailments (diabetes, asthma, uti, fic, eye problems) I just can't afford another vet visit right now. So I am just going to give the drops I still have, but I am thinking of trying lysine to see if it stops this from happening again. Any thoughts on what this could be?

There is no way we can diagnose via the internet, but in my way of thinking, the L-Lysine couldn't hurt.  Plus, if she has a history of URI, together with this history of tearing,it does sound a bit like Feline Herpes. 

Are you keeping her nails trimmed way down to prevent her scratching her cornea?  That might help, or the use of soft paws (something like this: http://www.thecatsite.com/products/soft-claws-soft-paws-for-cats 

It doesn't sound like dry eye,at least not according to this article:  http://www.petwave.com/Cats/Health/Dry-Eye.aspx

From what I have read I agree she doesn't have any of the symptoms of dry eye except the corneal abrasions. From my understanding dry eye is also very rare in cats.

I purchased some lysine yesterday and am waiting for it to arrive. I really hope it works and keeps these eye problems at bay! Pudden is declawed in her front paws, but she does rub her eyes and this is what causes the tearing.