I'm not sure about erythromycin but here is a similar answer from something i read in the archives.
My cat buttons has a light greenish liquidy substance coming from her left eye, her eye also looks filmy with the same substance. This just happened 2 days ago and it's not getting better even when I wipe it off. She has never had this before. I am going to assume that this is an eye infection. What do you think?
I have these eye drops that I used when I had an eye infection... The drops are called Polycidin and they are an antibiotic for the eyes and ears. Can I use these same drops for buttons? what dose would I try? If not is there something else I could buy for this problem?
Thank-you so much for your help,
Your question is a commonly asked one and really should only be answered by a Veterinarian that knows your cat and the safety of the drug for your cat. There are a number of eye medications that are used by humans that may be safe and effective for pets, but often the concentration and the frequency of the dosage of the medication may be different.
The diagnosis of the eye infection is probably correct but the underlying cause may be bacterial, viral, allergic or traumatic with possible underlying eye problems that require a trained professional to diagnose. My advice is that while you are most likely safe to use the drops 3 x day for 5 - 7 days in the affected eye, it would be a lot safer to have it examined. You could always take your bottle of eye drops to the Veterinarian and ask him/her if the drops would be suitable. Hope this helps.
Martin Slome DVM
Centre Street Animal Hospital
Thornhill, Ontario, L4J 7Y3
Tel: (905) 771-9855