Wife cannot get rid of pinkeye

I had several encounters with CSW over the last 2 years.  All have been protected vaginal, and on 1 occasion there was unprotected oral by me on her, not the other way around.  The last encounter was with a woman who had a bad red eye (almost too bad for pinkeye), bad enough that i asked her about it.  I can't remember how she answered but she didn't say pinkeye.  I have been symptom free during all of this.  I also have been tested for all STD's by a urine test that was sent off for testing.  The results all came back negative and i haven't had any encounters since then.  My question is this.  My wife has had recurring pinkeye for almost a year now.  She has gone to the doctor 3 or 4 times and they just give her prescription ointment or drops and tell her that it will be gone for good with the medicine.  It doesn't go away though.  It keeps flaring back up.  She doesn't wear makeup except about once a week and she has recycled her makeup several times now and nothing helps.  She is overly frustrated as you can imagine.  Could this be chlamydia?  Or some other STD?  Considering i was always protected, with no breaking of the condoms, and since i got tested and it was negative you would think so, but i just can't figure out the pinkeye not going away with the medicines she's been prescribed.