You need to have a culture taken and have it analyzed/raised in a
lab. If your ophthalmologist won't do it, find someone who will,
perhaps an internist. That should give a definitive cause. Until you
get it diagnosed you're chasing unknown territory. Since I've practiced
urine therapy for many years almost all of my eye problems have disappeared and
even my glaucoma pressure has subsided. I've also used a clean eye wash
cup and rinsed my eyes with my own fresh urine. There's a bit of a sting
at first, but then a refreshing cleanse. "Murine" is urine/urea
with an M added. Don't knock it. Fresh urine is an antiseptic.
It has cured my athlete's foot of many years standing and other skin problems as
well.