I hope your iritis cleared up soon - it can be extremely painful to say the least!
I had chronic iritis for about ten years, well before I ever had any signs of diabetes, so for me the two were completely unrelated. However, I was using dexamethasone eye drops for all that time, and corticosteroids
can affect glucose levels, so as a T2 I have since wondered if these were a partial cause of my later diabetes. but I found a reference implying that in eye drop form corticosteroids
won't affect glucose levels - which I thought a bit strange.
On doing a quick search for you though I haven't found this information again. so maybe using such eye drops could cause a rise in glucose levels - so these rather than iritis itself might be diabetes related.
My ongoing issue was with bright lights, but due to migraines I was already using photo sensitive glasses for my eyes to be comfortable.