It is very odd that You would flare after nine months NSD! You must be frustrated, as I was when it happened to me (from eating too much cheese).
Yes, fasting would help very much. and I have taken even other measures You might also be interested in but I am not encouraged to discuss here; You are welcome to send me an email request for both fasting and iritis information: firstname.lastname@example.org
Apples are not in season here, so I am reluctant to do them, but if a four or five day water-only fast is not possible, I would do a different monodiet of some other fruit.
It is a personal choice, but I prefer You would use the drops because of the uncertainty behind the cause--that is the basic cause, it is still the IgA-Kp, certainly, but the food trigger if any would be important to determine.
And the drops can prevent damage (if used for very brief periods), so hands down get to an ophthalmologist or someone who can provide the steroid drops. I don't know about the dilating drops--these may not be as necessary, but You should ask the expert there with You right in front of them.
I hope this is a very brief issue, but let me say once again how much I HATE IRITIS!!!