@pedie I know that it has been some time since your post, but I want nonetheless share some possibly useful information that I found in scientific literature. I hope that in the meantime you condition has at least stabilized.
I also have been diagnosed with npAIR and I'm experiencing continuing loss of in my visual field despite being on immunosuppressors since one month now. I'm not a physician, but as a molecular biologist and researcher I think I can grasp enough of the medical literature to make some reasonable hypothesis. After reading a lot of case reports and retrospective case studies my idea is that the cases that are classified under non-paraneoplastic AIR are actually still a collection of medical conditions with similar symptoms but possibly different etiologies. In my case for example no major anti-retinal antibodies have been detected! This would also explain why some patients respond to some therapies, while other do not or, conversely, why in some patients the progression of the symptoms stops spontaneously. One possible cause for npAIR has been hypothesized as the local reactivation of viruses belonging to the herpes family and in some cases a therapy with antivirals has been attempted with success. I was able to convince my physicians of that and since three days I'm now, parallel to immunosuppression, also on valacyclovir.
Given the low risk, but possible high gain of such therapy I'm convinced such an attempt should be made as first line treatment as soon as the diagnosis of npAIR is suspected (also because immunosuppressive therapy may actually be counterproductive if the origin is viral).
I hope this helps... I'll keep you posted about how this therapy works on my side.
Fabio

PS: I wanted to post here some links to supporting literature but as newly registered member I'm not allow to include URLs. Please search for these two papers:
1. Vinit B. Mahajan and Edwin M. Stone (2010) Patients with an Acute Zonal Occult Outer Retinopathy-like Illness Rapidly Improve with Valacyclovir Treatment. Am J Ophthalmol. 2010 Oct; 150(4): 511–518.
2. Saira Khanna, Aline Martins, [...], and Mihai Mititelu. (2019). Non-paraneoplastic autoimmune retinopathy: multimodal testing characteristics of 13 cases. Non-paraneoplastic autoimmune retinopathy: multimodal testing characteristics of 13 cases. J Ophthalmic Inflamm Infect. 2019; 9: 6. (See patient #5, Fig. 4)