Some people are very sensitive to Plaquenil. It is a quinolone, drug after all. Similar in chemistry to the fluorquinolones which have a fluorine atom added to the ring structure.

Plaquenil:
http://en.wikipedia.org/wiki/Hydroxychloroquine

Cipro:
http://en.wikipedia.org/wiki/Ciprofloxacin

Both share the double phenolic rings with some modification
of the side chains.

These drugs are related.

People with scotomas, should be tested for homocysteine.
When homocysteine builds up in the blood from faulty methylation chemistry, it irritates the linings of the blood vessels. This leads to blood clots and blockages. Children with a rare genetic problem called hyperhomocysteinuria, die in their 20's from strokes and heart attacks.

If people have an genetic error in methylation called MTHFR polymorphism (10-30%) in US, then the homocysteine builds up in adulthood leading to vascular damage. B6, MethylB12, and methylfolate are the cofactors to reducing homocysteine, as they convert it to SAMe, which works in the body.
People with circulation problems in the retina, should be tested for elevated homocysteine levels...as that is where it shows up first. This problem if present is readily fixable without toxic drugs.

Another useful treatment is curcumin. It has shown in studies a benefit for endothelial inflammation. A quality version of this has to be used, that has had absorbtion increased. LongVida or Curcugel are examples of enhanced curcumin.

I agree it is difficult when one gets to a certain point, where potentially toxic drugs have to be used. It is a difficult decision and benefits vs risk have to be figured out.