Plaquenil can be a wonderful drug to treat lupus and many other autoimmune diseases. I've been taking it for many years, probably 15+. Because I'm also diabetic, I've had a retina specialist specialist checking me twice a year, doing all the standard tests mentioned above. I began to have vision disturbances about 15 months ago - it appeared as double vision to me, but gradually worsened and started including difficulty with low light, blank spots in vision, blurred vision, photosensitivity and more. I told both eye doctors, my neurologist (who referred me to a neurologist at a major teaching hospital), my rheumy, and my PCP. Finally my rheumy asked if anyone had referred me to a neuro-opthamologist (they hadn't), so he did immediately. He saw me, said he was concerned about plaquenil toxicity. I naively commented that I didn't think that was possible because I've been monitored faithfully for years and have had no plaquenil changes. He said that often happens, but that a test called a "multifocal ERG" can actually test the cells of the retina. You almost always have it done at a hospital, most regular eye doctors (even retinologists) don't have the equipment. With 48 hours I had the diagnosis that I have plaquenil toxicity in both eyes and have to stop the plaquenil immediately. So I'm waiting for the impact of no plaquenil to hit. But most of all, THE DAMAGE IS IRREVERSIBLE AND WILL WORSEN BECAUSE PLAQUENIL STAYS IN YOUR SYSTEM A LONG TIME. Please, please remember this: If you are on Plaquenil 5 years or more, ask if you should have a multifocal ERG test. All my eye specialists had been monitoring and nothing showed up, but that's because it often doesn't without this test. There was a change to the guidelines in 2011, recommending the ERG and/or other tests. All the usual tests - Amsler grid, field of vision, etc. - are important, but they may not detect plaquenil toxicity and retinal damage until it's too late, and it appears even many experts are not aware of this. So regardless of the fact that this is relatively rare, it's not rare enough that they don't tell you to be monitored. Please make sure to ask about that test if you're on Plaquenil for 5 years or more.