Over the last 6 months I have noticed a gradual loss of peripheral vision and in my ability to distinguish between shades of colors. I have been experiencing sudden and sometimes violent nausea. My pupils are often drastically differing in size and iv experienced a feeling of aching pressure behind my right eye, also at random times my vision will blur or the room will appear to have darkened or gotten brighter, the most recent thing is at least once daily now my peripheral vision will appear to change color, as if someone had turned on come colored ambient lighting behind me, i could also describe it as everything going purple... or blue, like looking trough stained glass for a moment. any thoughts?