A possible explanation for these vision disturbances?

First of all, I've seen two eye doctors and they see nothing wrong with my eyes, aside from needing glasses. My family doctor suggested I see a nuerologist, which I've yet to do but will schedule the appointment. I'm 24 yrs. old. I started using meth when I turned 19 and quit when I was 20. I had none of the following symptoms prior to use. When I was using it, I noticed what looked like all these little cells or flickers running along the walls and streaming around in my eyes. I still have them and they never went away. I think this is called persistant visual snow, or I guess it could be HPPD and I have it all the time, still. My vision started to get worse as well and I now wear glasses. I also saw all these little white lights starting at the outside of my eyes and working their way in from all sides after using it one time. This still happens once or twice a month, since. When I look at the sky or other well lit surfaces, or in the dark, the visual snow gets much worse, it looks like I can see all the cells in my eyes. Could it be that's what I'm seeing? I know there is something like that that people can get. I also have quite a few black floaters in each of my eyes. A recent development is, since June, when I turn my eyes quickly, or hear a loud noise that startles me while relaxing, or switch from a light room to a dark room or vise versa, I see circles of purple light everywhere that last a couple of seconds. Sometimes they're big, sometimes they're small. Sometimes they're small and white as well. I get these atleast 5 times a day, sometimes more. The meth did something to change my vision. Perhaps it brought out persistant migraine aura without infraction (since I seldom get headaches.) Or maybe it did some permanent damage to nerve endings? Extreme anxiety and panic attacks came with the drug use if that is in relation to a possible diagnosis. What do you think?

[Sandra M Brown, MD]

"permanent visual snow" is a symptom I hear occasionally from patients, some of whom admit to drug use and some of whom I strongly suspect.  Your symptoms are probably due to permanent hyperexcitability of the occipital cortex, which is the part of the brain that processes vision.  You are not seeing the cells in your eyes.

Anti-seizure medications might improve your symptoms, but this seems to be rather hit or miss from patient to patient.  It's worth a try.  I have no specific medication recommendations.  Discuss this with your neurologist.