Blueblocker sunglasses will help eliminate some of the severity of the visual stimuli, and even any pair of sunglasses will do. Bringing a friend to shop, I am lucky to have someone close to me with visual problems as well, so we can even joke about the symptoms "WOW, did you see how that weird creature on the cereal box was creepy?" or how that row of perfectly placed cans just look weird, patterned, and geometrically illusioned?
Honestly, I have found the odd coping mechanism of humor for my constant visual distortions. However, these huge MEGAmarkets seem like the inside of a science fiction movie set. One drug free option: Try shopping at a local market, you can support your community and avoid the lights.
Generally, the overstimulation of lights are treated well with Blueblocker-type sunglasses. The advice I give for visual problems in general is:
Wear sunglasses as often as you need! It is drug-free! This may seem to be a silly idea, but wearing sunglasses outdoors (even if it isn't that sunny) will help lessen the impact of going from a bright environment to a dark environment when you go from outdoors to indoors. The reason is that when a person with visual perceptual problems like this go out in the sunlight, your brain tries to adapt to the large amount of visual stimuli it receives by lessening their impact. So, when you enter a darker room, the brain is still set to filter out lots of visual stimuli and it is difficult for you to see anything. Wearing sunglasses helps lessen the difference between the two environments.
Avoid taking stimulants before goigng to the store. This includes caffeine. Caffeine and other stimulants can aggravate your symptoms and even if not affecting your visual system, it will make you edgy.
If you do not have problems with obsessive compulsive behavior: Try adding your items together in your head while you walk (helps develop those cognitive behavioral neurons as well and help with mental focus) and reward yourself if you get the math right at check out by treating yourself to something extra.
Remember that you have this trigger, so try to come up with an emotional or cognitive technique that can work for you to combat this trigger from being set off. Perhaps playing a favorite song right before getting into the super market and then singing it in your head until you get past your trigger point. If you find that it does trigger again, but at least it triggers farther into the market - then you have made a success. Next time, see if you can go farther.
I think those should help!
Oh, to all of those who have e-mailed me: "I will get to them, tonight I had a special event to attend to."