Eye burning,visual snow

I apologize in advance for my poor english(I am a Slovak)
I have problems with brain fog for more than a year and it realy destroing my life.I ve always had a skin problems
(dry skin,dandruff in hair)and suffer for several allergies,but year ago a started to have a problem with brain fog,
appearance of flashing lights before the eyes and burning(dry)eyes.I,ve visited several doctors,they did big amout of tests but they didnt find anything.
I had some improvment when i tried to use pro liver or detoxical pills,i also ALWAYS get better after drinking beer.(just beer,other alkoholic drinks made it worst).
Any ideas what is wrong?I also have to add my new finding that eye burning get much worse after using valerian drops,but gets much better when i eating something cold like icream or if i just put a piece of ice in my mouth.