Whenever I did meth and started pissing dark red pee my eyes would become so bad at focusing I needed strong reading glasses to read my monitor.
I heard eyeballs are full of liquid and it made me wonder - are my eyes being canalised for water due to the meth induced dehydration?
P.S. I mention meth because there’s a big difference in severity between normal dehydration - which is bad - and meth-induced which is 10xTERRIBLE but less easily spotted.
Eyes need lubrication to function properly so dehydration will impact them. I know when I’m lacking sleep and it’s hot at work I have trouble with focusing on things when I get home. I assume due to not producing enough tears which increase the amount of friction in your eyes and increasing the effort requires to move them around.