Board Thread:Theories and Speculation/@comment-25132842-20180312025951/@comment-4624287-20180327005034

yeah but the people that went blind, madara, itachi, sasuke and izuna, all used susano'o a lot. obito and kakashi never used susano'o and didn't go blind (or hit it very well). granted, kakashi activated his late and obito had hashirama cells in him, so there are variables. the only common thread to the blindness is susano'o tho. even shisui had MS and showed no signs of blindness.

maybe the blindness is from using jutsu that are beyond the eye's physical cap. manifesting ethereal flames or physical titans from your eyes could be beyond its power cap. that would be the reason why reality changing dojutsu render the eye completely blind.

the EMS could raise that power cap to be able to have prolonged access to those dojutsu (not reality changing ones tho).