I am an Enrolled Agent. I have a blind client that uses the blind check box. Standard deduction increases for blind tax payers.
How to Qualify As Blind By the IRS
You must keep in your tax records a certified letter from an eye doctor (or optometrist) stating that you have non correctable 20/200 vision in your best eye or that your field of vision is restricted to 20 degrees or less.
I have two stories about blind taxpayers. My first experience was getting a call from a "blind" taxpayer that he was going to be late for appointment because he could not find a parking spot. I discovered that blind is not totally blind.
The second was a client I inherited from a deceased tax preparer. This taxpayer lived in another state and we did her tax return for a number of years and did not know she was blind until we got details of a wrongful discharge lawsuit that mentioned both age and blindness. We never met her and we had no reason to think she was blind. This made me rethink my procedures but it is very rare that someone is blind and does not itemize.