Per IRS Pub 501, anything short of total blindness requires a certified statement from your eye doctor.
Not totally blind.
If you aren't totally blind, you
must get a certified statement from an eye doctor (ophthalmologist or
optometrist)
that:
-
You can't see better than 20/200 in the better eye with glasses or contact lenses, or
-
Your field of vision is 20 degrees or less.
If your eye condition isn't likely to
improve beyond these limits, the statement should include this fact.
Keep the
statement in your records.
If your vision can be corrected
beyond these limits only by contact lenses that you can wear only
briefly because
of pain, infection, or ulcers, you can take
the higher standard deduction for blindness if you otherwise qualify.
https://www.irs.gov/publications/p501/ar02.html#en_US_2016_publink1000220721
