Best way to denote an accessible entrance?

I’ve not been able to locate a tag or amenity for ‘entrance_accessible’.
What is the best way to indicate an entrance for mobility or visually-impaired persons?
In the case of visually-impaired – my desire is to locate a specific lat/lon point rather than a generic building entrance.
Thanks in advance for thoughts and suggestions.
Michael
CapMac GeoGO Project
http://www.capmac.org/GeoGO_Project.html

http://wiki.openstreetmap.org/wiki/Key:wheelchair
http://wiki.openstreetmap.org/wiki/Disabilities