pgAdmin is a GUI tool that allows “visual” access & tools for PostgreSQL database objects, data etc., and various support of maintenance activities such as backups and restores
This same type of work is also available using PostgreSQL client applications like psql (CLI) , pcopy, pg_restore.
A person unable to use pgAdmin due to a vision disabilities would be able to perform similar work using PostgreSQL client applications.
pgAdmin team has done numerous improvements for accessibility, and continues to do the same. pgAdmin also have a high contrast theme for vision disabilities.
Please feel free to report any accessibility problems and the team will fix them.