Your Card Explained
Your card may carry identifying symbols to indicate extra privileges granted to the holder. They are explained here:

Free concessionary travel for people with a disability and over 60 year olds
Free concessionary travel for people with a disability plus a companion.
Free concessionary travel for people who are blind or visually impaired. Also entitles cardholders to the National Blind Scheme Concessions.
Free concessionary travel for registered blind or partially sighted individuals plus a companion.
Indicates that the cardholder may be entitled to other concessions in their local area.
Indicates that the cardholder and their companion may be entitled to other concessions in their local area.
Card issued for use in Strathclyde Partnership for Transport (SPT) areas. Councils within SPT region provide additional local concessionary discounts for people over 60 years old or with disabilities.
Integrated Transport Smartcard Organisation is a Government-backed, non-profit organisation which defines and develops the UK-wide technical specification for smart ticketing in transport.