What do you mean by OECD and non-OECD,(mentioned in CAT-IIM)? Which countries fall under these categories? What is the proper definition(in terms of specs power) of "People of low-vision" as said in cat bulletin?

OECD stands for the Organization for Economic Co-operation and Development. IT has 30 member countries all of which are working together to follow similar guidelines in co-operation with another relating to development, sanititsation etc. These countries include Germany, Australia, Belgium, Finland