Amazon, the world’s largest internet retailer, will be required to make some of its web software more accessible to blind people, under the terms of a $6m legal settlement agreed between Target, the discount retailer, and the National Federation of the Blind.

The NFB took legal action two years ago against Target in California, arguing that its e-commerce website, one of the busiest in the US, was not sufficiently accessible to software programs used by blind people to read online text aloud.