The concept of legal blindness is complex and varies depending on the country. In the UK, to be certified as severely sight impaired (blind), your sight must fall into one of the following categories, while wearing any glasses or contact lenses that you may need: visual acuity of less than 3/60 with a full visual field. However, legal blindness may fall in between the mentioned categories, i.e., visual acuity between 3/60 and 6/60 with reduced field of view (tunnel vision) . Its important to note that prescription has nothing to do with legal blindness. The benchmark is 20/200 BEST CORRECTED in the better of the two eyes.