A portable reading device for the blind consisting of a miniature housing (2) attached to a sleeve to be fitted over the tip of the user's index finger like a thimble. The housing (2) includes an optical sensor array (5) and an electromagnetic unit for displaying one printed character at a time in Braille on a tactile surface as soon as the user's finger passes over the character. The electromagnetic unit contains six electromagnets (7) for reproducing Braille characters, and two further electromagnets for indicating incorrect tracking to the user. The latter two electromagnets are activated when the blind user's finger moves too far up or down as it runs along a line of text.