Tiresias was designed for subtitling by Dr. John Gill from the Royal National Institute for the Blind (RNIB), in the United Kingdom.

The Tiresias font is designed to have characters that are easy to distinguish from each other, especially important for the visually impaired. The following key factors were considered during the design process: character shapes, relative weight of character stokes, intercharacter spacing, and aspect ratios that affect the maximum size at which the type could be used.

The benefits of the Tiresias font are greatest on lower resolution displays, such as televisions, train and airline information terminals, and low resolution displays on wireless communication and handheld devices.

InfoFont is for printed instructions on public terminals where legibility is the primary consideration; these instructions are often read at a distance of 30 to 70 cm. Infofont is not designed for large quantities of text.

The Tiresias LPfont is a large print typeface specifically designed for people with low vision. Large print publications should be designed to specifically help with reading problems, and should not just be an enlarged version of the ordinary print. The Tiresias LPfont family, made up of roman, italic, and bold weights, was designed to address and solve these issues.

The RNIB developed PCfont for people with low vision to use on computer screens. It is designed for use at larger sizes only. PCfont includes delta hinting technology in the font to ensure pixel-perfect display at key sizes.

Signfont is for fixed (not internally illuminated) signage. The recommended usage is white or yellow characters on a matt dark background.

Note that the “Z” versions have slashed zeroes, and are identical in all other respects.

These faces were developed together with Dr. John Gill of the National Institute of the Blind, Dr. Janet Silver; optometrist of Moorfields Eye Hospital, Chris Sharville of Laker Sharville Design Associates, and Peter O'Donnell; type consultant.

Tiresias himself is a figure from Greek mythology, a blind prophet from Thebes.