OpenType fonts may contain more than 65,000 glyphs, which allows a single font file to contain many alternate glyphs, such as old-style figures, small capitals, fractions, swashes, superiors, inferiors, titling letters, contextual and stylistic alternates, and a full range of ligatures.
Historically, some of the highest quality typefaces have included different designs for different print sizes. Several of Adobe's OpenType fonts include optical size variations such as: caption, regular, subhead and display. Called “Opticals,”these variations have been optimized for use at specific point sizes. Although the exact intended sizes vary by family, the general size ranges include: caption (6-8 point), regular (9-13 point), subhead (14-24 point) and display (25-72 point).