Supposedly it is a person's eyes that we first notice when we fall in love. I'm sure that's what the Prince of Wales was looking at when he first became smitten with the busty Mrs. Fitzherbert. Either way, he presented his shy lover a token of his affection in the form of an eye miniature. Eye portraits became a common lovers' token in the late eighteenth century and into the Regency period. After all, eyes are not as conspicuous as a full miniature. This makes them difficult to identify today. If you find one of these rare miniatures in a museum they seldom know whose eye is depicted. Many letters from the time talk of how supposed lovers had "exchanged eyes."
Eye portraits were created the same way miniatures were and usually by miniature artists such a Richard Cosway (who painted the eye for the prince to give to Mrs. Fitzherbert). The eyes would be placed on jewelery such as brooches or rings to display that the wearer's heart belonged to someone. Some settings even have a wife's eye surrounded by her childrens'. Other eyes were not put on constant display and only shown to select parties, but that usually meant that they already had someone else's eye, if you get my drift, wink wink.