Prominent<unk>  A<unk>  is a dark<unk>  around the iris of the eye, where the sclera meets the cornea. It is a dark-colored manifestation of the corneal limbus resulting from optical properties of the region. The appearance and visibility of the<unk>  can be negatively affected by a variety of medical conditions concerning the peripheral cornea. It has been suggested that<unk>  thickness may correlate with health or youthfulness and may contribute to facial attractiveness. Some contact lenses are colored to simulate<unk> s.
Limbal ring
Stenopaeic slit
Ranula
Munk's Roll
Phrygian cap 
Clitoral hood
Kock pouch
Neural clique