Limbal ring
A limbal ring is a dark ring around the iris of the eye, where the sclera meets the cornea.[1] It is a dark-colored manifestation of the corneal limbus resulting from optical properties of the region.[2] The appearance and visibility of the limbal ring can be negatively affected by a variety of medical conditions concerning the peripheral cornea.[3] It has been suggested that limbal ring thickness may correlate with health or youthfulness and may contribute to facial attractiveness.[3][4] Some contact lenses are colored to simulate limbal rings.[1]
Both health and age are positively correlated with a prominent limbal ring.[5] For instance, a darker limbal ring tends to be found more attractive than the absence of a limbal ring, suggesting that both sexes "use the limbal ring as a probabilistic indicator of reproductive fitness".[5] Furthermore, limbal rings appear to be most noticeable "for individuals relatively free from chronic health issues"[6].
The limbal ring is thought to contain corneal epithelium stem cells.[7] Diseases involving a limbal stem cell deficiency are associated with blindness, as those with such deficiencies are "unable to maintain a stable corneal surface.".[8] Transplantation of limbal stem cells is a promising therapy for limbal stem cell deficiency.[9]
Commentaires
Enregistrer un commentaire