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] The thickness of the limbal ring varies by pupil dilation: When the pupil is larger, the limbal ring narrows.[5] Some contact lenses are colored to simulate limbal rings.[1]
Youth, health, and attractiveness
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Both health and youth are positively correlated with a prominent limbal ring.[6] 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".[6] Furthermore, limbal rings appear to be most noticeable "for individuals relatively free from chronic health issues".[4]
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]
See also
[edit | edit source]References
[edit | edit source]- ^ a b United States US7246903B2, "Tinted contact lenses with combined limbal ring and iris patterns", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Johnson and Johnson Vision Care Inc.[dead link]
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External links
[edit | edit source]- Error creating thumbnail: File missing Media related to Lua error in Module:Commons_link at line 62: attempt to index field 'wikibase' (a nil value). at Wikimedia Commons
