Limbal ring explained

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] The thickness of the limbal ring varies by pupil dilation: When the pupil is larger, the limbal ring narrows.[4] Some contact lenses are colored to simulate limbal rings.[1]

Youth, health, and attractiveness

Both health and youth 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]

See also

Notes and References

  1. United States . US7246903B2 . Johnson and Johnson Vision Care Inc. . Tinted contact lenses with combined limbal ring and iris patterns . 24 July 2007 .
  2. Shyu . Betsy P. . Wyatt . Harry J. . 2009 . Appearance of the human eye: Optical contributions to the 'limbal ring' . . 86 . 9 . E1069–E1077 . 10.1097/OPX.0b013e3181b4f010 . 19648842 . 39174174 .
  3. Peshek D, Semmaknejad N, Hoffman D, Foley P . 2011 . Preliminary evidence that the limbal ring influences facial attractiveness . . 9 . 2 . 137–146 . 10.1177/147470491100900201 . free . 22947961 .
  4. Shyu . Betsy P. . Wyatt . Harry J. . September 2009 . Appearance of the human eye: Optical contributions to the "limbal ring" . . 86 . 9 . E1069–E1077 . 10.1097/OPX.0b013e3181b4f010 . 1040-5488 . en .
  5. Peshek D, Semmaknejad N, Hoffman D, Foley P . 2011 . Preliminary evidence that the limbal ring influences facial attractiveness . . 9 . 2 . 137–146 . 10.1177/147470491100900201 . free . 22947961 .
  6. Brown M, Sacco DF . 2018 . Put a (limbal) ring on it: Women perceive men's limbal rings as a health cue in short-term mating domains . . 44 . 1 . 80–91 . 10.1177/0146167217733072 . 28978250 .
  7. Li . De-Quan . Chen . Zhuo . Song . Xiu Jun . de Paiva . Cintia S. . Kim . Hyun-Seung . Pflugfelder . Stephen C. . April 2005 . Partial enrichment of a population of human limbal epithelial cells with putative stem cell properties based on collagen type IV adhesiveness . Experimental Eye Research . 80 . 4 . 581–590 . 10.1016/j.exer.2004.11.011 . 0014-4835 . 2906384 . 15781286 .
  8. James . S. Elizabeth . Rowe . Andrea . Ilari . Luca . Daya . Sheraz . Martin . Robin . July 2001 . The potential for eye bank limbal rings to generate cultured corneal epithelial allografts . Cornea . 20 . 5 . 488–494 . 0277-3740 . 10.1097/00003226-200107000-00010 . 11413404 . 21296292 . en-US .
  9. Utheim . O.A. . Pasovic . L. . Raeder . S. . Eidet . J.R. . Fostad . I.–G. . Sehic . A. . Roald . B. . de la Paz . M.F. . Lyberg . T. . Dartt . D. A. . Utheim . T.P. . 2019-03-12 . Effects of explant size on epithelial outgrowth, thickness, stratification, ultrastructure, and phenotype of cultured limbal epithelial cells . . 14 . 3 . e0212524 . 10.1371/journal.pone.0212524 . free . 1932-6203 . 6413940 . 30861002 . 2019PLoSO..1412524U . en .

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