olemus
ISO/IEC 19794-6:
iirise välispiir silma kõvakestaga liitumisel
=
outer boundary of the iris where it is joined to the sclera

piltlikult
https://duckduckgo.com/?q=limbus&t=h_&iax=images&ia=images

ülevaateid
https://en.wikipedia.org/wiki/Corneal_limbus

https://www.spiedigitallibrary.org/journalArticle/Download?fullDOI=10.1117/1.JEI.28.3.033022