The Hudson-Stahli line is a line of iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 deposition laying roughly on the border between the middle and lower thirds of the cornea. It lies in the corneal epithelium

Corneal epithelium

The corneal epithelium is made up of epithelial tissue and covers the front of the cornea. It acts as a barrier to protect the cornea, resisting the free flow of fluids from the tears, and prevents bacteria from entering the epithelium and corneal stroma.The corneal epithelium consists of several...

. Usually it has about 0.5 mm in thickness and is 1–2 mm long. It is generally horizontal, with possible mild downward trend in the middle. It is present normally in people over the age of 50, but seems to dissipate to some degree by the age of 70.

The Hudson-Stahl line is not associated with any pathology calling for clinical intervention. Formation of the line may depend upon the rate of tear

Tears

Tears are secretions that clean and lubricate the eyes. Lacrimation or lachrymation is the production or shedding of tears....

secretion.

External links

• Hudson-Stähli Line - University of Columbia
• Bilateral UV photographs of corneas from four normal subjects - HS lines, a figure from a study (PMID 16186341)