The average diameter of the human iris is 12 mm.
The iris is the colored part of the eye located behind the cornea and in front of the lens. Its primary function is to control the amount of light that enters the eye through the pupil.
While the average diameter is 12mm, the iris's thickness is not uniform. It is thickest at the collarette, which is a circular ridge located approximately 1.5 mm from the pupillary margin (the edge of the pupil). The thickness thins out towards both the pupil and the periphery of the iris.
Key Iris Features:
- Diameter: Approximately 12 mm on average.
- Thickness: Varies, thickest at the collarette.
- Function: Controls pupil size and regulates light entry.
Therefore, when considering the "size" of the iris, it's essential to specify whether you are referring to its diameter or thickness, as they are distinct measurements. The 12 mm refers to the diameter.
