The iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil. source
The iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil.
Eye color is defined by that of the iris. source
Eye color is defined by that of the iris.
In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm that serves as the aperture stop. source
In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm that serves as the aperture stop.
The iris consists of two layers: the front pigmented fibrovascular known as a stroma and, beneath the stroma, pigmented epithelial cells. source
The iris consists of two layers: the front pigmented fibrovascular known as a stroma and, beneath the stroma, pigmented epithelial cells.
The back surface is covered by a heavily pigmented epithelial layer that is two cells thick (the iris pigment epithelium). source
The back surface is covered by a heavily pigmented epithelial layer that is two cells thick (the iris pigment epithelium).
The high pigment content blocks light from passing through the iris to the retina, restricting it to the pupil. source
The high pigment content blocks light from passing through the iris to the retina, restricting it to the pupil.
The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body. source
The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body.
The iris and ciliary body together are known as the anterior uvea. source
The iris and ciliary body together are known as the anterior uvea.
The iris along with the anterior ciliary body provide a secondary pathway for aqueous humour to drain from the eye. source
The iris along with the anterior ciliary body provide a secondary pathway for aqueous humour to drain from the eye.
The pupillary zone is the inner region whose edge forms the boundary of the pupil. source
The pupillary zone is the inner region whose edge forms the boundary of the pupil.
The ciliary zone is the rest of the iris that extends to its origin at the ciliary body. source
The ciliary zone is the rest of the iris that extends to its origin at the ciliary body.
The collarette is the thickest region of the iris, separating the pupillary portion from the ciliary portion. source
The collarette is the thickest region of the iris, separating the pupillary portion from the ciliary portion.
The muscle cells of the iris are smooth muscle in mammals and amphibians, but are striated muscle in reptiles (including birds). source
The muscle cells of the iris are smooth muscle in mammals and amphibians, but are striated muscle in reptiles (including birds).
Crypts on the base of the iris are additional openings that can be observed close to the outermost part of the ciliary portion of the iris. source
Crypts on the base of the iris are additional openings that can be observed close to the outermost part of the ciliary portion of the iris.
Amber colored eyes are extremely rare in humans. source
Amber colored eyes are extremely rare in humans.
In contrast, heterochromia and variegated iris patterns are common in veterinary practice source
In contrast, heterochromia and variegated iris patterns are common in veterinary practice
When photographed with a flash, the iris constricts but not fast enough to avoid the red-eye effect. source
When photographed with a flash, the iris constricts but not fast enough to avoid the red-eye effect.
