iris

what is the function of the iris

Controls how much light enters the eye by varying pupil size by shifting the size and therefore either increasing or reducing the gap

what is the average size of the pupillary zone

1.5mm

what is the size of the pupil

1-9 mm

what is a wolfflin nodule

bundles of collagen resulting from atrophy in the stromal layer

what are contraction furrows

Rings that extend around outer border of iris • Resulting from contraction and dilation of pupil

what is conjunctival melanosis

Spotting that is observed outside of the iris, on the sclera, often benign

what are the layers of the iris

1. Anterior border layer

2. Stroma • Contains sphincter muscle

3. Anterior epithelium • Contains dilator muscle

4. Posterior epitheliu

what are properties of the anterior border layer

• A very thin layer

• Extension of the stroma

• Two cell types exist here - Fibroblasts , Top •, Pigmented melanocytes , Underneath fibrobalsts

• Anterior border layer absent at Fuch’s crypts

• Ends at the iris root

what are melanocytes

cell types found in the hair skin and eyes that create pigment

what melanocytes produce yellow and red pigment

pheomelanin

what melanocytes produce brown and black pigment

eumelanin

what is the term for two different iris colors

hetrochromia