Stroma of iris

Stroma of iris is a part of the eye's iris that consists of loose connective tissue. It is located between the anterior epithelium and the posterior epithelium of the iris. The stroma of the iris is a crucial component of the eye's anatomy, playing a significant role in eye color and the regulation of light entering the eye.

Structure

The stroma of the iris is made up of a meshwork of fibroblasts and collagen fibers. These fibers are arranged in a random pattern, which contributes to the unique pattern and color of each individual's iris. The stroma also contains melanocytes, cells that produce the pigment melanin. The amount and distribution of melanin within the stroma contribute to the color of the iris.

Function

The primary function of the stroma of the iris is to help regulate the amount of light that enters the eye. It does this by controlling the size of the pupil. When the stroma contracts, the pupil becomes smaller, allowing less light to enter the eye. When the stroma relaxes, the pupil becomes larger, allowing more light to enter the eye.

The stroma also plays a role in giving the iris its color. The color of the iris is determined by the amount and type of melanin in the stroma, as well as the way the stroma scatters light. For example, a large amount of melanin in the stroma results in a brown iris, while a small amount of melanin results in a blue iris.

Clinical significance

Changes in the stroma of the iris can indicate certain health conditions. For example, iris nevus syndrome is characterized by the presence of nevi (small, benign growths) in the stroma. In some cases, these nevi can become malignant, leading to iris melanoma.

Iris coloboma is a condition in which a portion of the stroma is missing, often due to a congenital defect. This can result in a keyhole-shaped pupil and vision problems.

Fuchs' heterochromic iridocyclitis is a rare condition that can cause changes in the stroma, leading to a change in iris color.

See also

• Iris (anatomy)
• Eye color
• Human eye