choroidean

The choroidean is a vascular layer of the eye, situated between the sclera and the retina. It is part of the uveal tract, which also includes the iris and ciliary body. The primary function of the choroidean is to supply oxygen and nutrients to the outer layers of the retina, particularly the photoreceptor cells essential for vision.

Anatomically, the choroidean is composed of a dense network of blood vessels, connective tissue, and pigmented cells. Its high vascular density facilitates efficient nutrient exchange and waste removal from the retina. The pigmentation within the choroidean, primarily due to melanocytes, also serves to absorb excess light, reducing refraction and scatter that could impair visual acuity.

The choroidean's structure is divided into several layers, including the choriocapillaris—a capillary network that closely abuts the retina—and the outer and inner choroidal stroma, which contain larger blood vessels and connective tissue. The choroidean is also involved in thermoregulation and immune responses within the eye.

Clinically, the choroidean can be affected by various conditions, such as choroidal neovascularization, which involves abnormal blood vessel growth often linked to age-related macular degeneration. Other disorders include choroiditis, an inflammation of the choroidean, and tumors like choroidal melanoma.

Understanding the anatomy and physiology of the choroidean is essential in diagnosing and treating ocular diseases that impact vision and eye health. Its vital role in nourishing retinal cells underscores its importance in maintaining visual function.