Human Eyeball Structure in 15 min.


Watch our Free Video on the brief structure of Human Eyeball


Layers of Human Eyeball:

The eyeball has three basic layers: 1. Outermost layer. 2. Middle layer. 3. Innermost layer.

Outermost Layer (Protective layer):

This layer has two parts: 1. Cornea: Anterior 1/6 area of the outermost layer is transparently called Cornea. 2. Sclera: Remaining posterior 5/6 of the outermost layer is made of white collagens called Sclera.

Middle Layer (Vascular layer, Uveal Tract):

-Inner to the sclera, there is a main vascular layer. It extends from the posterior surface, i.e. posterior area of

the eyeball to the anterior surface of the eyeball. It becomes thick as it approaches anteriorly, this thickened part is called the Ciliary Body and the remaining vascular layer behind this thickened part is called Choroid. -Anterior most part of this layer is like a diaphragm structure with a central aperture, i.e. Pupil, and this diaphragm-like structure is called Iris. – Uveal Tract: This whole vascular layer having Choroid, Ciliary Body, and the iris is actually called the Uveal The tract is a vascular pigmented middle layer of the eyeball.

Innermost Layer (Retina):

The innermost layer is called Retina, it has a lot of rods and cones. It terminates at Ora Serrata.


Behind the pupil, there is a lens. The lens is attached by ligaments to the ciliary body and these ligaments are called

Zonules or Suspensory ligaments.

Vitreous Humor

Behind the lens, there is a vitreous body containing vitreous humor.

Blood Supply to Eyeball:

  Blood is mainly supplied to the eyeball by the ophthalmic artery. This artery has the following branches: 1. Central retinal artery: This artery enters through the optic nerve and supplies the retina. 2. Short posterior ciliary artery: This artery enters into the eyeball outside the optic nerve and supplies choroid, as it does not reach up to the anterior part and does not supply blood to the ciliary body and iris so it is called Short posterior ciliary artery. 3. Long posterior ciliary artery: This artery supplies blood to the ciliary body and iris. The length of this artery is more than that of the short posterior ciliary artery. 4. Anterior ciliary artery: This is the muscular branch of the ophthalmic artery and it enters into the eyeball from the anterior part, making anastomosis with long posterior ciliary artery. It supplies blood to the ciliary body and iris.

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