Eyeball

1. Dr.Khaled Ali
3rdyear medical student
Anatomy Of The Eyeball

2. Coats of the Eyeball
• The eyeball is formed of :
coat (Cornea + Sclera)
coat (Iris, ciliary body, and choroid)
• coat (Retina)

3. Fibrous Coat
- Cornea
- Sclera

4. Cornea
• It is a thin membrane which forms the anterior 1/6 of
the eyeball.
•Blood supply: It is (it receives nutrition by diffusion
from the sclera and conjunctiva)
•Nerve supply: Long ciliary nerves (from the ciliary ganglion)

5. Sclera
• It is a dense whitish fibrous tissue forming the posterior
5/6 of the eyeball.

6. Corneoscleral Junction(Limbus)
• It circumscribes the periphery of the anterior chamber.
• It contains a canal called the (sinus venosus
sclerae).
• Its inner wall contains (perforations) which drain
the aqueous humor (the clear fluid in the anterior chamber) into the
canal of Schlemm.

7. Vascular Coat
- Choroid
- Ciliary body
- Iris

8. Choroid
• It is a thin, , and (brown) area which forms the
posterior 5/6 of the vascular coat.
• It lines the pigmented cell layer of the retina.

9. Ciliary Body
• It lies at the corneo-scleral junction (as a flat ring at the inner surface
of sclera) where it blends with the choroid at ora serrata.

10. Parts
a. Ciliary processes: It connects the ciliary body to the
b. Ciliary muscle

11. Ciliary muscle
•Structure: Unstriated muscle formed of fibers.
•Action; Its relaxes the suspensory ligament of the lens
allowing it to bulge ( ).
•Function:It helps to focus the lens for near vision ( ).
•Nerve supply: n. (through fibers from Edinger-Westphal
nucleus).

12. Iris
• It is the of the eyeball between the anterior and posterior
chambers.
• Its peripheral part is attached to the ciliary body.
• Its central part contains a central hole called the .

13. Sphincter and Dilator pupillae muscles
a. Sphincter pupillae (narrows the pupil)
-It is a band of smooth muscle lying at the margin of the pupil.
-It is supplied by fibers from the ciliary ganglion
through the short ciliary nerves (derived from the Edinger-Westphal
nucleus)

14. b. Dilator pupillae (dilates the pupil)
• -It is a smooth muscle fibers
• -It supplied by fibers from ciliary ganglion

15. Blood Supply
• -It is supplied by branches from the
(from the ophthalmic artery)

16. Nervous Coat
- Retina

17. Retina
- It extends between the posteriorly to the
anteriorly.

18. It contains the following features:
1. Macula lutea
• -It is a oval area at the center of the posterior wall
containing high pigment.

19. 2. Fovea Centralis
• -It is a central depression in the macula lutea.
• -It contains (specialized receptors) and responsible for
where the

20. 3. Optic disc
• -It is a circular pale area 1.5 mm in diameter, 3 mm medial to the
macula lutea.
• -It is the site where the of the ganglion cells the retina
where it overlies the lamina cribrosa of the sclera.
• -There are (rods or cones) in it, hence it is
, so it is called the

21. Blood supply
(smallest and most important branch from the
ophthalmic artery).