This document provides an overview of the anatomy of the eyeball. It describes the three main layers - the outer fibrous layer including the sclera and cornea, the middle vascular layer containing blood vessels and the iris, and the inner retinal layer which is light sensitive. Key structures of the eye discussed include the iris, pupil, lens, ciliary body, retina, macula, fovea and optic disc. The document also covers drainage of aqueous humour, innervations of the eye, glaucoma and cataracts.

1. EYE BALL
DR SANA YASEEN
ANATOMY DEPARTMENT

2. EYE

4. LAYERS OF EYE BALL
 Outer fibrous layer:
o Tough, white , fibrous
o Sclera (posterior) cornea (ant)
 Middle vascular layer:
o Contains network of blood capillaries,
o Pigmented black
o Ant is modified to into ciliary body and iris
o Iris containing hole called pupil controled by radial and circular muscles
o Behind iris is biconcave lens attached to ciliary body via suspensory
ligament
 Inner retinal layer: is light sensitive layer
o Macula lutea: posterior part oval shaped yellowish area, distinct vision
o Contains fovea centralis/ yellow spot (image is formed , contain only cones)
o Blind spot

5. •Cornea: clear front window of the eye that transmits and
focuses light into the eye. Corrective laser surgery reshapes the
cornea, changing the focus.
•Iris: colored part of the eye that helps regulate the amount of
light that enters. circular structure, with an aperture in the centre
(the pupil). The diameter of the pupil is altered by smooth
muscle fibres within the iris, which are innervated by the
autonomic nervous system.
•Pupil: dark aperture in the iris that determines how much light
is let into the eye .

6. •Lens: Focuses light rays onto the retina. The lens
is transparent, and can be replaced if necessary.
Our lens deteriorates as we age, resulting in the
need for reading glasses. Intraocular lenses are
used to replace lenses clouded by cataracts.

8.  Ciliary body – comprised of two parts – the ciliary muscle and
ciliary processes. The ciliary muscle consists of a collection of
smooth muscles fibres. These are attached to the lens of the eye by
the ciliary processes. The ciliary body controls the shape of the lens,
and contributes to the formation of aqueous humor.
 Sclera
The white outer coat of the eye, surrounding the iris.
 Choroid
Layer containing blood vessels that lines the back of the eye and is
located between the retina (the inner light-sensitive layer) and the
sclera (the outer white eye wall).
 Retina
The nerve layer lining the back of the eye. The retina senses light
and creates electrical impulses that are sent through the optic nerve
to the brain.

10.  Macula
The area in the retina that contains special light-sensitive
cells. also known as fovea is resposible for sharp detailed
central vision (visual acuity). The deterioration of the
macula is a common condition as we get older (age related
macular degeneration or ARMD).
 Fovea
The center of the macula which provides the sharp vision.
 ora serrata
the peripheral termination of the retina. Its name derives
from the scalloped pattern of bays and dentate processes;
the retina extends further anteriorly on the medial side of the
eye. The ora serrata is approximately 2 mm wide and is the
site of transition from the complex, multilayered neural retina
to the single, nonpigmented layer of ciliary epithelium. A firm
attachment between the retina and vitreous, the vitreous
base, extends several millimeters posterior to the ora serrata.

11.  Optic disc ( blind spot): area where optic nerve attaches
to retina does not contain any photoreceptors.
 RODS : cylindrical photoreceptors found in greatest
concentration on the edges of the retina; most common
type receptor. It allows us to see in low light andd provide
peripheral vision.
 CONES: connical photoreceptors found in greatest
concentration near the center of retina; there are three
types of cones, each most sensitive to a particular
wavelength (colour) of light- blue, green, red. It allow us
visual acuity ( sharp vision) and color vision.

16. DRAINAGE OF AQOUS HUMOUR

17.  Canal of schlem: venous passages that drain the
fluid that accumulates behind the cornea, located
where the sclera and cornea meet.
 AQUEOUS HUMOR- watery fluid that provides
nutrition and helps maintain tha shape of the cornea;
found in the smaller, anterior chamber of the eye.
 VITREOUS HUMOR- thick, gel like substance that
fills the largest chamber of the eye and helps to hold
its spherical shape.

19. INNERVATIONS
 OPTIC NERVE
 Occulomotor nerve:
 Trochlear nerve:
 Abducent nerve:
 Autonomic nerve:

20. GLAUCOMA

25. CATARACT
 A cataract is a clouding of the lens in the eye which
leads to a decrease in vision.
Causes:
 Congenital esp rebulla virus
 Trauma
 Aging

26. Congenital cataract