Eye

explanation about eye

1. 1
Anatomy of The Eye

2. 2
INTRODUCTION
The Eye is the The Eye is the
organ of vision.organ of vision.
Composed of :Composed of :
1.1.Eyeball.Eyeball.
2.2.The adnexa. The adnexa.

3. External Anatomy of the Eye

4. Lids and Lashes
Main function is the protection of the eye.Main function is the protection of the eye.
They also help to distribute tears which They also help to distribute tears which
wash and lubricate the eyes.wash and lubricate the eyes.

5. Lacrimal Apparatus of the Eye

7. 7
Eyeball
The three tunics are:The three tunics are:
I- I- An external fibrous tunicAn external fibrous tunic
II- A middle vascular tunicII- A middle vascular tunic
III- III- An internal tunicAn internal tunic

8. Anatomy of the Eyeball
Fibrous Tunic:Fibrous Tunic:
CorneaCornea
ScleraSclera
Vascular TunicVascular Tunic
Choroid coat Choroid coat
Ciliary Body (Ciliary muscle, Ciliary process)Ciliary Body (Ciliary muscle, Ciliary process)
IrisIris
Nervous TunicNervous Tunic
RetinaRetina

9. 9
Eyeball
The three tunics are:The three tunics are:
I. I. An external fibrous tunic: An external fibrous tunic: that gives form to and that gives form to and
protects the eyeball; it’s the only complete protects the eyeball; it’s the only complete
tunic.tunic.
II.II.A middle vascular tunic:A middle vascular tunic: that consist largely that consist largely
of blood vessels and smooth muscle of blood vessels and smooth muscle
concerned with the nutrition of the concerned with the nutrition of the
eyeball and the regulation of the eyeball and the regulation of the
shape of the lens and size of pupil.shape of the lens and size of pupil.

10. 10
Eyeball

III. III. An internal tunic:An internal tunic: that consists largely that consists largely
of nervous tissue of nervous tissue

concerned with vision and translation of concerned with vision and translation of
visual stimuli into nerve impulses for visual stimuli into nerve impulses for
interpretation by the brain.interpretation by the brain.

12. 12
The Fibrous Tunic
It consists of tIt consists of t
he he sclera sclera and and
the the cornea, cornea,
which meet at the which meet at the limbus.limbus.

13. Sclera
1.1.The sclera The sclera is the opaque posterior part of is the opaque posterior part of
the fibrous tunic. the fibrous tunic.
2.2. consists of a dense felt work of consists of a dense felt work of
colagenous and elastic fibers.colagenous and elastic fibers.
3.3.It is generally white.It is generally white.
13

14. 14
Cornea
The corneaThe cornea forms about one quarter of the forms about one quarter of the
fibrous tunic and bulges forward.fibrous tunic and bulges forward.
 It is composed off dense connective tissue It is composed off dense connective tissue
arranged .arranged .
The cornea doesn’t contain blood vessels;The cornea doesn’t contain blood vessels;
nutrients for its cells permeate from vessels nutrients for its cells permeate from vessels
in the limbus or are carried to it its surface in the limbus or are carried to it its surface
in the lacrimal fluid and aqueous humor .in the lacrimal fluid and aqueous humor .

15. 15
The vascular Tunic (uvea)
Deep to the sclera, which it composed of Deep to the sclera, which it composed of
three zones .three zones .
1)1)The choroidsThe choroids
2)2) The ciliary bodyThe ciliary body
3)3) The IrisThe Iris

16. 1) The choroids:

lies on the sclera from the optic nerve to the lies on the sclera from the optic nerve to the
limbus .limbus .
contains a dense network of blood vessels contains a dense network of blood vessels
embedded in heavily pigmented connective embedded in heavily pigmented connective
tissue tissue
16

17. 17
2.The ciliary body
toward the limbus the choroids toward the limbus the choroids
thickness to form it. thickness to form it.

18. 3) The Iris
 TThe smallest part of the vascular tunic, he smallest part of the vascular tunic,
which extends from the cornea to the lens. which extends from the cornea to the lens.

It attached to sclera and ciliary body by It attached to sclera and ciliary body by
pectinate ligament. pectinate ligament.

the opening in the center is the the opening in the center is the pulpi pulpi
18

19. 19
The vascular Tunic (uvea)
The iris divided the space between the The iris divided the space between the
lens and cornea into anterior and lens and cornea into anterior and
posterior chambers that communicate posterior chambers that communicate
through pupil and filled with, aqueous through pupil and filled with, aqueous
humor (a clear watery fluid).humor (a clear watery fluid).
The color of the iris determines the The color of the iris determines the
color of the eye color of the eye

depends on the number of the depends on the number of the
pigmented cells present in its pigmented cells present in its
stroma . stroma .

20. 20
The internal tunic
The internal tunic of the eyeball contains The internal tunic of the eyeball contains
the light-sensitive receptor cells (known as the light-sensitive receptor cells (known as
retina). retina).

It’s an extension of the brain to which It’s an extension of the brain to which
remains connected by the optic nerve.remains connected by the optic nerve.

21. Histology of the retina of the
eye

22. 22
The internal tunic
The layers in retina are:The layers in retina are:

A A single layer of pigmented cells.single layer of pigmented cells.
A neuroepitheliam layer containing the receptor A neuroepitheliam layer containing the receptor
cells, rods and cones and their nuclei.cells, rods and cones and their nuclei.

the rods for black and white the rods for black and white

the cones for the color vision.the cones for the color vision.

23. Cont…
A layer of bipolar ganglion cells.A layer of bipolar ganglion cells.
A layer of multipolar ganglion cells and A layer of multipolar ganglion cells and
they form optic nerve they form optic nerve
The optic disc is a blind area because there The optic disc is a blind area because there
is no receptor cell.is no receptor cell.
23

24. Chambers of the Eye
1. Anterior chamber – from cornea to iris
2. Posterior chamber – from iris to lens –
These two are responsible for the
production and drainage of the aqueous
which is produced continuously throughout
your life.
Aqueous is produced in the posterior
chamber by the ciliary body travel through
the iris to drain out the anterior chamber
(through the Canal of Schlemn)
3. Vitreous – gel like –gives the eye its shape 3. Vitreous – gel like –gives the eye its shape
not produced – damage or loss can cause not produced – damage or loss can cause
retinas to fall or tear retinas to fall or tear

25. 25
 The blood supply of the eye:
The external ophthalmic artery carries the The external ophthalmic artery carries the
principle supply of the blood to the eye, which is principle supply of the blood to the eye, which is
a branch of the maxillary artery.a branch of the maxillary artery.

26. 26
 The nerve supply of the eye:
The optic nerve IIThe optic nerve II
The Oculomoter nerve III: The Oculomoter nerve III: control the control the
movement of the eyeball.movement of the eyeball.
The abducent nerve VI:The abducent nerve VI:

27. Intrinsic Eye Muscles and
their response to light

28. The Visual Pathway

29. 29

30. Visual Pathway
1.1.ConesCones
2.2.Bipolar neuronsBipolar neurons
3.3.Ganglion cell’s axon forms the optic nerveGanglion cell’s axon forms the optic nerve
4.4.Optic nerve to the Optic ChiasmOptic nerve to the Optic Chiasm
5.5.Optic tractOptic tract
6.6.Lateral geniculate nuclei of the thalamusLateral geniculate nuclei of the thalamus
7.7.Optic RadiationsOptic Radiations
8.8.Primary visual areas of the occipital lobesPrimary visual areas of the occipital lobes

31. Light Refractory
Pathway:
1.Bulbar Conjunctiva
2.Cornea
3.Aqueous Humor
4.Lens
5.Vitreous Humor
6.Ganglion Cell Layer
7.Inner Synaptic Layer
8.Bipolar Layer
9.Outer Synaptic Layer
10. Photoreceptor Layer

32. Abnormalities of
The Eye:
1.Myopic -
nearsighted
2.Hypermetropic -
Farsighted
3.Presbyopia -
age-related failure of
lens to accommodate
4.Astigmatism -
Distorted vision due to
irregular-shaped lens or
cornea
5.Color Blindness -
genetic defect that
causes dysfunction of
cones

33. Accommodation of the Lens
for near vision
Ciliary muscles contractCiliary muscles contract
Ciliary body pulls forward and inwardCiliary body pulls forward and inward
Lens becomes thicker (rounder) due to its Lens becomes thicker (rounder) due to its
elasticityelasticity
Pupils constrictsPupils constricts

34. Accommodation of the Lens
for far vision
Ciliary muscles relaxesCiliary muscles relaxes
Ciliary body returns to its resting state, Ciliary body returns to its resting state,
backward and outwardbackward and outward
Pupils dilatePupils dilate

35. Anatomy of Rods and Cones

36. The Muscles of the Eye
(Extraocular muscles)

37. Superior and Inferior rectus
Superior rectusSuperior rectus

Attached to the eye at 12 oAttached to the eye at 12 o’’clockclock

Moves the eye up.Moves the eye up.
Inferior rectusInferior rectus

Attached to the eye at 6 oAttached to the eye at 6 o’’clockclock

Moves the eye down.Moves the eye down.

38. Lateral Rectus
Lateral RectusLateral Rectus

Also called the external rectusAlso called the external rectus

Attaches on the temporal side of the eyeAttaches on the temporal side of the eye

Moves the eye toward the outside of the Moves the eye toward the outside of the
head (toward the temple)head (toward the temple)

39. Medial Rectus
Medial RectusMedial Rectus

Also called the internal rectusAlso called the internal rectus

Attached on the nasal side of the eyeAttached on the nasal side of the eye

Moves the eye toward the middle of the Moves the eye toward the middle of the
head (toward the nose)head (toward the nose)

41. Superior Oblique
Attached on the temporal side of the eye.Attached on the temporal side of the eye.
Passes under the Superior Rectus.Passes under the Superior Rectus.
Moves the eye in a diagonal pattern -- down Moves the eye in a diagonal pattern -- down
and in.and in.

42. Inferior Oblique
Attached on the nasal side of the eye.Attached on the nasal side of the eye.
Passes over the Inferior Rectus.Passes over the Inferior Rectus.
Moves the eye in a diagonal pattern -- up Moves the eye in a diagonal pattern -- up
and ou+t.and ou+t.

43. Accessory structures of the Eye
from a sagittal view