The document provides an overview of the anatomy of the eye. It describes the main parts of the eye including the eyeball, adnexa, and internal structures. The eyeball contains three tunics - an external fibrous tunic, middle vascular tunic, and internal tunic. The internal tunic houses the light-sensitive retina. The adnexa includes muscles, eyelids, conjunctiva, lacrimal apparatus, and blood supply. In summary, the document outlines the major anatomical structures of the eye and their functions in vision.

1. ANATOMY
OF
THE
EYE

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

3. 3
THE POSITION
 In the Predatory species:In the Predatory species:
have set well forwardhave set well forward
 In Herbivores ,In Herbivores ,
Ruminant and rabbits:Ruminant and rabbits:
have eyes more laterallyhave eyes more laterally
to have wide area ofto have wide area of
visionvision

4. 4
Terminology of the eye
 CorneaCornea : the transparent: the transparent
part of the eyeball .part of the eyeball .
 Anterior poleAnterior pole: the highest: the highest
point on cornea .point on cornea .
 Posterior polePosterior pole : the: the
highest point on posteriorhighest point on posterior
surface .surface .
 Optic axisOptic axis: the straight: the straight
line passing through bothline passing through both
polespoles

5. 5
The Eyeball
 EquatoEquator :an imaginary line aboutr :an imaginary line about
the eyeball, which is thethe eyeball, which is the
equidistant from the poles.equidistant from the poles.
 MeridianMeridian: is one of many lines: is one of many lines
passing from pole to pole thatpassing from pole to pole that
intersects the equator at rightintersects the equator at right
angles.angles.
• Optic nerveOptic nerve :leaves the:leaves the
eyeball slightly ventraleyeball slightly ventral
to the posterior poleto the posterior pole

6. 6
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

7. 7
Eyeball
The three tunics are:The three tunics are:
I.I. An external fibrous tunic:An external fibrous tunic: that gives form to andthat gives form to and
protects the eyeball; it’s the only completeprotects the eyeball; it’s the only complete
tunic.tunic.
II.II. A middle vascular tunic:A middle vascular tunic: that consist largelythat consist largely
of blood vessels and smooth muscleof blood vessels and smooth muscle
 concerned with the nutrition of theconcerned with the nutrition of the
eyeball and the regulation of theeyeball and the regulation of the
shape of the lens and size of pupil.shape of the lens and size of pupil.

8. 8
Eyeball
III.III. An internal tunic:An internal tunic: that consists largelythat consists largely
of nervous tissueof nervous tissue
 concerned with vision and translation ofconcerned with vision and translation of
visual stimuli into nerve impulses forvisual stimuli into nerve impulses for
interpretation by the brain.interpretation by the brain.

9. 9
The Fibrous Tunic
 It consists of theIt consists of the sclerasclera and theand the cornea,cornea,
which meet at thewhich meet at the limbus.limbus.
1. The sclera1. The sclera is the opaque posterior part ofis the opaque posterior part of
the fibrous tunic and consists of a dense feltthe fibrous tunic and consists of a dense felt
work of colagenous and elastic fibers and iswork of colagenous and elastic fibers and is
generally white but in some species itgenerally white but in some species it
contain pigment cellscontain pigment cells

10. 10
The fibrous tunic
 The corneaThe cornea forms about one quarter of theforms about one quarter of the
fibrous tunic and bulges forward. It isfibrous tunic and bulges forward. It is
composed off dense connective tissuecomposed off dense connective tissue
arranged in lamellar form .arranged in lamellar form .
 The cornea doesn’t contain blood vessels;The cornea doesn’t contain blood vessels;
nutrients for its cells permeate from vesselsnutrients for its cells permeate from vessels
in the limbus or are carried to it its surfacein the limbus or are carried to it its surface
in the lacrimal fluid and aqueous humor .in the lacrimal fluid and aqueous humor .

11. 11
The vascular Tunic (uvea)
 Deep to the sclera, which it composed ofDeep to the sclera, which it composed of
three zones .three zones .
1) The choroids:1) The choroids: lies on the sclera from thelies on the sclera from the
optic nerve to the limbus and contains aoptic nerve to the limbus and contains a
dense network of blood vessels embeddeddense network of blood vessels embedded
in heavily pigmented connective tissuein heavily pigmented connective tissue

12. 12
The vascular Tunic (uvea)
 In the dorsal part of the fundus the choroids forms colored,In the dorsal part of the fundus the choroids forms colored,
light-reflecting area known aslight-reflecting area known as tapetum lucidumtapetum lucidum
 is avascular layer (cellular in the carnivores, fibrous inis avascular layer (cellular in the carnivores, fibrous in
ruminants and horses) between the capillaries and theruminants and horses) between the capillaries and the
vessels.vessels.
 The tapetum makes the eyes of animals shine when theyThe tapetum makes the eyes of animals shine when they
look toward the light.look toward the light.
 Our eyes and those of the pig don’t have a tapetum so theyOur eyes and those of the pig don’t have a tapetum so they
don’t reflect the light.don’t reflect the light.
 This reflecting of light is a night vision adaptation becauseThis reflecting of light is a night vision adaptation because
of stimulation of the light sensitive receptors in the retina.of stimulation of the light sensitive receptors in the retina.

13. 13
The vascular Tunic (uvea)
2) The ciliary body2) The ciliary body ::
toward the limbus the choroidstoward the limbus the choroids
thickness to form it.thickness to form it.
3) The Iris:3) The Iris: the smallest part of thethe smallest part of the
vascular tunic, which extends fromvascular tunic, which extends from
the cornea to the lens.the cornea to the lens.
 It attached to sclera and ciliaryIt attached to sclera and ciliary
body by pectinate ligament.body by pectinate ligament.
 the opening in the center is thethe opening in the center is the
pulpipulpi

14. 14
The vascular Tunic (uvea)
 The iris divided the space between theThe iris divided the space between the
lens and cornea into anterior andlens and cornea into anterior and
posterior chambers tat communicateposterior chambers tat communicate
through pupil and filled with, aqueousthrough pupil and filled with, aqueous
humor (a clear watery fluid).humor (a clear watery fluid).
 The color of the iris determines theThe color of the iris determines the
color of the eyecolor of the eye
 depends on the number of thedepends on the number of the
pigmented cells present in itspigmented cells present in its
stromastroma
 the type of the pigment in thethe type of the pigment in the
cells.cells.

15. 15
The internal tunic
 The internal tunic of the eyeball containsThe internal tunic of the eyeball contains
the light-sensitive receptor cells (known asthe light-sensitive receptor cells (known as
retina).retina).
 It’s an extension of the brain to whichIt’s an extension of the brain to which
remains connected by the optic nerve.remains connected by the optic nerve.

16. 16
The internal tunic
The layers in retina are:The layers in retina are:
 A single layer of pigmented cells.A single layer of pigmented cells.
 Aneuroepithelialm layer containing theAneuroepithelialm layer containing the
receptor cells, rods and cones and theirreceptor cells, rods and cones and their
nuclei.nuclei.
 the rods for black and whitthe rods for black and whit
 the cones for the color vision.the cones for the color vision.
 A layer of bipolar ganglion cells.A layer of bipolar ganglion cells.
 A layer of multipolar ganglion cellsA layer of multipolar ganglion cells
nonmyelinated axons lying internal to thenonmyelinated axons lying internal to the
cells and pass to the optic disc where theycells and pass to the optic disc where they
form the optic nerve.form the optic nerve.
 The optic disc is a blind area because thereThe optic disc is a blind area because there
is no receptor cellis no receptor cell..

17. 17
 The adnexa of the eye
1.1. The orbital fasciaeThe orbital fasciae ::
a.a. The periorbital:The periorbital: is attachedis attached
near the optic foramen at thenear the optic foramen at the
apex of the cone .apex of the cone .
b.b. The superficial muscularThe superficial muscular
fascia:fascia: lies within thelies within the
periorbital. It’s loose and fatty.periorbital. It’s loose and fatty.
And envelops in the levatorAnd envelops in the levator
palpebrae superioris and thepalpebrae superioris and the
lacrimal gland.lacrimal gland.
c.c. The deep muscular fascia:The deep muscular fascia: isis
more fibrous and arises from themore fibrous and arises from the
eyelids and from the limbus ofeyelids and from the limbus of
the eyeball.the eyeball.

18. 18
 The adnexa of the eye
2.2. The muscles of theThe muscles of the
eyeball:eyeball:
 The rectus muscles: dorsal,The rectus muscles: dorsal,
ventral, medial and lateralventral, medial and lateral
are inserted anterior to theare inserted anterior to the
equator by wide but veryequator by wide but very
thin tendons.thin tendons.
 The ventral and dorsalThe ventral and dorsal
oblique muscles: attach tooblique muscles: attach to
the eyeball near the equator.the eyeball near the equator.

19. 19

20. 20
 The adnexa of the eye
2. 2. The muscles of the eyeball:The muscles of the eyeball:
 The retractor bulbi arisesThe retractor bulbi arises
from the vicinity of thefrom the vicinity of the
eyeball and inserted on theeyeball and inserted on the
eyeball posterior to theeyeball posterior to the
equator.equator.
 The levator palpebraeThe levator palpebrae
superioris: striated musclesuperioris: striated muscle
within the orbit that doesn’twithin the orbit that doesn’t
attach to the eyeball butattach to the eyeball but
passes over it to enter andpasses over it to enter and
elevate the upper eyelidelevate the upper eyelid

21. 21
 The adnexa of the eye
3. 3. The eyelids and conjunctivaThe eyelids and conjunctiva : :
 The eyelids (palpebrae) are two The eyelids (palpebrae) are two
musculofibrous folds of which musculofibrous folds of which
the upper is the more extensive the upper is the more extensive
and more mobile.and more mobile.
 The free margins of the lids are The free margins of the lids are
meet at the medial and lateral meet at the medial and lateral
angles of the eye and bound an angles of the eye and bound an
opening known as the opening known as the
palpebral fissure.palpebral fissure.

22. 22
 The adnexa of the eye
3. The eyelids and conjunctiva3. The eyelids and conjunctiva : :
They are consist of three layers:They are consist of three layers:
1.The skin: is thin and delicate and is 1.The skin: is thin and delicate and is
covered with short hairs: it may also covered with short hairs: it may also
carry a few prominent tactile airs.carry a few prominent tactile airs.
2.The musculofibrous layer: is formed 2.The musculofibrous layer: is formed
by the orbicularis oculi, the orbital by the orbicularis oculi, the orbital
septum, the aponeurosis of the levator septum, the aponeurosis of the levator
muscle and the smooth tarsal muscle.muscle and the smooth tarsal muscle.
3.The mucous (palpebral conjunctiva) a 3.The mucous (palpebral conjunctiva) a
thin, transparent mucous membrane thin, transparent mucous membrane

23. 23
 The adnexa of the eye
3. The eyelids and3. The eyelids and
conjunctivaconjunctiva : :
 The third eyelid is The third eyelid is
supported by a T-shaped supported by a T-shaped
piece of cartilage.piece of cartilage.
 Bar lies in the free edge of Bar lies in the free edge of
the fold and stem points the fold and stem points
backward into the orbit backward into the orbit
medial to the eyeballmedial to the eyeball. .
 The stem of cartilage is The stem of cartilage is
surrounded by lacrimal surrounded by lacrimal
gland (the gland of the third gland (the gland of the third
eyelid).eyelid).

24. 24
 The adnexa of the eye
4.4. The lacrimal apparatus:The lacrimal apparatus:
 This consists of lacrimal glandThis consists of lacrimal gland
properproper
 The lacrimal gland is flat andThe lacrimal gland is flat and
lies between the eyeball and thelies between the eyeball and the
dorsolateral wall of orbit.dorsolateral wall of orbit.
 The glands associated with theThe glands associated with the
third eyelidsthird eyelids
 several small accessory glandsseveral small accessory glands
• duct system that conveys theduct system that conveys the
lacrimal fluid after it haslacrimal fluid after it has
washed over the eye into thewashed over the eye into the
nasal cavity for evaporation.nasal cavity for evaporation.

25. 25
 The blood supply of the eye:
 The arteries can be divided into three groups:The arteries can be divided into three groups:
1.1. THOSE SUPPLY EYEBLLTHOSE SUPPLY EYEBLL
2.2. SUPPLY OCULR MUSCLESSUPPLY OCULR MUSCLES
3.3. THOSE LAEVING THE ORBIT TO SUPPLY THOSE LAEVING THE ORBIT TO SUPPLY
ADJCENT STRCTURES. ADJCENT STRCTURES.
 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 blood supply of the eye:
 1) The branches of the external 1) The branches of the external
ophthalmic for the eyeball penetrate ophthalmic for the eyeball penetrate
the sclera to reach the vascular the sclera to reach the vascular
tunic and retina.tunic and retina.
 -Short posterior ciliary a. /-Short posterior ciliary a. / supply supply
the adjacent choroids in addition to the adjacent choroids in addition to
branches to the optic nerve.branches to the optic nerve.
 --Long posteriorLong posterior ciliary a. /ciliary a. /pass pass
close the sclera closer to the close the sclera closer to the
equator.equator.
 -The anterior ciliary a. /-The anterior ciliary a. / supply supply
the anterior potion of the choroids, the anterior potion of the choroids,
the ciliary body and the iris the ciliary body and the iris
 These arteries anastomose to form These arteries anastomose to form
the greater arterial circle of thethe greater arterial circle of the
iris.iris.

27. 27
 The blood supply of the eye:
2) The arteries that supply the ocular muscles. 2) The arteries that supply the ocular muscles.
Which the absence of the large vessels in Which the absence of the large vessels in
distal ends reduces bleeding when the distal ends reduces bleeding when the
muscles are cut during the enucleating.muscles are cut during the enucleating.

28. 28
 The blood supply of the eye:
3) The arteries that leave the orbit: 3) The arteries that leave the orbit:
 -The lacrimal a. /-The lacrimal a. / supply the lacrimal gland in supply the lacrimal gland in
route.route.
 --The supraorbital a. /The supraorbital a. / send branches to the upper send branches to the upper
eyelidseyelids
 -The malar a. /-The malar a. /supply the eyelids and also supply the eyelids and also
adjacent area of the face.adjacent area of the face.
 -The external ethamoid a. /-The external ethamoid a. / supply the ethamoid supply the ethamoid
labyrinth of the nasal cavity.labyrinth of the nasal cavity.

29. 29
 The nerve supply of the eye:
 The optic nerve II:The optic nerve II: enters the orbit through enters the orbit through
the optic foramen and passes to the light the optic foramen and passes to the light
receptor cells in the retina.receptor cells in the retina.
 It allows the movements of the eye and is It allows the movements of the eye and is
covered by meninges that it acquired during its covered by meninges that it acquired during its
development.development.

30. 30
 The nerve supply of the eye:
 The Oculomoter nerve III:The Oculomoter nerve III: control the movement of the control the movement of the
eyeball. it enters the orbit through the orbital fissure.eyeball. it enters the orbit through the orbital fissure.
 Supply: dorsal, medial, ventral Rectus muscleSupply: dorsal, medial, ventral Rectus muscle
 Ventral oblique muscleVentral oblique muscle
 Part of retractor musclePart of retractor muscle
 The abducent nerve VI:The abducent nerve VI: enters through the orbital enters through the orbital
foramen and innervates most of retractor bulbi and lateral foramen and innervates most of retractor bulbi and lateral
rectus muscles.rectus muscles.

31. 31
 The nerve supply of the eye:
 The trochlear nerve IV:The trochlear nerve IV: innervate innervate
 Dorsal oblique muscleDorsal oblique muscle
 The trigeminal nerve V:The trigeminal nerve V: send branches to the eye.send branches to the eye.
 Opthalmic divisionOpthalmic division
Give sensory branches to:Give sensory branches to:
1- long ciliary nerve of the eye, lacrimal and supraorbital 1- long ciliary nerve of the eye, lacrimal and supraorbital
nerves.nerves.
 Maxillary divisionMaxillary division
 Zygomatic branch supply ventrolateral segment of the Zygomatic branch supply ventrolateral segment of the
eyelids and conjunctivaeyelids and conjunctiva

32. 32
 The nerve supply of the eye:
 The facial nerve VII:The facial nerve VII:
 passes between the eye and the ear gives passes between the eye and the ear gives
auriculopalpebral branch auriculopalpebral branch
 innervates the orbicularis oculi innervates the orbicularis oculi

33. PRESENTED BY
A.SAI CHARAN
B.PHARMACY
TCPS
HAP
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