Human eye is the biological structure which enable the sense of light. the Eyes are the windows to the wonders of the world.

1. MEDICAL SURGICAL NURSING- II
UNIT – II
NURSING MANAGEMENT OF PATIENTS
WITH DISORDERS OF EYE
TOPIC : REVIEW OF ANATOMY AND
PHYSIOLOGY OF EYE
Mrs. Soumya. M
1
PRESENTED BY
Mrs. SOUMYA SUBRAMANI, M.Sc.(N)
LECTURER, MSN DEPARTMENT
CON- SRIPMS, COIMBATORE.

2. Mrs. Soumya. M 2

3. Mrs. Soumya. M 3

4. Mrs. Soumya. M 4

5. Eyes are the paired organs that
detect light and convert it into
electro-chemical impulses in
neurons.
EYE :
The organ of VISION
Mrs. Soumya. M 5

6. Types of eye:
Simple eye
is presence in
all chordates
Compound eye
is presence in
case of arthopods
Mrs. Soumya. M 6

7. Parts of EYE
mainly
•divided into
Mrs. Soumya. M 7
parts

8. 1.Eyeball
• Three layers:
– Fibrous outer layer
• Sclera
• Cornea
– Vascular middle layer
• Choroid,
• Ciliary body and
• Iris
– The inner nervous layer
• Retina
• Pupil
• Structures inside the eyeball are the lens,
aqueous fluid and vitreous body.
Parts of EYE
Mrs. Soumya. M 8

9. Mrs. Soumya. M 9

10. 2.Accessory structures
•Conjunctiva
•Eyelid
•Eyelashes
•Lacrimal gland
•Extraocular muscles
Parts of EYE
Mrs. Soumya. M 10

11. Sclera
“White part of the eye”
Maintaining the shape and
form of the eye ball.
Contains BVs and insertion site
for extrinsic eye muscles.
Cornea
Thin, transparent epithelium
 Allow the free entry of light.
 Act as refractive media.
Fibrous outer layer
Mrs. Soumya. M 11

12. CORNEA
•Transparent avascular tissue with 5 distinct
layers.
•Function is to allow light rays to enter the
eye.
•Surrounded by a vascular layer known as the
limbus which nourishes the cornea.
•Should be smooth and clear.
Mrs. Soumya. M 12

13. Layers of the Cornea
• 1. Epithelium (5-6 layers of cells)
• 2. Bowman's layer
• 3. Stroma (about 90% of the thickness)
• 4. Descemet's layer (clear membrane)
• 5. Endothelium (1 cell layer)
Mrs. Soumya. M 13

14. Choroid
– Pigmented to absorb excess
light
– Supplies the retina with
nutrients and oxygen via
blood supply
Iris
“Colored part” of the eye
which contains pigment cells,
loose connective tissue and pupillary
muscle.
Adjusts the pupil
Regulates amount of light
Vascular middle layer
Mrs. Soumya. M 14

15. Vascular middle layer
Mrs. Soumya. M 15
Ciliary Body
Ring of smooth muscle around lens
Regulates the shape of the lens
for accommodation
Suspensatory Ligaments
– Attach the ciliary body to the lens

16. The Uveal Tract
• Composed of the choriod,
ciliary bodies and the iris.
• Middle vascular layer of the
eye.
• Divides the sclera and the
retina and the anterior and
posterior sections of the eye.
Mrs. Soumya. M 16

17. The inner nervous layer
Mrs. Soumya. M 17
Retina
is a light-sensitive layer of tissue,
lining the inner surface of the
eye.
Functions
It helps in
Photopic vision
Scoptic vision
Mesopic vision
Steroscopic vision
Acuity of vision
Color vision
Perception of movement

18. The inner nervous layer
Mrs. Soumya. M 18
Cells of retina-
I.Photoreceptor cells
II.Bipolar cells
III.Horizontal cells
IV.Amacrine cells
V. Ganglion cells
• The photo receptor
cells are 2 types -
(1)The cone cells
(2)The rod cells

19. RETINA
•Thin semitransparent multi-layered sheet of
neural tissue that lines the inner layer of the
posterior section of the globe of the eye.
Mrs. Soumya. M 19

20. Layers of the Retina
(from the outside to the inner layer)
1. Bruch’s membrane
2. Retinal pigment epithelium
3. Photoreceptor cells layer (Rods and Cones)
4. External limiting membrane
5. Outer nuclear layer
6. Inner plexiform layer
7. Ganglion cell layer
8. Nerve fiber layer
9. Internal limiting membrane
Mrs. Soumya. M 20

21. Layers of the Retina
Mrs. Soumya. M 21

22. The inner nervous layer
Mrs. Soumya. M 22
 The macula lutea/ Yellow spot
 Fovea centralis
 The blind spot/ Optic disc
 Retinal blood vessels.
 pigment epithelium cells
 Photoreceptor cells
Maculalutea
Vein
Opticdisc
Artery
Special Areas of the Retina
is an oval-shaped highly pigmented yellow
spot near the center of the retina
Fovea centralis (fovea)is a depression,
located in the center of the macula region of the
retina.
The macula

23. Macula
• That area of the retina that is responsible for central
detailed vision.
• Most concentrated area of visual sensitivity is the fovea.
• No blood vessel pass through the macula.
• Nourishment comes from the Retinal Pigment Epithelium
(RPE)
Mrs. Soumya. M 23

24. The Optic Nerve and Disk
 Consists of over 1 million axons
from the nerve fiber layer of the
retina.
 80% consists of visual fibers
synapse on axons that terminate
in the occipital lobe of the brain.
 Part of the Central Nervous
System
 Will not regenerate if severed.
Mrs. Soumya. M 24

25. Photoreceptor Cells
• Transfer light and images to nerves
that convert images to electrical
impulses that are sent to the
occipital lobe of the brain and
translated into images that we see.
• Two types: Rods and Cones
Mrs. Soumya. M 25

26. Photoreceptor Cells: Cones
• Concentrated in the macula and fovea
• Responsible for central, fine, detailed vision
• Responsible for ability to see color
• Require good light to work effectively
• Bundled with a one to one correspondence to nerve
endings that transmit light and images to the brain.
Mrs. Soumya. M 26

27. Photoreceptor Cells: Rods
• Require little light to work effectively and at night gives a
primarily grayish image
• Generally do not give clear vision
• Relatively Sensitive to Light
• Responsible for peripheral vision
• Bundled in groups of 30, 40 or 100 to nerves that transmit
image to the brain.
Mrs. Soumya. M 27

28. Difference betweem CONE cell and ROD cell
Property Cones Rods
Location In the fovea Outside the fovea
Resolution and visual
acuity
Large Small
Total number of
elements
5 million 120 million
Color sensitivity Yes No
Brightness sensitivity Small, for daylight
vision
Large, for night vision
Figure
Mrs. Soumya. M 28

29. Veins and Arteries
• Central Retinal Vein
• Branch Retinal Veins
• Central Retinal Artery
• Branch Retinal Arteries
• When occluded the retina turns pale and yellowish and lacks
oxygen.
Mrs. Soumya. M 29

30. The inner nervous layer
Is a hole located in
the center of the iris.
It helps to pass
the light into the
eye.
Pupil
Mrs. Soumya. M 30

31. Structures inside the eyeball
Mrs. Soumya. M 31
The lens and ciliary body
divide the eye into two
cavities.
The anterior cavity
The posterior cavity
Closely-packed concentric
columnar cells
Focuses image on the retina.

32. CAVITIES OF THE EYE
•ANTERIOR CAVITY- Both the anterior and posterior
chambers are located within the anterior cavity,
•POSTERIOR CAVITY-while the vitreous chamber is
located in the posterior cavity.
Mrs. Soumya. M 32

33. CHAMBERS OF THE EYE
• ANTERIOR- Between iris and cornea
• POSTERIOR- Between iris and lens
• VITREOUS- Located behind the lens and in front of the optic
nerve.
Mrs. Soumya. M 33

34. Contains aqueous
humor which is
secreted by ciliary
body
 Maintains shape
of anterior eye.
aqueous humor
constantly produced -
leaves eye through
canal that carries it to
bloodstream.
Anterior Chamber of Eye
Anterior
Chamber
Mrs. Soumya. M 34

35. Contains vitreous
humor
 Maintains shape of
posterior eye.
 Refracts light rays.
Is not constantly being
produced.
It is not become
replenished if some is
Lost.
Posterior Chamber of Eye
Posterior Chamber
Mrs. Soumya. M 35

36. The vitreous chamber is the
largest of the three
chambers and is located
behind the lens and in
front of the optic nerve.
This chamber is filled with
a thick, clear gel-like
substance called
the vitreous humor (also
vitreous body).
Vitreous Chamber of Eye
Vitreous Chamber
Mrs. Soumya. M 36

37. Aqueous and Vitreous Humor
• Aqueous Humor is the clear liquid in the anterior chamber
(front) of the eye.
• Aqueous humor is produced by the ciliary bodies and it
flows from the posterior chamber through the pupil into
the anterior chamber.
• Vitreous Humor is the clear gelatinous fluid in the
posterior chamber (back 2/3) of the eye.
• vitreous humour is derived from embryonic mesenchyme
cells, which degenerate after birth.
Mrs. Soumya. M 37

38. Flow of Aqueous Humor
 Secreted by the cilliary bodies into the posterior chamber (between the
iris and the lens).
 Flows from the posterior through the opening of the iris (pupil) into the
anterior chamber
 Then flows through the trabecular meshwork into the canal of
Schlemm
 Then flows through the aqueous veins unto the surface of the eye, where
is functions, in part, as a lubricant.
Mrs. Soumya. M 38

39. Tears
•Normal Tears
•Lubricant
•Protect from bacterial infections
•Contain an enzyme called lysozyme
•Reflect Tears
•Mostly water
•Back-up for irritation, emotions and dryness
Mrs. Soumya. M 39

40. Make-Up of Normal Tears
1. Mucin, which is a mucus like substance, produced by goblet cells
that help adhere the tears to the eye and are produced deep inside
the eyelids.
2. Water, which makes up about 90% of the tear, is produced by the
lacrimal glands located under the brow of the eye.
3. Fatty oils called lipids, which are the outside layer, slow down the
evaporation of the tears and are produced by the meibomian
glands on the edge of the eyelids.
Mrs. Soumya. M 40

41. Lacrimal gland
The lacrimal glands are the sites of tear
production.
Tears function to keep the
conjunctiva and corneal epithelium
moist and wash away foreign material
from the eye.
Accessory structures
Mrs. Soumya. M 41
Lacrimal apparatus
Secretes and drains tears from
the eye

42. Accessory structures
Mrs. Soumya. M 42
Eyelashes
Eyelashes are short hairs of eye that
may occur in double or triple rows.
They function to protect the eye
from debris.
Lashes may also have different
lengths and diameters to one
another.

43. Accessory structures
Mrs. Soumya. M 43
Conjunctiva
The conjunctiva refers to the lining of the
eye.
It has 2 parts
Palpebral conjunctiva
Bulbar conjunctiva
It helps lubricate the eye by secreting
mucous, and serves as a protective
barrier again microbes.
It contains many goblet cells which
secrete a component of the tears that
bath the eye.

44. Accessory structures
Mrs. Soumya. M 44
Eyelid
The main function of the eyelid
is to provide the eye with
protection. There are several
types of glands in the
eyelids, including tarsal glands
that produce a sebaceous
secretion that results in an oily
surface of the tear film to
prevent the evaporation of the
normal tear layer.

45. Accessory structures
Mrs. Soumya. M 45
Extraocular Muscles
i. Rectus dorsalis
ii. Rectus ventralis
iii. Rectus medialis
iv.Rectus lateralis
v. Obliqus dorsalis
vi.Obliqus ventralis

46. Functions of Extraocular Muscles
Mrs. Soumya. M 46
IO SR IO/SR SR/IO SR IO
LR MR MR LR
SO IR SO/LIR eft and IR/SO IR SO
Right.
 The remaining two mMR uscles coMRntrol the adjustments
involved in counter acting head movement.
CONVERGENCE
These six muscles responsible for eye movement.
 Four rectus muscles control the movement of the eye
in the four cardinal directions:
Up,
Down,

47. PHYSIOLOGY OF EYE
Mrs. Soumya. M 47

48. Visual Pathway
Mrs. Soumya. M 48
Pathway of LIGHT

49. + The Optic Pathway
 Begins at the optic nerve.
 Impulses cross and partially split at the optic
chiasm.
 After the chiasm, it becomes the optic tract.
 Lateral geniculate bodies (sensory way
stations)
 Some fibers go to the colliculus (located in
the mid brain)
 The other fibers fan out into the visual
cortex which is located at the top and back
of the brain.
Mrs. Soumya. M
49

50. +
The Brain and Vision (cont)
 Temporal Lobes
 center for visual learning
 recognition by sight
 Midbrain -- Limbic sector
 emotional responses to visual stimuli
 Midbrain -- Superior Colliculus --
 guides visual attention
Mrs. Soumya. M
50

51.  Refraction is the phenomenon w
possible by the eye as well as b
lenses.
hich makes image formation
y cameras and other systems of
 The eye, is optically equivalent to the usual photographic
camera.
 The lens system of the eye is composed of four refractive
interfaces.
 Formation of an Image on the Retina.
The lens system of the eye can focus an image on the retina.
The image is inverted and reversed with respect to the object.
However, the mind perceives objects in the upright position
because the brain is trained to consider an inverted image as the
normal.
Refraction
Mrs. Soumya. M 51

52. Accommodation
Mrs. Soumya. M 52
 The process of changing the
shape of the lens while
focusing on an object is
termed as accommodation.
 At rest focused on distant
objects, needs to increase
focal power than focus on
close objects.
 The ciliary muscles contract
and release tension in the
ligaments and the lens
becomes rounder in case of
close objects.

53. There are four types of photopigments, one in the rods and one in
each of three types of cones.
The pigment in the rods is called rhodopsin.
Rhodopsin absorbs all visible wavelengths, so that rods
provide vision only in shades of grey by detecting different
intensities rather than colours.
The three types of cones - red, green and blue
photopsin, can respond selectively to various
wavelengths of light, giving rise to colour vision.
Photopigments
Mrs. Soumya. M 53

54. Rhodopsin
Mrs. Soumya. M 54
ed by rhodopsin.
lecule tightly-packed in the
billion rhodopsin molecules,
um photon capture rate
 The photon is absorb
 The light receptor
mo disk membranes
 One rod contains 10
which ensures an optim
Rhodopsin has 2
components
Retinal- Vitamin A aldehyde
Opsin- single polypeptide
containing 7
transmembrane domains

55. Mrs. Soumya. M 55

56.  Vitamin A is present both in
the cytoplasm of the rods
and in the pigment layer of
the retina.
Therefore, vitamin A is
normally always available to
form new retinal when
needed.
 Conversely, when there is
excess retinal in the
retina, it is converted back
into vitamin A, thus reducing
the amount of light-sensitive
pigment in the retina.
 Night blindness.
Mrs. Soumya. M 56

57. The retina therefore signals the brain
Light stimulation through an inhibitory
response involving a series of
physiological reactions
Action potentials,
Only originate in the ganglion cells,
The first neurons in the chain that carry
the visual stimuli to the brain.
Vision occurs
This process is called
phototransduction.
Phototransduction
Mrs. Soumya. M 57

58. N
Mrs. Soumya. M 58
• Astigmatism– defective
curvature of the cornea
or lens of the eye.
• Presbyopia– impaired
vision of the cornea or
lens of the
eye, associated with
aging.
• Hyperopia– can’t see
close objects, rays of
light focus behind retina
• Myopia- can’t see far
away objects, rays of
light focus in front of the

59. The Miracle of Vision!
Mrs. Soumya. M 59

60. TEACHER’S REFERENCE
Tortora DJ. Principles of anatomy and
physiology.14th edition. England: John
Wiley and sons publication; 2014.
Mrs. Soumya. M 60

61. TEACHER’S REFERENCE
Mrs. Soumya. M 61
Ghosh BD. Human anatomy for
students: Jaypee publication ; 2007

62. STUDENT’S REFERENCE
Mrs. Soumya. M 62
Chauracia BD. Human Anatomy.
Volume 2.4th edition. New Delhi: CBS
publication; 2008.

63. STUDENT’S REFERENCE
Ashalatha PR. Text book of anatomy and
physiology for Nurses.2nd edition: Jaypee
publication; 2010.
Mrs. Soumya. M 63

64. STUDENT’S REFERENCE
Mrs. Soumya. M 64
Chauhan R. Anatomy for B.Sc.
Nursing: APC Publication; 2007.

65. What is the primary (most powerful)
focusing structure of the eye?
•cornea
Mrs. Soumya. M 65

66. Which type of photoreceptor is best able to
process bright light and color?
•CONE CELLS
Mrs. Soumya. M 66

67. Which eye structure determines a
person’s eye color?
•IRIS
Mrs. Soumya. M 67

68. Which eye structure is comparable to the
film of a camera because it senses light
focused on it?
•RETINA
Mrs. Soumya. M 68

69. What is the point of sharpest, most
distinct visual acuity within the eye?
•fovea centralis
Mrs. Soumya. M 69