1. BASIC ANATOMY
RFD 11104
THE EYE
NAME :
NOR ADIBAH BINTI MOHD 57179113018
LECTURER :
MDM BILQUES SULTANA

2. FACTS ABOUT EYE
The lens grows layers like an onion. As you get older, the lens becomes less
flexible because the buildup of layes compacts the center of the lens, making
it more rigid. When the lens becomes less flexible, it cannot change shape to
focus on things nearby.
The lense dense only about 20% of our focusing. The cornea does the other
80%. The lens changes shape so that you can focus on things that are near or
far away. The ciliary body controls the shape of the lens.
Cones are one type of photoreceptor cells in the retina. They are responsible
on daylight and colour vision.
Rods are the other type of photoreceptor cells. They respond to dim light.

3. FACTS ABOUT EYE continue
The fovea is a dimple in the retina where cones are concentrated and vision
is most accurate.
The aqueous humor is the clear fluid that helps the cornea keep its rounded
shape.
The fats that surrounds the eye is there for a reason. It helps cushion the eye
and protect it from the hard bone of the eye socket.
Each eyeball is held in position in the orbital cavity by various ligament,
muscles and facial expansions that surrounds it. The extraocular muscles
moves the eyeball in the orbits.
The blind spot is the area where the optic leaves the retina. Each eye has a
blind spot where they are no photoreceptor cells.
The eye has tiny blood vessels that carry blood to the retina.

4. STRUCTURE OF THE EYEBALL

5. ANATOMY OF THE EYE
CHOROID – The intermediate layer of the eye that is located underneath the
iris
CONJUNCTIVA – the mucous membrane that lines the inner surface of the
eyeball
CORNEA – the clear front window of the eye. It transmit and focuses light
into the eye
IRIS – the coloured part of the eye. It help regulate the light that enters the
eye
PUPIL – the dark center in the middle of the iris. The pupil determines how
much light is let in to the eye. It changes sizes to accommodate for the
amount of the light that is available
LENS – the transparent structure inside the eye that focuses light rays on to
the retina

6. ANATOMY OF THE EYE continue
RETINA – nerve layer that lines the back of the eye. The retina senses the light
and creates impulses that are sent through the optic nerve to the brain
MACULA – a small area in the retina that contains special light sensitive cells.
The macula allows us to see fine details clearly
OPTIC NERVE – the nerve that connects to the eye to the brain. The optic
nerve carries impulses formed by the retina to the brain, which interprets
them as images
SCLERA – the thick, tough, white outer that covering eyeball
VITREOUS – the clear, jelly-like substance that fills the middle eye. The
vitreous gives the eyeball its shape

7. Layers forming the wall of the
eyeball
Fibrous layer
Outside layer
Vascular layer
Middle layer
Sensory layer
Inside layer

8. Structure of the Eye: The Fibrous
Layer
SCLERA
White connective tissue layer
Seen anteriorly as the ―white of the eye
CORNEA
Transparent, central anterior portion
Allows for light to pass through
Repairs itself easily
The only human tissue that can be transplanted without
fear of rejection

9. Structure of the Eye: Vascular
Layer
Choroid is a blood - rich nutritive layer (posterior of eye)
Pigment prevents light from scattering
Modified anteriorly into two structures
Ciliary body—smooth muscle attached to lens
Iris—regulates amount of light entering eye
Pigmented layer that gives eye color
Pupil—rounded opening in the iris

10. Structure of the Eye: Sensory
Layer
Retina contains two layers
Outer pigmented layer
Inner neural layer
Contains receptor cells (photoreceptors)
Rods
Cones

11. Structure of the Eye: Sensory
Layer continue
Signals pass from photoreceptors via a two neuron chain
Bipolar neurons
Ganglion cells
Signals leave the retina toward the brain through the optic nerve
Optic disc (blind spot) is where the optic nerve leaves the eyeball
Cannot see images focused on the optic disc

14. Structure of the Eye: Sensory
Layer continue
Neurons of the retina and vision
Rods
Most are found towards the edges of the retina
Allow dim light vision and peripheral vision
All perception is in gray tones
Cones
Allow for detailed color vision
Densest in the center of the retina
Fovea centralis—area of the retina with only cones
No photoreceptor cells are at the optic disc, or blind spot

15. Structure of the Eye: Sensory
Layer continue
Cone sensitivity
Three types of cones
Different cones are
sensitive to different
wavelengths
Color blindness is the result
of the lack of one cone
type

16. Two segments, or chambers, of the
eye
Anterior (aqueous) segment
Anterior to the lens
Contains aqueous
humor
Posterior (vitreous) segment
Posterior to the lens
Contains vitreous
humor

17. Anterior Segment
Aqueous humor
Watery fluid found between lens and cornea
Similar to blood plasma
Helps maintain intraocular pressure
Provides nutrients for the lens and cornea
Reabsorbed into venous blood through the scleral venous
sinus, or canal of Schlemm

18. Posterior Segment
Vitreous humor
Gel-like substance posterior to the lens
Prevents the eye from collapsing
Helps maintain intraocular pressure

19. PATHWAY OF LIGHT THROUGH THE EYE
Light must be focused to a point on the retina for optimal vision.
The eye is set for a distance vision (over 20 feet away).
Image formed in the retina is a real image.
Real image are :
reversed from left to right
upside down
smaller than the object

21. VISUAL FIELD & VISUAL PATHWAY
Optic chiasma
Location where the optic nerves
cross
Fibers from the medial side of each
eye cross over to opposite side of
the brain
Optic tracts
Contain fibers from the lateral side
of the eye on the same side and the
medial side of the opposite eye

23. EYE REFLEXES
Internal muscles :
Controlled by the autonomic nervous system
Bright light causes pupils to constrict through action of
radial, circular, and ciliary muscles
Viewing close objects causes accommodation
External muscles :
Control eye movement to follow objects
Viewing close objects causes convergence (eyes moving
medially)

24. A CLOSER LOOK
Myopia (nearsighted) :
Distant objects appear blurry
Light from those objects fails to reach the retina and are focused in
front of it
Results from an eyeball that is too long

26. Hyperopia (farsighted) :
Near objects are blurry while distant objects are clear
Distant objects are focused behind the retina
Results from an eyeball that is too short or from a ―lazy lens‖

28. Homeostatic Imbalances of the
Eyes
Cataracs
Conjunctiva
Glaucoma
Hemianopia
Colour Blindness

29. CATARACTS—when lens becomes hard and opaque, our vision
becomes hazy and distorted

30. CONJUNCTIVITIS - it is pink eye and it is infection of the
conjunctiva (outermost layer of the eye that cover sclera). Easily
treated but contagious though normal contact.

31. GLAUCOMA—can cause blindness due to increasing pressure
within the eye

32. HEMIANOPIA—loss of the same side of the visual field of both
eyes; results from damage to the visual cortex on one side only

33. COLOR BLINDNESS — genetic conditions that result in the
inability to see certain colors
Due to the lack of one type of cone (partial color blindness)