The EYE and the EAR

1
The EYE and the EAR

• The eye the ear are sense organs, like the
  skin, taste buds, and olfactory centers in the
  nose.

2
Outer Eye

• The conjunctiva is clear and colorless except
  when blood vessels are dilated. Dust and smoke
  will cause this and give the eye the bloodshot
  eye appearance.

Lacrimal caruncle
Conjunctiva
3
EYE

• A normal, healthy cornea is avascular (with no
  blood vessels) receives nourishment form blood
  vessels near its junction with the sclera. The
  function of the cornea is to bend or refract the
  rays of light.

4
The Inside of the Eye
Macula- yellowish region slightly near the optic
disk, contains the fovea.
The choroid is the middle, vascular dark membrane
of the eye, between the retina the sclera.
Is not constantly reformed, gives shape to eyeball
x
Aqueous Humor
Fovea- small cup-like depressed region is the
center point of clearest vision contains only
cone receptors

• The x shows where the blind spot called the
  optic disc is. It is where the nerve meets the
  retina. Contains only nerve fibers, no rods or
  cones.

5
Optic Chiasm

• Chiasm means crossing.
• Point at which fibers of the optic nerve cross in
  the brain.
• Notice that half of the visual field is projected
  to the other side of the brain.
• In the occipital lobe the images are fused to
  form a single image.

Fibers Cross over
Synapse in the Thalamus

6
Hemianopsia- Loss of vision in the contralateral
visual field.

• Contralateral means opposite.
• Damage to nerve cells in the right cerebral
  cortex such as in a stroke, will cause a loss of
  vision in the left visual field.
• Similarly, damage in the left cerebral cortex
  will cause a loss in the right visual field.

7
Sections of the Retina

• Cones- photoreceptor cells in the retina that are
  responsible for color central vision. 6.5
  million
• Three types of cones Red, Green Blue
• Rods -Photoreceptor cells of the retina that are
  essential for vision in dim light and peripheral
  vision. 120 million

• These cells relay info to the bipolar
  neurons, next to ganglion cells, and at last to
  the fibers of the optic nerve.

8
Normal Retina

• Intravenous injection of fluorescein (dye) to
  take photographs of the retina through the
  patients dilated pupils.
• Test shows blood flow in the retina, detects
  vascular changes for HBP and diabetes, and
  identifies lesions of the macular area.

• A normal fluoresein angiogram.

9
Detached Retina

• The two layers of the retina separate from each
  other.
• Trauma, head injuries, bleeding, infection, and
  shrinking of the vitreous humor can produce tears
  or holes result in separation of the retina.
• Treatment used might be photocoagulation to seal
  a hole, cryotherapy to burn a scar, and use of a
  scleral buckle.

• Patients often see bright flashes of light-
  (called photopsia) or black spots called floaters.

10
Scleral Buckling

• A procedure to repair retina detachment.
• A strip of sclera is resected, or a fold is made
  in the sclera.
• An implant is inserted with sutures to hold and
  buckle the sclera.
• A suture of silicon band pushes the two parts
  against each other to bring together the parts of
  the detached retina.

11
Nyctalopia- Retinitus Pigmentosa

• This is a genetic disorder where pigmented scars
  form on the retina and destroys retinal rods.
  Decreased vision and night blindness occurs.

12
Macular Degeneration

• Picture seen on left has normal vision. Picture
  on the right as it would appear to someone with
  macular degeneration.

• Progressive damage to the macula of the retina.
• Leading cause of blindness in the elderly.

13
Anisocoria

• Condition of uneven pupils.
• Indication of neurological injury or disease.

14
Lacrimal Tear Gland Ducts

• Dacryocystitis-inflammation of the tear sac

• Drainage of eye goes into the nose.

15
Blepharitis

• Inflammation of the eyelid

• Thickened lids with crusts around the lashes.

16
Hordeolum- stye, sty

• Localized, purulent, inflammatory staphylococcal
  infection of a sebaceous gland in the eyelid.

• Warm compress to the eye may help open up the
  gland.

17
Chalazion

• Small, hard, cystic mass on the eyelid
  (granuloma) Require incision and drainage.

• Formed as a result of chronic inflammation of a
  sebaceous gland along the margin of the eyelid.

18
Conjunctivitis

• Commonly called pinkeye.
• Inflammation of the conjunctiva which is the
  delicate membrane lining the eyelids and covering
  the anterior eyeball.

• Discharge of pus characteristic of highly
  contagious condition.

19
Blepharoptosis

• Drooping of the eyelid

20
Farsightedness- Hyperopia

• The eyeball shape is too short in the adult eye
  compared to normal or the lens is too weak.

• Convex lens used to correct.

21
Nearsightedness- Myopia

• The shape of the eyeball is too long for the
  adult eye compared to a normal eyeball or the
  lens is too strong.

• Corrected with a concave lens.

22
Astigmatism

• This causes light rays to be uneven and not
  sharply focused on the retina so that the image
  is distorted.
• The correction is with a cylindrical lens.

• Abnormal curvature of corneal surface or shape of
  the lens.

23
Radial Keratotomy (RK)

• Surgery in which spoke-like incisions are made to
  reshape the cornea, thus correcting
  nearsightedness.
• The first surgery was performed in Russia in
  1972. Introduced in U.S. in 1978.

• Shows location of the incisions.

24
Appearance of the Eye After Keratoplasty

• Also known as a Corneal Transplant.
• Surgical repair of the cornea results in this
  clinical appearance.
• This donor cornea is sutured into place after
  removal of the original cornea.

25
PKR- Photorefractive Keratectomy

• LASIK shapes the tissue below the surface of the
  cornea to reshape or flatten the corneal surface
  using an Excimer laser.

• The PKR removes tissue from the surface of the
  cornea.

26
LASIK

• Acronym for laser in situ keratomileusis (shaping
  the cornea)
• Performed as an outpatient under local
  anesthesia.
• The surgeon lifts the top of the layer of the
  cornea and uses a laser to sculpt the cornea.

• The the corneal flap is repositioned.
• Use of an Eximer Laser to correct refraction
  (myopia, hyperopia, and astigmatism) and lamellar
  keratoplasty.
• Differs from PKR because it shapes the corneal
  tissue beneath the surface as well as on the
  surface like in PKR.

27
Corneal Stem Transplants

• Can restore and maintain the clear covering of
  the cornea membrane that may have been destroyed
  by injury or disease.
• Stem cells are harvested from cadavers and
  transplanted into and around the edges of a blind
  recipient.
• This technique is in the research stages and has
  some problems with rejection the immune system.

28
Glaucoma

• Diagnosed by tonometry applied externally to the
  eye with a local anesthetic,
• Acute glaucoma has extreme ocular pain, blurred
  vision, redness of the eye, and dilation of the
  pupil. May cause blindness.
• Chronic glaucoma has no symptoms, only a gradual
  loss of vision.

Fluid leaves at the angle where cornea iris
meet.

• Glaucoma occurs when the circulation in the
  anterior chamber builds up and pressure builds.
• Treatment may be with drugs or with laser surgery.

29
Slit Lamp Microscopy

• Examination of anterior ocular structures under
  microscopic magnification.
• Devices attached to a slit lamp expand the scope
  of examination,

• Measuring intraocular pressure by tonometry to
  detect glaucoma.

30
Cataract

• A cataract is a type of degenerative eye disease.
• The protein in the lens clots clouds the
  vision.
• It is a gradual development of cloudiness within
  the lenses, not a film that covers the eye.

• The lens appear cloudy. Often can be seen by the
  naked eye.

31
Cataract Examples

• Snowflake cataracts are present at birth or
  others occur with complications from diabetes
  mellitus or from trauma.

• Senile cataracts are linked to the process of
  aging.

32
Cataract Surgery

• Phacoemulsification- technique of cataract
  extraction using ultrasonic vibrations to
  fragment (emulsify) the lens and aspirate it from
  the eye by use of an ultrasonic probe.

• The surgeon uses a small, self-sealing
  scleral-tunnel incision..
• In most patients, an intraocular lens is
  implanted at the same time.

33
Ophthalmoscopy

• Visual examination of the interior of the eye.
  The pupil is dilated and the physician shines the
  light into the back of the eye.

• Ophthalmoscope

34
Visual Acuity Vision Field Tests

• The Snellen chart assesses vision by reading a
  chart at a distance of 20 feet.
• Expressed as a ratio, such as 20/20 (1st tells
  distance, 2nd normal person could have read)

• Visual fields are examined by measuring the area
  within which objects are seen when the eyes are
  fixed, looking straight ahead without turning
  head.

35
Color Blindness

• People with normal vision will see the number 74.
  People with red-green color blindness cannot.
• Used to classify red-green if they see the 2
  only, the red sensitive cones are abnormal if
  they see the 4 only, the green sensitive cones
  are abnormal.

36
Anatomy of the EAR

• The two functions of the ear are to hear and to
  provide the sense of balance.

37
Inner Ear Middle Outer Ear
The eustachian tube or auditory tube leads to the
pharynx opens upon swallowing to reduce pressure
in the middle ear and keeps the eardrum from
bulging outward.
38
Eardrum- Tympanic Membrane

• A. Healthy tympanic membrane

• B. Tympanic membrane with a cholesteatoma (tumor
  of skin cells cholesterol).

Tympanic membrane is derived from the Greek word
for drum.
39
Eardrum- Tympanic Membrane

• D. Myringotomy with tympanostomy tube

• C. Acute Otitis Media (severe ear ache)

Placing tubes reduces the pressure.
40
Ossicles

• The tiny three bones of the middle ear pick up
  the vibrations of the eardrum and transfer the
  vibrations onto the inner ear through the oval
  window.
• Stapes is Latin for stirrup.

• The middle ear region.

41
Stapedectomy

• A prosthetic device (wire, Teflon, or metal) is
  placed into the incus and attached to a hole in
  the oval window.

• Using a microsurgical technique and a laser, the
  stapes bone is removed.

Malleus Incus
New device
Oval window
42
Inside the Cochlea

• This movement stimulates the hair cells on the
  organ of Corti to generate a nerve impulse.

• The vibrations of the oval window cause the
  perilymph in the bony labyrinth of the cochlea to
  move.

43
Cochlear Transplant

• If the hairs of the organ of Corti are damaged,
  nerve deafness occurs.
• A new surgically implanted device can improve
  this form of hearing loss.
• A transmitter outside the scalp sends sound info
  to a receiver behind the auricle which translates
  into an electrical code relayed to directly the
  cochlea and its nerve..

44
Acoustic Neuroma

• Benign tumor arising from the acoustic
  vestibulocochlear nerve (8th cranial nerve) in
  the brain.
• Causes tinnitus (ringing in the ears), vertigo
  (dizziness), and decreased hearing.

45
Meniere Disease

• Disorder of the labyrinth of the inner ear marked
  by elevated endolymph pressure within the cochlea
  and semicircular canals.
• Symptoms include, tinnitus, vertigo, nausea, and
  headaches. Attacks last for minutes or for hours.
• Cause is unknown an treatment is rest and drugs.

46
Audiometry

• Pure-tone audiometer

• lt One earphone emits a test sound while the
  other emits a masking noise.

47
Otoscopy- Visual examination of the ear with an
otoscope.

• The auricle (pinna) is pulled up and back. The
  hand holding the scope is placed against the face
  for stabilization.

• Ear thermometry using a tympanic membrane
  thermometer within 2 seconds.

48
The end

• Glaucoma- is Greek glaukos for blue-gray or sea
  green, means a morbid condition.
• Cataract- is derived from the Greek word for
  waterfall, as you would see things through a
  watery veil of mist or waterfall.

• Iris- special messenger of the Queen of Heaven
  according to Greek mythology. She passed from
  heaven to earth over the rainbow while dressed in
  rainbow hues.