1) The document provides an overview of disorders of the eye and ear, including anatomy, common conditions like glaucoma and tinnitus, and types of hearing loss. 2) It describes the anatomy of the eye and ear in detail. For the eye, it outlines the three layers and optical components. For the ear, it outlines the external, middle, and inner ear. 3) It discusses two main types of glaucoma - open angle and closed angle glaucoma. It provides details on symptoms, risk factors, pathophysiology, and differences between the two types.

1. Disorders of Special Senses
(Eye & Ear)
Unit-IV
Pathophysiology-II
By
Murad Ali
RN, GBSN, PGD Clinical Psychology, MSN Scholar

2. Objectives
At the completion of this unit learners will be able to:
• Review A & P of eye & ear
• Discuss some common visual & auditory
dysfunction
• Glaucoma
• Tinnitus & hearing Loss

3. Eye

4. Anatomy of the Eyeball
The adult eyeball measures about 2.5 cm (1 in.) in
diameter.
The eyeball consists of three layers:
1. Tunica fibrosa or Fibrous tunic (Sclera)
2. Tunica vasculosa or Vascular tunic (Choroid)
3. Tunica interna (Retina)

5. • Tunica Fibrosa
– It is tough outermost eyeball layer, divided into two
regions: the sclera and cornea
– Sclera—(scler=hard)—white of the eye; Covers
most of the eye surface, composed of collagen &
elastic fibers; optic nerve exits from sclera at the
back of eye.
– Cornea – is the anterior transparent region of
modified sclera that admits light into the eye.
– At the junction of sclera and cornea is an opening
called scleral venous sinus or canal of schlemm. A
fluid called aqueous humor drains into this sinus.

6. • The Optical Components
• The optical components of the eye are transparent
elements that admit light rays, refract (bend) them,
and focus images on the retina. They include the
cornea, aqueous humor, lens, and vitreous body.
• The aqueous humor is a serous fluid secreted by
the ciliary body into the posterior chamber, a space
between the lens and iris. It flows through the
pupil into the anterior chamber between the iris
and cornea. From here it is reabsorbed by a ring
like blood vessel called the scleral venous sinus or
canal of schlemm.

7. Production and Reabsorption of Aqueous Humor

9. Glaucoma
• Glaucoma is a state of elevated intra-ocular
pressure which is resulted by the accumulation
of aqueous humor when it is not reabsorbed as
fast as it is secreted.
• Glaucoma describes a group of diseases that kill
retinal ganglion cells.
• IOP is measured with tonometer.
• Tonometry provides an early detection.
• Normal range of IOP is 10-22 mm Hg

10. Classification of Glaucoma
I. Primary:
A. Congenital
B. Adult (common types)
1. Narrow angle
2. Open angle
II. Secondary
1. Inflammatory
2. Traumatic

11. Closed / Narrow Angle Glaucoma
• The anterior chamber is narrowed and outflow
becomes impaired when the iris thickens as a result
of pupillary dilation.
• The thickened iris restricts the aqueous flow from
posterior to anterior chamber and thus reduces or
eliminates the access to the iridocorneal angle to
allow its passage via the trabecular meshwork of
the canal of Schlemm.
• Closed angle glaucoma usually occurs as a result of
inherited anatomic defect that causes the anterior
chamber shallow.
• About 5% to 10% are closed angle glaucoma.

12. Narrow Angle Glaucoma
Symptoms
Severe eye/headache
pain
Blurred vision
Nausea and vomiting
Halos around lights
Intermittent eye ache
at night
Signs
Red, teary eye
Corneal edema
Closed angle
Mid-dilated, fixed
pupil

13. Open Angle Glaucoma
• Primary open angle glaucoma is the most common form of
glaucoma.
• It tends to manifest after the age of 35 years.
• IOP occurs in the absence of obstruction at iridocorneal angle.
So the angle is open and It is therefore called open angle
glaucoma.
• It usually occurs because of an abnormality of the trabecular
meshwork that controls the aqueous flow in the canal of
Schlemm.

14. Risk Factors of Open Angle Glaucoma
• 40 years age and above
• Family history ( if positive)
• DM
• CVD
• Topical corticosteroid moderate use
• Myopia
• IOP
• Gender

15. Open Angle Glaucoma
Symptoms
Usually none
May have loss of central
and peripheral vision
late
Signs
Elevated IOP
Visual field loss

16. What is the difference between open and closed-angle
glaucoma?
In open-angle glaucoma, the increase in pressure is often
small and slow. In closed-angle glaucoma, the increase
is often high and sudden

17. Pathophysiology
• The accumulation of aqueous humor elevates pressure in
the anterior chamber which compresses the canal of
Schlemm and causing a further reduction in aqueous
outflow.
• The elevated pressure in the anterior chamber drives lens
back and puts pressure on the vitreous body.
• The vitreous body presses the retina against the choroid
and compresses the blood vessels that nourish the retina.
• Impaired blood supply results in the death of retinal cells
and atrophy of optic nerve and thus ultimately in
blindness.
• Glaucoma leads to blindness if left untreated

18. Symptoms
• Symptoms often go unnoticed until the damage is
irreversible.
• In late stages, they include dimness of vision,
reduced visual field, and colored halo around
artificial lights.

19. A&P of Ear

20. Anatomy of the Ear
The ear has three regions:
• External ear
• Middle ear
• Inner ear
• The first two are concerned only with transmitting the sound
to the inner ear.

21. Internal Ear
• The internal ear is also called labyrinth because of its
series of canals.
• It consists of two main divisions.
Bony labyrinth.
Membranous labyrinth
• The bony labyrinth, a series of cavities and tubes in
the temporal bone, divides into three parts:
1) The semicircular canals,
2) the vestibule, both of them contain receptors for
equilibrium, and
3) the choclea (=snail), which contains receptors for
hearing.

22. Tinnitus
• Tinnitus is defined as sensations of hearing in the
absence of external sounds.
• Referred to as “ringing in the ears”.
• It may also be described as roaring, buzzing or
humming sound.
• May be unilateral or bilateral.
• Can be perceived inside or outside the ear.
• May be constant or intermittent.
• It is a symptom

23. • 1/3 of the population have had tinnitus at some stage in their
lives
• Up to 20% of the population currently experience tinnitus.
• Prevalence increases with age
• 80% of people don’t seek help
• 6-8% of those affected are severe

24. Division of Tinnitus
• Although it is subjective, yet it is divided into
objective and subjective for clinical purpose.
• Objective: It is a rare case in which the sound is
detected by another observer.
• Subjective: It refers to noise perception when
there is no noise stimulation of cochlea.

25. Pathophysiology
• Objective tinnitus is caused by vascular abnormalities
or neuromuscular disorders.
• In vascular disorders sounds are generated by
turbulent blood flow (like arterial bruits or venous
hums) which are conducted to the auditory system
producing a pulsatile type of tinnitus.
• The underlying physiologic mechanism of subjective
tinnitus is unclear. It seems likely that there are several
mechanisms including abnormal firing of auditory
receptors, abnormal cochlear neurotransmission
function or ionic imbalance, and alterations in central
processing of the signals.

26. Possible Causes
• Blow to the head
• Noise exposure
• Hypertension
• Stress
• Tumors
• Impacted cerumen
• Medication
• Infection
• Older age
• Meniere’s Disease (triad---- vertigo, tinnitus, hearing loss)
• Outer/Middle ear disease

27. Why is it worse at night?
• Distractions during the day make tinnitus less obvious.
• At night, when surroundings are quiet, tinnitus is more
obvious.
• Fatigue can also make tinnitus worse.

28. Hearing Disorders
The most common hearing disorders are those that
affect hearing sensitivity. When a sound is
presented to a listener with a hearing sensitivity
disorder, one of two things may occur:
1. The listener with a hearing sensitivity disorder
may be unable to detect the sound.
2. The sound will not be as loud to that listener as
it would be to a listener with normal hearing.

29. Hearing Loss
• Hearing is measured in decibels (db).
• Hard of hearing is defined as hearing loss greater
than 20 to 25 db in adults and greater than 15 db in
children.
• Hearing loss is qualified as mild, moderate, and
severe.
• Profound deafness is when hearing loss is greater
than 100 db or 75 db in children.
• Sounds over 80 decibels are considered hazardous
with prolonged exposure.

30. Types of Hearing Loss
• 1. Conductive Hearing Loss
• It occurs when auditory stimuli are not
adequately transmitted to via the auditory
canal, tympanic membrane, middle ear or
ossicle chain to the inner ear.
• Causes:
• External Ear conditions like:
• Impacted cerumen
• Otitis externa

31. Hearing Loss
• Middle Ear conditions
• Trauma
• Tumor
• Otitis media
• Otosclerosis

32. Hearing Loss
• 2. Sensorineural or Perceptive Hearing Loss
• It occurs with disorders that affect the inner ear,
auditory nerve, or auditory pathways of the brain.
• Tinnitus often accompanies cochlear nerve irritation.
• Causes
• Trauma----Head injury, Noise
• CNS infection-----meningitis
• Atherosclerosis
• Ototoxic drugs-----aminoglycosides, salicyclates, loop
diuretics, chloroquine, cisplatin
• Tumor
• Meniere’s disease

33. Hearing Loss
• 3. Mixed Hearing Loss
• It is the combination of both conductive and sensorineural hearing
loss.
• Causes
Colds, Earaches, Sinus problems, Allergies, Noise Exposures
Childhood Diseases, Medications, Head Trauma, Age

34. General info…
 The intensity of sound is
measured in units called
decibels .
 Any sounds over 80 decibels
are considered hazardous with
prolonged exposure.

35. Some ways to reduce it….
 Turn down the volume
on your stereo, TV,
headset on your
Walkman or CD player
 Wear earplugs if you’re
going to a loud concert
and while working
around loud noise such
as power tools,
jackhammers, and etc.
Get your hearing tested on a regular
basis

36. Physical Characteristics….
 Some people that are hearing impaired may wear a
hearing aid in or on the back of their ear
 Some people might have a deformed ear
 Some people might say some words differently

37. Mental Characteristics…
 They may feel that people who they talk to lose
patience with them because they have to repeat
themselves
 Hearing loss can create feelings of emotional
isolation
 A person may feel that the focus of attention is
placed on their disability and that they are not
recognized as anything other than a hearing impaired
person

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