Disorders Eye And Ear — Free NHRA Study Notes

DISORDERS of the EYE & EAR

🖼️ [Diagram]: A cross-section of the human eye showing the iris, pupil, sclera, cornea, lens, retina, and optic nerve. It highlights the main anatomical parts of the eye.

• secretes aqueous humor that helps give the eye its shape

3. IRIS

• the colored portion of the eye
• located in front of the lens
• it has a central opening called the pupil

INNER LAYER (RETINA)

• a thin, delicate structure in which the fibers of the optic nerve are distributed

Contains the following structures: CONES

• Specialized for fine discrimination, central vision & color vision
• Functions at bright levels of illumination RODS
• More sensitive to light than cones
• Aid in peripheral vision
• Functions at reduced levels of illumination

VISION

External Structures of The Eye EYELIDS & EYELASHES

• Protect the eye from foreign particles

LACRIMAL APPARATUS (LACRIMAL GLAND & ITS DUCTS AND PASSAGES)

• Produces tears to lubricate the eye & moisten the cornea
• Tears drain into nasolacrimal duct which empties into nasal cavity

Internal Structures of The Eye CONJUNCTIVA

• Pink; lines inner surface of eyelids & covers the eyeballs.

A. EYEBALL

LAYERS OF THE EYEBALL OUTER LAYER

• fibrous coat that supports the eye

1. SCLERAE

• "white of the eye"

2. CORNEA

• Transparent tissue through which light enters the eye.

MIDDLE LAYER

• second layer of the eyeball
• vascular & highly pigmented

1. CHOROID

• a dark brown membrane located between the sclera & the retina
• contains blood vessels that nourishes the retina

2. CILIARY BODY

• connects the choroids with the iris

B. FLUIDS OF THE EYE

1. AQUEOUS HUMOR

• Clear, watery fluid that fills the anterior & posterior chambers of the eye
• produced by the ciliary processes, & the fluid drains in the Canal of Schlemm
• contributes to maintenance of IOP

🖼️ [Diagram]: A detailed cross-section of the eye focusing on the aqueous humor production and outflow. It labels the cornea, Schlemm's canal, anterior chamber, trabecular meshwork, sclera, iris, posterior chamber, ciliary epithelium, ciliary muscle, and lens. It also includes arrows indicating the conventional and diffusional pathways of aqueous humor inflow and outflow, and the uveoscleral pathway of aqueous humor outflow.

2. VITREOUS HUMOR

• Clear, gelatinous/jell-like material that fill the posterior cavity of the eye
• Maintains the form & shape of the eye

C. VITREOUS BODY

• contains a gelatinous substance that occupies the vitreous chamber which is the space between the lens & retina

• transmits light & gives shape to the posterior eye

D. OPTIC DISK

• a creamy pink to white depressed area in the retina
• the optic nerve enters & exits the eyeball in this area
• Referred to as the "BLIND SPOT"
  • lack photoreceptors
  • insensitive to light

E. CANAL OF SCHLEMM

• a passageway that extends completely around the eye
• permits fluid to drain out of the eye into the systemic circulation so that a constant IOP is maintained

F. LENS

• A transparent circular structure behind the iris & in front of the vitreous body
• Bends rays of light so that the light falls on the retina

G. PUPILS

• Control the amount of light that enters the eye & reaches the retina
• Darkness produces dilation while light produces constriction

ASSESSMENT OF VISION

SNELLEN CHART

• simple tool to record visual acuity
• the client stands 20 ft from the chart & covers 1 eye and uses the other eye to read the line that appears more clearly
• this procedure is repeated for the other eye
• the findings are recorded as a comparison between what the client can read at 20 ft and the no. of feet normally required by an individual to read the same line EXAMPLE: 20/50
• The client is able to read at 20 ft from the chart what a healthy eye can read at 50 ft

COLOR VISION TEST

• Tests for color vision which involve picking nos. or letters out of a complex & colorful picture

ISHIHARA CHART

• consists of nos. that are composed of colored dots located within a circle of colored dots
• client is asked to read the nos. on the chart
• each eye is tested separately
• the test is sensitive for the diagnosis of red/green blindness but not
• effective for the detection of the discrimination of blue

PUPILS

• Normal: round & of equal size
• Increasing light causes pupillary constriction
• Decreasing light causes pupillary dilation
• the client is asked to look straight ahead while the examiner quickly
• brings a beam of light (penlight) in from the side & directs it onto the side
• Constriction of the eye is a direct response to the light shining into the eye;

DIAGNOSTIC TESTS FOR THE EYE

TONOMETRY

• the test is primarily used to assess for an increase in IOP and potential glaucoma
• NORMAL IOP: 8-21 mm Hg

NURSING CARE

• Each eye is anesthetized.
• The client is asked to stare forward at a point above the examiner's ear
• A flattened cone is brought in contact with the cornea
• The client is instructed to avoid rubbing the eye following the examination if the eye has been anesthetized

EYE DISORDERS

Dx tests

• Snellen chart – measure visual acuity
• Tonometry – measures IOP
• Opthalmoscope – to examine the interior structures
• Gonioscopy – measures the angle of the anterior chamber

Structural defects

• Myopia (nearsightedness) – image is focused in front of the lens
• Hyperopia (farsightedness) – image is focused behind the retina
• Presbyopia – farsightedness associated with aging
• Strabismus – squint or cross – eye
• Nystagmus – involuntary abnormal movement of one or both eyes; jerky movements
• Diplopia & ptosis – caused by trauma to the cranial nerves

Glaucoma

• Results from IIOP caused by an excessive accumulation of aqueous humor.

Types of glaucoma

• Acute (narrow or closed angle) glaucoma
  • Caused by ocular disease, injury, surgery
  • S/Sx (rapid increase of IOP)
    • Eye pain
    • Headache
    • Blurring of vision

• Pupillary dilatation & unresponsive to light

Chronic (open angle) glaucoma

Frequently develops in older people S/Sx

• Loss of peripheral vision (tunnel vision)
• Halo vision

Narrow angle glaucoma

🖼️ [Diagram]: Cross-section of a narrow-angle glaucoma eye showing the trabecular meshwork, Schlemm's canal, anterior chamber, iris, lens, zonular fibers, and ciliary processes. It illustrates the blocked flow due to a narrow angle.

Open angle glaucoma

🖼️ [Diagram]: Two diagrams illustrating open-angle glaucoma. The first shows an eye with a normal drainage angle, anterior chamber, iridocorneal angle, iris, posterior chamber, and lens. The second shows an eye with an open-angle glaucoma, highlighting the blocked trabecular meshwork and impaired fluid outflow compared to the normal anatomy. The diagram also shows changes in the optic nerve and pressure buildup. It also includes labeled parts like the cornea, ciliary body, vitreous cavity, and optic nerve. (MAYO FOUNDATION FOR MEDICAL EDUCATION AND RESEARCH. ALL RIGHTS RESERVED.)

1. Acute (narrow or closed angle) glaucoma Treatment Miotic agents

• Pilocarpine
• Carbachol Beta blockers
• Timolol maleate Carbonic anhydrase inhibitors
• Acetazolamide (DIAMOX) Iridectomy

2. Chronic (open angle) glaucoma Treatment Beta blockers Miotic agents Carbonic anhydrase inhibitors laser trabeculoplasty or trabeculectomy

Cataracts

• Opacity or clouding of the lens
• Senile cataract (95%)
• Trauma, toxic substances, congenital (5%) Early signs:
• Blurred vision
• Decreased color perception Late signs:
• Diplopia
• Reduced visual acuity progressing to blindness
• Clouded pupil progressing to milky-white appearance

PRE-OP NURSING CARE

• Instruct measures to prevent or decrease IOP
• Administer pre-op eye medications including mydriatics
  • Atropine
  • Tropicamide

POST-OP NURSING CARE

• Elevate the head of the bed 30-45 degrees
• Maintain an eye patch
• Use side rails for safety
• Avoid lifting objects over 15lbs.
• Use stool softener
• Avoid lying on operative side

RETINOBLASTOMA

Is a malignant tumor of the retina of the eye Causes:

• Congenital
• Unknown
• Genetic factors
• Occurs early in life about 6 weeks of age through preschool

Pathophysiology Causes & risk factors > tumor develops at the retina 1 > pupils appears white (cats eye) and strabismus 2> tumor metastasize to the optic nerve to the subarachnoid space & brain > metastasize to distant body such as bone marrow & liver > multiple organ failure > death

Clinical manifestations

• Cats eye reflex (whitish appearance of pupils)
• Strabismus (2nd most common sign)
• Orbital inflammation
• Hyphema (presence of blood in the anterior chamber of the eye)
• Fixed pupil

Diagnostic evaluation

• Ophthalmoscopy
• Skull x-ray
• CT scan/MRI
• Bone marrow aspiration

Treatment

• Cryosurgery (freezing the tumor to destroy local cells)
• Laser surgery
• Enucleation
• Chemotherapy/radiation therapy

Nursing interventions

• Emotional support to the parents
• Care during radiation therapy
• Sedate as prescribed
• Avoid exposure to the sun
• Apply non-irritating lubricant
• Administer meds at precise time
• Encouraging parents to seek genetic counseling
• Preop care
• Prepare child's for all diagnostic procedure
• Encourage parents participate child's needs to decrease anxiety
• Post op care
  • *change dressing and cleanse the operative site as ordered.

DETACHED RETINA

• A hole, tear, separation of the retina from the choroid.
• Accumulation of fluid in between the retina & epithelium Hallmark S/Sx
• Blackness in the visual field
• dark or light floating spots
• Sense of curtain being drawn

IMMEDIATE NURSING CARE

• Provide bedrest
• Cover both eyes with patches to prevent further detachment
• Avoid jerky head movements
• Prepare the client for surgical procedure as prescribed Surgical treatment of choice
• Scleral buckling to reattach the retina against the choroid.

EAR DISORDERS

🖼️ [Diagram]: A detailed cross-section of the human ear, showing the subdivisions: external, middle, and inner ear. Key structures labeled include the temporal bone, semicircular canals, ossicles (malleus, incus, stapes), vestibular nerve, facial nerve, cochlea, cochlear nerve, tympanic membrane, tympanic cavity, Eustachian tube, pinna, external auditory meatus, and internal auditory meatus.

HEARING

FUNCTIONS OF THE EAR

• Hearing
• Maintenance & balance

EXTERNAL EAR

• Embedded in the temporal bone bilaterally at the level of the eyes
• Extends from the auricle through the external canal to the tympanic membrane or eardrum
• Includes the mastoid process, a bony ridge located over the temporal bone

A. AURICLE (PINNA)

• Outer projection of ear composed of cartilage & covered by skin
• collects sound waves

B. EXTERNAL AUDITORY CANAL

• Lined with skin
• Glands secrete cerumen (wax)
• provides protection
• transmits sound waves to tympanic membrane

C. TYMPANIC MEMBRANE (EARDRUM)

• Located at the end of the external canal

• Vibrates in response to sound & transmit vibrations to middle ear

MIDDLE EAR

• Consists of the medial side of the tympanic membrane
• The tympanic membrane is a thick transparent sheet of
• tissue that provides a barrier between the external ear & the middle ear
• The middle ear is protected from the inner ear by the round & the oval window membranes
• The eustachian tube opens into the middle ear & allows for equalization of pressure on both sides of the tympanic membrane

A. OSSICLES

• Contains 3 small bones: Malleus (Hammer) attached to: tympanic membrane; Incus (Anvil); Stapes (Stirrup)
• Ossicles are set in motion by sound waves from to the footplate of the stapes in the oval window

OVAL WINDOW: an opening bet. the middle & inner ear

B. EUSTACHIAN TUBE

• Connects nasopharynx & middle ear
• Equalizes pressure on both sides of eardrum

INNER EAR

• Contains the semi-circular canals, the cochlea & the distal end of the 8th cranial nerve
• Maintains sense of balance & equilibrium

A. SEMI-CIRCULAR CANALS

• Contains fluid & hair cells connected to sensory nerve fibers of the vestibular portion of 8th cranial nerve

B.COCHLEA

• Spiral-shaped organ of hearing
• Connects organ of Corti, receptor and organ for hearing
• Transmits sound waves from the oval window & initiates nerve impulses carried by cranial nerve VIII (acoustic branch) to the brain (temporal lobe of cerebrum)

C. 8th CRANIAL NERVE

1. COCHLEAR BRANCH

• transmits neuro-impulses from the cochlea to the brain where it is interpreted as sound

2. VESTIBULAR BRANCH

• maintains balance & equilibrium

HEARING & EQUILIBRIUM

• The external ear conducts sound waves to the middle ear
• The middle ear also called the tympanic cavity conducts sound waves to the inner ear
• The middle ear is filled with air which is kept at atmospheric pressure by the opening of the eustachian tube
• The inner ear contains sensory receptors for sound & for equilibrium
• The receptors in the inner ear transmit sound waves & changes in body position to the nerve impulses

ASSESSMENT OF THE EAR

OTOSCOPIC EXAM

GUIDELINES

• The speculum is never blindly introduced into the external canal because of the risk of perforating the tympanic membrane
• tilt the head slightly away & hold the otoscope upside down as if it were a large pen
• this permits the examiner's hand to lie against the head for support
• pull the pinna up & back to straighten the external canal in an adult
• visualize the external canal while slowly inserting the speculum

NORMAL FINDINGS OF THE EXTERNAL CANAL

• Pink & intact without lesions
• Has various amounts of cerumen & fine little hairs

NORMAL FINDINGS OF THE TYMPANIC MEMBRANE

• The tympanic membrane should be intact without perforations & free from lesions
• The tympanic membrane is transparent, opaque, pearly gray & slightly concave

AUDITORY ASSESSMENT

• Sound is transmitted by air conduction & bone conduction
• Air is 2-3x longer than bone conduction

CATEGORIES OF HEARING LOSS

• Conductive
• Sensorineural
• Mixed Conductive & Sensorineural

CONDUCTIVE HEARING LOSS

• Due to any physical obstruction to the transmission of sound waves

SENSORINEURAL HEARING LOSS

• Due to a defect in the organ of hearing, in the 8th cranial nerve, or in the brain itself

MIXED CONDUCTIVE, SENSORINEURAL HEARING LOSS

• results in profound hearing loss

VOICE TEST

• Ask the client to block one external canal
• The examiner stands 1-2 ft away & quickly whispers a statement
• The client is asked to repeat the whispered statement
• Each ear is tested separately

WATCH TEST

• A ticking watch is used to test the high-frequency sounds
• The examiner holds a ticking watch about 5 inches from each ear & asks the client if the ticking is heard

TUNING FORK TESTS

A. WEBER TUNING FORK TEST

• Normal result: hearing the sound equally in both ears

FINDINGS

• If the client hears the sound louder in 1 ear,
• (+) LATERALIZATION is present
• applied to the side where the sound is heard the loudest

INTERPRETATION

• The finding may indicate the client has CONDUCTIVE HEARING LOSS in the ear to which the ear is lateralized
• The finding may indicate that there is a SENSORINEURAL HEARING LOSS in the opposite ear

B. RINNE TUNING FORK TEST

• Compares the client's hearing by air conduction & bone conduction

AIR CONDUCTION is 2-3X longer than BONE CONDUCTION

NORMAL RESULT: (+) RINNE TEST

• the client normally continues to hear the sound 2x louder in front of the pinna
• The examiner records the duration of both phases, bone conduction followed by air conduction and compares the times

FINDINGS

• If the client is unable to hear the sound through the ear in front of the pinna,
• (-) RINNE TEST
• Bone conduction is greater than air conduction

INTERPRETATION

• Client may have a CONDUCTIVE HEARING LOSS on the side tested
• The Rinne test is of no value in determining sensorineural hearing loss

VESTIBULAR ASSESSMENT OF THE EAR

TEST FOR FALLING

• The examiner asks the client to stand with the feet together & arms hanging loosely at the sides & eyes closed
• The client normally remains erect with slight swaying

ABNORMAL RESULT: (+) ROMBERG SIGN

• presence of significant swaying

Disturbance in the external & middle ear

1. CONDUCTIVE HEARING LOSS

• occurs when sound waves are blocked to the inner ear fibers because of external ear or middle ear disorders
• disorders can often be corrected with no damage to hearing, or minimal permanent hearing loss

CAUSES

• Any inflammatory process or obstruction of the external or middle ear
• Tumors
• Otosclerosis
• A build-up of scar tissue on the ossicles from previous middle ear surgery

CERUMEN & FOREIGN BODIES

CERUMEN/EAR WAX

• the most common cause of impacted canals

FOREIGN BODIES

• can include vegetables, beads, pencil erasers & insects

ASSESSMENT

• Sensation of fullness in the ear with or without hearing loss
• Pain, itching or bleeding

CERUMEN NURSING CARE

• Removal of the wax by irrigation is a slow process
• Irrigation is C/I in clients with a hx of tympanic membrane perforation
• To soften cerumen, add 3 gtts of glycerin to the ear @hs & 3 gtts of hydrogen peroxide BID
• After several days the ear is irrigated
• 50-70 ml of solution is the maximal amount a client can tolerate during an irrigation sitting

FOREIGN BODIES NURSING CARE

• If the foreign matter is vegetable, irrigation is used with care
• the material expends with hydration
• Insects are killed before removal unless they can be coaxed out by flashlight or a humming noise

• Mineral oil or alcohol is instilled to suffocate the insect which is then removed with ear forceps
• Use small ear forceps to remove the object & avoid pushing the object farther into the canal & damaging the tympanic membrane

EAR INFECTIONS

Otitis externa

• Also known as swimmers ear
• An infection of the external auditory canal & pinna.
• Usully bacterial in origin
• Pain is usually increased with movement of the movement of the pinna. Treatment
• Encourage oral fluids
• administer of analgesics or antipyretics

Otitis media

• Inflammation or infection of the middle ear cavity
• Common causes
  • Respiratory infection
  • Mostly happens in infants
  • Haemophilus influenza
  • Streptococci
  • Staphylococci Hallmark S/Sx
• Severe earache (otalgia)
• Mild hearing loss
• Feeling of fullness
• Fever
• Purulent discharge Key treatments
• Encourage oral fluids
• Teach the parents to feed infants in an upright position
• administer of analgesics or antipyretics
• administration of prescribed antibiotics

TYMPANOPLASTY

• a reconstruction of the middle ear may be attempted to improve
• conductive hearing loss

OTOSCLEROSIS

Overview:

• Fixation of the stapes caused by the growth of bone, preventing transmission of vibrations
• Cause unknown, but incidence higher in females; heredity a factor
  Clinical findings:
• Loss of hearing; ringing or buzzing in the ears
• presence of spongy bone in the labyrinth Therapeutic Interventions:
• Hearing aids to amplify sound
• Stapedectomy: removal of the diseased portion of the stapes, and replacement with a prosthetic implant to conduct vibrations from the middle to inner ear Nursing Care:
• History of onset and progression of symptoms
• Extent of hearing loss via audiometry
• Position postoperatively according to orders: lying on the operated side facilitates drainage: lying on the nonoperated side helps prevent displacement of graft
• Instruct the client to alter position gradually to prevent vertigo
• Instruct avoidance of sneezing, blowing nose, swimming, showering, and flying until permitted by physician; if the client must sneeze, instruct to keep mouth open to equalize pressure in ear

DISTURBANCES IN THE INNER EAR

SENSORINEURAL HEARING LOSS

• a pathological process of the inner ear or of sensory fibers that lead to the cerebral cortex
• is often permanent, & measures must be taken to reduce further damage or to attempt to amplify sound as a means of improving hearing to some degree

CAUSES

• Damage to the inner ear structures
• Damage to the cranial nerve VIII
• Prolonged exposure to loud noise
• Medications, trauma, infections, surgery
• Inherited disorders
• Metabolic & circulatory disorders
• Meniere's syndrome
• Diabetes mellitus
• Myxedema

MIXED HEARING LOSS

• also known as conductive-sensorineural hearing loss
• client has both sensorineural & conductive hearing loss

SIGNS OF HEARING LOSS

• Frequently asking people to repeat statements
• Straining to hear
• Turning head or leaning forward to favor one ear
• Shouting in conversations
• Ringing in the ears
• Failing to respond when not looking in the direction of the sound
• Answering questions incorrectly
• Raising the volume of the television or radio
• Avoiding large groups
• Better understanding of speech when in small groups

• Withdrawing from social interactions

MENIERE'S SYNDROME

• a syndrome also called ENDOLYMPHATIC HYDROPS
• overproduction or decreased reabsorption of endolymphatic fluid
• Triads
  • Tinnitus
  • Vertigo
  • Hearing loss
• a syndrome also called ENDOLYMPHATIC HYDROPS
• refers to dilation of the endolympathic system by either overproduction or decreased reabsorption of endolymphatic fluid
• characterized by tinnitus, unilateral sensorineural hearing loss, & vertigo
• symptoms occur in attacks & last for several days, & the client becomes totally incapacitated
• initial hearing loss is reversible, but as the frequency of attacks continues, hearing loss becomes permanent
• repeated damage to the cochlea caused by increased fluid pressure leads to the permanent hearing loss

CAUSES

• Any factor that increases endolymphatic secretion in the labyrinth
• Viral & bacterial infections
• Allergic reactions
• Biochemical disturbances
• Vascular disturbances producing changes in the microcirculation in the labyrinth

ASSESSMENT

• Feelings of fullness in the ear
• Tinnitus, as a continuous low-pitched roar or humming sound is present most of the time but worsens just before & during severe attacks
• Hearing loss is worse during an attack
• Vertigo
  • periods of whirling which might cause the client to fall to the ground
  • sometimes so intense that even when lying down, the client holds the bed or ground in an attempt to prevent the whirling
• Nausea & vomiting
• Nystagmus
• Severe headaches

NON-SURGICAL MANAGEMENT

• Preventing injury during vertigo attacks
• Providing bed rest in a quiet environment
• Provide assistance with walking
• Instruct the client to move the head slowly to prevent worsening of vertigo
• Initiate Na & fluid restrictions as Rx
• Instruct to avoid smoking
• Administer Nicotinic acid (Niacin) as Rx
  • promote vasodilating effect
• Administer antihistamines as Rx
  • reduce the production of histamine &
  • reduces inflammation
• Administer antiemetics as Rx
• Administer tranquilizers & sedatives as Rx
  • to calm client & allow rest, control the vertigo, N&V

SURGICAL MANAGEMENT

• performed when medical therapy is ineffective & the functional level of the client has decreased significantly

ENDOLYMPHATIC DRAINAGE & INSERTION OF THE SHUNT

• may be performed early in the course of the disease to assist with the drainage of excess fluids

RESECTION OF THE VESTIBULAR NERVE LABYRINTHECTOMY

• removal of the labyrinth may be performed

POST-OP NURSING CARE

• Assess packing & dressing on the ear
• Speak to the client on the side of the unaffected ear
• Perform neurological assessments
• Maintain side rails
• Assist with ambulating
• Encourage the use of bedside commode
• Administer antivertiginous& antiemetic medications as Rx

Key treatment

• Preventing injury during vertigo attacks
• Providing bed rest in a quiet environment
• Instruct the client to move the head slowly
• Initiate Na & fluid restrictions as Rx
• Diuretics as ordered.

EYE

Note: Mydriatics are a type of medicine that make the pupil of the eye dilate (open up). Mydriatics also tend to relax the focusing muscles of the eye, which means that blurred vision is a common side effect.