Chapter041

Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

Timby/Smith: Introductory Medical-Surgical Nursing, 10/e

Timby/Smith: Introductory Medical-Surgical Nursing, 10/e

Chapter 41: Introduction to the Sensory System


Anatomy, Physiology of the Eye Anatomy, Physiology of the Eye

• Extraocular Structures

– Eyelids, eyelashes, tears: Protect the eye

– Canthus: Where eyelids meet; Usually horizontal; Down syndrome; Epicanthal fold

– Blinking: Clears dust, particles from eye surface

– Eyelids: Adjust amount of light entering eyes; Distribute tears; Multiple glands; Conjunctiva; Caruncle; Lacrimal apparatus

– Tears: Water, Sodium chloride, lysozyme


Anatomy, Physiology of the EyeAnatomy, Physiology of the Eye

Figure 41-1 External

structures of the eye and position of the lacrimal

structures


Intraocular StructuresIntraocular Structures• Three Layers

– Sclera (White of the eye)

• Protects structures within the eye

• Connects to cornea, anterior chamber, pupil

– Uvea (Vascular coat of the eye)

• Choroid; Iris; Pupil; Aqueous humor; Vitrous humor

– Retina

• Rods and cones; Macula


The EyeThe Eye

Figure 41-2 Three-dimensional cross-section of the eye


Visual FunctionVisual Function• Light Nerve signals: Interpreted in cerebral cortex

• Refraction; Rods, cones Optic nerve; Accommodation

• Near point; Cataract: Opaque lens, blurred, cloudy images

Figure 41-3 A normal opthalmoscopic picture. The fundus or back of the eye as seen through an ophthamoscope. The optic disc, with its radiating vasculature, is easily distinguished from the macula lutea.


Nursing AssessmentNursing Assessment• Client History

– Allergy; Vision changes; Discomfort; Corrective lenses

– Eye medications; Eye trauma, disease, surgery

– Family history of eye disease

• Physical Assessment

– Symmetry

– Inflammation; Exudate

– Pupil constriction


Eye Assessment Eye Assessment • Visual Screening Tests

– Snellen eye chart: Visual acuity

– Jaeger chart; Rosenbaum Pocket Vision Screener: Near vision

– Ishihara polychromatic plates: Color vision

• Extraocular Muscle Function

– Corneal light reflex test: Eye alignment

– Cover-uncover test: Extraocular muscle function

– Positions test: Eye muscle strength, cranial nerve function


Diagnostic StudiesDiagnostic Studies• Ophthalmoscopy: Examination of fundus

• Retinoscopy: Focusing power of each eye

• Tonometry: Intraocular pressure

– Normal IOP: 10 to 21 mm Hg

• Visual Field Examination

– Peripheral vision; Gaps

– Visual field change associations: Glaucoma; Stroke; Brain tumor; Retinal detachment

• Color Vision Testing: Color differentiation ability


Diagnostic StudiesDiagnostic Studies• Amsler Grid: Macular problems

• Slit-lamp Examination: Magnifies eye surface

– Identifies: Corneal abrasions; Iritis; Cataracts; Conjunctivitis

• Retinal Angiography: Vascular changes, blood flow

• Ultrasonography: Used when posterior of eye difficult to visualize

• Retinal Imaging: High-resolution; Pupil dilation unnecessary


Nursing ManagementNursing Management• Client Education

– Maintenance, preservation of eye function

• Obtain an Accurate Baseline

• Client Assessment for Further Action


Anatomy and Physiology of the Ear Anatomy and Physiology of the Ear • Subdivisions of the Ear: Outer; Middle; Inner

– Outer ear (Auricle)

• Pinna; External acoustic meatus; Tympanic membrane

– Middle ear

• Eustachian tubes; Malleus; Incus; Stapes

– Inner ear (Labyrinth)

• Cochlea (hearing); Semicircular canals (balance); Vestibulocochlear nerve (Cranial nerve VIII; Organ of Corti


Subdivisions of the EarSubdivisions of the Ear

Figure 41-8Diagram of the ear, showing the external, middle, and

internal subdivisions.


Ear AssessmentEar Assessment

• Basic Auditory Acuity Tests

– Whisper test: Gross auditory acuity

• Otoscopic Examination: External acoustic canal, tympanic membrane inspection

• Tuning Fork Tests

– Conductive or sensorineural hearing loss

– Rinne test; Weber test

• Romberg Test: Ability to sustain balance


Diagnostic StudiesDiagnostic Studies• Audiometry: Precise measurement of hearing

acuity; Measured in decibels (dB)

– Lowest perceptible sound perceived: 20 dB

– Painful sound level: 120 dB

• Caloric Stimulation Test Nystagmus

– Measures vestibular reflexes of inner ear

• Electronystagmography: Vestibular function

– Used in conjunction with caloric stimulation test

– Measures duration, velocity of eye movements during nystagmus


Nursing ManagementNursing Management

• Client Assessment: Ear structure; Hearing function

– Screening in healthcare settings

– Baseline for further testing, referral

– Client education: Maintenance of hearing function and testing


End of Presentation

Chapter041

Documents

eye copyright

eye tonometry

eye canthus

preservation of eye

eye surface eyelids

eye muscle strength

nystagmus copyright

balance copyright