Adult 1 Vision and Hearing

Nursing interventions for Menier's disease

Minimize vertigo Patient Safety Patient Education Things to Avoid Precautions Medications Fluid Management

primary angle closure glaucoma

10 % of cases Angle closure reduces outflow of aqueous humor as a result of: Lens bulging Pupil dilation

primary open angle glaucoma

90 % of primary glaucoma Outflow of aqueous humor is decreased in the trabecular meshwork Drainage channels become clogged

Menier's Disease

Characterized by symptoms caused by inner ear disease including episodic vertigo, tinnitus, fluctuatng sensorineural hearing loss, and aural fullness Causes significant disability Onset between 30 and 60 Cause unknown

external ear

Auricle (pinna) - cartilage and connective tissue covered with epithelium External Auditory Canal - slightly S shaped tube about 1 inch in length Lined with hair, sebaceous and ceruminous glands serve to lubricate the canal, keep it free from debris, kill bacteria Inner half of the canal highly sensitize Functions to collect and transmit sound waves to the tympanic membrane

postoperative considerations

Bed rest Medication Management - topical agents, antibiotics, anti-inflammatory agents, or dilating agents Activity Recommendations Discharge Planning and Teaching

structure and function of lens

Biconex, avascular, transparent structure Located behind the iris Bends light rays so they fall into the retina Accommodation allows eye to focus on a near object via contraction of the ciliary body

Lens

Biconvex structure Located behind the iris and supported by small fibers called zonules Primary function is to bend light rays allowing the rays to fall on the retina Lens shape is modified by the ciliary zonules Results in accommodation - a process that allows focus on near objects such as reading via contraction of the ciliary body

hyperopia

Can see objects in the distance clearly Close objects are blurred

myopia

Can see objects nearly or near-sightedness Distance objects are blurred

astigmatism

Caused by unevenness in the cornea Results in visual distortion

middle ear

Cavity - air space located in the temporal bone Lined with mucous membranes continuous from the nasal pharnyx via the eustachian tube Eustachian tube functions to equalize atmospheric air pressure between the middle ear and the throat and allows the tympanic membrane to move freely Contains three tiny bones, malleus, incus, and stapes (ossicles) Vibrations of the typmanic membrane cause the ossicles to move and transmit sound to the oval window - causes fluid to move in inner and stimulate receptors of hearing Oval window also assists in maintaining fluid balance of the inner ear Epitympanum - superior part of the middle ear- communicates with air cells in the mastoid bone Facial Nerve (CN VII) crosses above the oval window in the middle ear

Structure and function of ciliary body

Ciliary muscles surround the lens, lie parallel to the sclera Ciliary zonules attach to lens capsule Ciliary processes lie behind iris and secrete aqueous humor

aqueous humor

Clear watery fluid Fills anterior and posterior chambers Produced by ciliary process Drains through the trabecular meshwork into the circulatory system Bathes and nourishes the lens and endothelium of the cornea Excess production or decreased outflow increases intraocular pressure

special assessment techniques

Color Vision Stereopsis - allows patients to see objects in 3 dimensions - loss causes impaired ability to judge distances Diagnostic Studies Refractometry Ultrasonography Fluorescein angiography Amsler Grid Test

inner ear

Composed of a bony labyrinth surrounding a membrane Cochlea - receptor organ for hearing Organ of Corti - tiny hair cells respond to stimulation Stimulus is converted and transmitted by the vestibulocochlear nerve to the temporal lobe in the brain to process and interpret as sound

sclera

Composed of collagen fibers meshed together to form an opaque structure "white" of the eye Helps protect intraocular structures

auditory system

Composed of peripheral auditory system and central auditory nerve systems Peripheral Auditory nerve system includes the external, middle and inner ear Concerned with reception and perception of sound

organ of balance

Composed of three semicircular canals - the membraneous labyrinth (housed within the bony labyrinth) Filled with endolymphatic fluid Bony labyrinth is filled with perilymphatic fluid Fluid cushions sensitive organs Communicate with the brain Debris, excessive pressure can cause disorders such as vertigo

lacrimal apparatus

Consists of glands and ducts, lacrimal canals and puncta, lacrimal sac and nasolacrimal duct Provide secretions to make up mucous, aqueous, and lipid layers of the tear film Tear film moistens eye and provides oxygen to the cornea

Collaborative management of Menier's Disease

Diagnostic tests to rule out CNS Disease Differential Diagnoses Glycerol test - improvement in hearing or speech discrimination supports a diagnosis

evaluation of glaucoma treatment

Expected Outcomes: Have no further loss of vision Comply with recommended therapy Safely function within own environment Obtain relief from pain associated with the disease and surgery

Structures and functions of vision

Eyeball Globe composed of 3 layers Sclera - tough outer layer and transparent cornea Uveal Tract - middle layer composed of iris, choroid, and ciliary body Retina - innermost layer

refractive media

For light to reach the retina - it must pass through the cornea, aqueous humor, lens and vitreous Must remain clear for light to reach the retina and stimulate photoreceptor cells Cornea is responsible for the majority of light refraction necessary for clear vision.

presbyopia

Form of hyperopia Occurs as a normal process of aging around age 40

Planning for glaucoma treatment

Goals of Treatment/ Management: Have no progression of visual impairment. Understand the disease process and rationale for therapy. Comply with all aspects of therapy (including medication administration and follow-up care). Have no postoperative complications.

nursing implications for glaucoma

Health Promotion - early detection, screenings Acute Intervention - immediate treatment, maximize comfort, post-operative care Ambulatory and Home Care - patient education in self-care management, environmental considerations

structure and function of choroid

Highly vascular Serves to nourish the ciliary body, iris, and outer portion of the retina Lies inside parallel to the sclera and extends from the area where the optic nerve enters the eye to the ciliary body

Hearing Assessment

Includes assessment of the vestibular (balance) system Problems with balance may manifest as: Nystagmus - abnormal eye movements observed as twitching, blurred vision Vertigo - sense that the person or objects around the person are moving or spinning - usually simulated by movement of the head Dizziness - sensation of being off balance - does not occur when lying down

secondary glaucoma

Increased IOP results from other systemic or ocular conditions that block outflow Inflammatory processes that block the outflow channels such as trauma or ocular neoplasms

risk factors of retinal detachment

Increasing Age Severe myopia Eye Trauma Retinopathy (diabetic) Cataract or glaucoma surgery Family or personal history

labrynthitis

Inflammation of the inner ear Affects cochlear/ vestibular portion of the labyrinth

Physical Examination

Initial Observation Visual Acuity Extraocular Muscle Function Pupil Function Intraocular Pressure Assessing structures - eyelids, eyebrows, eyelids, conjunctiva, sclera, cornea, iris, retina and optic nerve

structure and function of retina

Innermost layer of the eye Extends and forms the optic disk Neurons are the major portion Responsible for converting images into a form that the brain can understand and process as vision Composed a two types of photoreceptors Rods are simulated in dim or darkened environments Cones are receptive to colors in bright environments Fovea centralis - center of the retina - provides the sharpest visual acuity Macula - high concentration of cones - relatively free of blood vessels

IMPLANT

Intracorneal Ring Segments (ICRs) two semicircular pieces of plastic that are implanted between thel ayers of the cornea to treat mild forms of myopia designed to change the shape of the cornea by adjusting the focusing power. ICRs can be removed and the cornea will usually return to its original shape within a few weeks Refractive Intraocular Lens (REFRACTIVE IOL) For patients with a high degree of myopia or hyperopia. involves the removal of the patients natural lens and implantation of an IOL which is a small plastic lens to correct the patients refractive error Phakic Intraocular Lenses (phakic IOLs) sometimes reffered to as an implantable contact lens implanted into the eye without removing the yes natural lens used for patients with high degrees of myopia and hyperopia placed in front of the yes natural lens, leaving the natural lens in the eye preserves the ability of the eye to focus for reading vision

THERMAL PROCEDURES

Laser Thermal Keratoplasty (LTK) and Conductive Keratoplasty (CK) for patients with hyperopia or presbyopia. using laser or high radio frequency heat is applied to the peripheral area of the cornea to tighten it like a belt and make the central core steeper

posterior chambers

Lies between the anterior surface of the lens and the posterior surface of the iris Filled with aqueous humor which is secreted by the ciliary body

anterior chambers

Lies between the iris and the posterior surface of the cornea Filled with aqueous humor which is secreted by the ciliary body

treatment of chronic open angle glaucoma

Medications (Table 22-10 pg 434) Medications control but do not cure the disease Requires ongoing supervision and monitoring Argon Laser Trabuloplasty - reduces IOP approx 75% of the time Filtering Procedure - flap allows for aqueous humor to drain Implant - shunt aqueous humor into implanted resevoir

management of Menier's disease between attacks

Medications - diuretics, antihistamines, low-sodium diet Medications to reduce vertigo - Diazepam, meclizine, fentanyl with droperidol May require surgical intervention such as endolymphatic shunt surgery. Vestibular nerve resection to alleviate vertigo and preserve hearing

collaborative therapy of acute Menier's disease

Medications: antihistamines, anticholinergics, and benzodiazapines to decrease abnormal sensation, n/v Acute vertigo - treated symptomatically with bed rest, sedation, anti-emetics, anti-vertigo drugs Reassurance/ Counseling

glaucoma

Not one disease but a group of disorders characterized by: Increased intraocular pressure and the consequences of elevated pressure Optic nerve atrophy Peripheral visual field loss

treatment of acute angle closure glaucoma

Ocular emergency - requires immediate attention Miotics and oral/IV hyperosmotic agents to lower IOP Laser peripheral iridotomy or surgical iridotomy for long term care and prevention

Nursing assessment and diagnosis of Glaucoma

Patient's ability to understand and comply with the rationale and regimen Psychological reaction to the diagnosis Family involvement Self-care Activities Visual acuity, visual fields, IOP and fundus changes Risk for Injury Self-Care Deficits Acute Pain

Clinical manifestations of vision impairment

Photopsia (light flashes) Floaters "cobweb" or "hairnet" ring in field of vision Painless loss of peripheral or central vision Area of visual loss corresponds to the area of detachment

gerontologic considerations

Presbycusis hearing loss due to aging due to damage to the hair cells of the Organ of Corti or atrophy and lymph producing cells Sound transmission diminished by calcification of the ossicles Tinnitus - ringing in the ears

Collaborative Care for glaucoma

Primary focus is to keep the IOP low enough to prevent the patient from developing optic nerve damage. Damage is manifested by increasing visual field loss and progressive optic disc cupping.

eyebrow, eyelid, eyelashes

Protect the eye Serve as a physical barrier to dust and foreign particles Upper eyelid blinks spontaneously to distribute tears over the eyeball and control the amount of light entering the visual pathway Eyelids controlled via CN VII - facial nerve

structure and function of iris

Provides color of the eye Pupil - allows light to enter the eye Pupil constricts via the iris sphincter (CN III - oculomotor nerve) Pupil dilates via dilator muscle (CN V - trigeminal nerve)

Refractive errors

Refraction is the ability of light to bend light rays so that they fall on the retina Emmetropia - parallel light rays are focused through the lens into a sharp image on the retina Light that does not focus properly results in refractive errors

intraocular pressure

Regulated by the formation and reabsorption of aqueous humor Glaucoma is directly related to the balance or imbalance of this fluid Glaucoma is the 2nd leading cause of blindness in the US ( leading cause among African Americans) Incidence increases with age

Pathophysiology of Menier's Disease

Results in excessive accumulation of endolymph in the membranous labyrinth Causes the labyrinth to rupture Attacks may be preceded with a sense of fullness in the ear, increasing tinnitus, and a decrease in hearing acuity "drop attacks", whirling in space Autonomic symptoms - pallor, sweating, n/v Clinical course is highly variable Hearing loss is fluctuates and continuous attacks lead to progressive permanent hearing loss

causes of retinal detachment

Retinal Break - interuption in the full thickness of retinal tissue (tears or holes) Holes - occur spontaneously Tears - vitreous humor shrinks during age and pulls on the retina

Retinal Detachment

Separation of the sensory retina and the underlying pigment epithelium with fluid accumulation between the two layers 1 in 10,000 non-traumatic incidence per year More likely to occur in aphakic individuals Risk of retinal detachment in second eye is 2-25%

transmission of sound

Sound waves are conducted by air Strikes tympanic membrane causing it to vibrate - causes the mallus, incus and stapes to vibrate - to oval window - produces waves in the perilymph Once in the inner ear, sensory hair cells in the cochlea initiate nerve impulses transmitted to CN VIII and then to the brain

past medical history

Systemic Disease Diabetes, HTN, STD, AIDS, MS, etc... Cardiac or pulmonary diseases tx with Beta-Adrenergics Tests for visual acuity Medications Surgery of other treatments

Diagnostic studies of hearing

Tests for Hearing Acuity - whispered tests Tuning -Fork Tests - differentiates between conductive and sensorineural (Rinne and Weber Test) Audiometry - screening test for hearing acuity to determine the degree and type of hearing loss Screening Audiometry - pass / fail - baseline screening Pure-Tone Auditometry - determine hearing range

vitreous cavity

The anatomic space between the posterior lens and the retina Filled with vitreous humor - a gel subtance Light passing through vitreous may be blocked by non-transparent substances Vitreous becomes more liquid with aging

extra ocular muscles

Three pairs of extraocular muscles Superior and inferior rectus muscles Medial and lateral rectus muscles Superior and inferior oblique muscles

LEVELS OF VISUAL IMPAIRMENT

Total blindness devined as no light perception and no usable vision Functional Blindness patient has some light percenption but no usable vision almost all bliness in the US is the result of common eye diseases less than 4% is the result of injuries there are 1million people who are blind in the US most common cause of blindness: cataracts glaucoma age related macular degeneration diabetic retinopathy cornea diseases Legally Blind Individual meets the criteria developed by the federal government to determine eligibility for federal and state assistance and income tax benefits Partially Sigted INdividual not legally blind has a corrected visual acuity greater than 20/200 in the better eye greater than 20 degrees of visual field but the usual acuity is 20/50 or worse in the better eye

conjuctiva

Transparent mucous membrane Covers the inner surface of the eyelids and extends over the sclera Glands on the conjunctiva secrete mucous and tears

treatment options for Menier's disease

Unilateral involvement Results in loss of vestibular and hearing cochlear functions Labyrinthectomy -surgical ablation of the labyrinth

diagnostic studies of visual impairment

Visual acuity measurements - 1st diagnostic procedure Retinal detachment can be directly visualized Ultrasound if retina cannot be directly visualized

collaborative care for visual impairment

Visual acuity measurements - 1st diagnostic procedure Retinal detachment can be directly visualized Ultrasound if retina cannot be directly visualized Scleral Buckling - surgical procedure indenting the globe to seal retinal breaks and relieve inward traction on the retina Intraocular Procedures Pneumatic retinopexy Vitrectomy Proleferative vitreoretinopathy

CORNEAL MOLDING

also called orthokeratology use of specially designed rigid gas-permeable contact lenses to alter the shape of the cornea reduces or corrects myopia, and moderate degrees of astigmatism the cornea is molded by fitting progressively flatter rigid contact lenses and requires regular wearing of "retainer" contact lenses to maintain corneal shape.

UNCORRECTABLE VISUAL IMPAIRMENT

approximately 4.8 million people in the united states have severe visual impairment, which is defined as the inability to read newsprint even with glasses.

ASTIGMATISM

caused by an irregular corneal curvature irregularity causes the incoming light rays to be bent unequally the light rays do now ocome to a single point of focus on the retina can occur in conduction with any of the other refractive errors

APHAKIA

defined as the absence of the lens lens may be absent congenitally, or it may be removed during cataract surgery. a lens that is traumatically dislocated results in functional aphakia, although the lens still remains in the eye. the lens accounts for 30% of ocular refractive power the absence of the lens results in a significant refractive error without the focusing ability of the lens, images are projected behind the retina

HYPEROPIA

farsightedness causes light rays to focus behind the retina and requires the patient to use accommodation to focus the light rays on the retina fro near and far objects occurs when the conrea or lens does not have adequate focusing power or when the eyeball is too short

CONTACT LENSES

generally provide better vision than classes because the patient has more normal peripheral vision without the distortion and obstruction of glasses and their frames altered or decreased tear formation can complicate wearing contacts may be due to medications such as: antihistamines decongestants diuretics birth control pills and the hormones produced during pregnancy

LASER

laser assisted in situ keratomileusis (LASIK) may be considered for patients with low to moderately high amounts of myopia, hyperopia, and astigmatism involves using a surgical blade to create a thin flap in the cornea Photorefractive keratectomy (PRK) indicated for low to moderate amounts of myopia, hyperopia, and astigmatism. good option for patients with insufficient corneal thickness for a LASIK flap only epithelium is remove dand the laser sculpts the cornea to correct the refractive error.

SURGICAL CORRECTION OF REFRACTIVE ERRORS

laser surgery intraocular lens implantation thermal procedures

PRESBYOPIA

loss of visual focus accommodation due to aging generally appears around age 45 as the eye ages the lens becomes larger, firmer and less elastic there is an inability to focus on near objects

REFRACTIVE ERROR

most common visual problem defect that prevents light rays from converging into a single focus on the retina defects are a result of irregularities of the corneal curvature focusing power of thte lens or the length of the eye major symptom is Blurred Vision matient may also complain of ocular discomfort, eyestrain, or headaches

CORRECTIVE GLASSES

myopia, hyperopia, presbyopia, astigmatism, and aphasia can be modified by using an appropriate corrective lens. myopia requires minus corrective lens (concave) hyperopia, oresbyopia, and aphasia all require a plus corrective lens (convex) reading glasses are often for presbyopia presbyopic lenses can be combined to treat myopia and astigmatism the presbyopic lens is at the bottom of the bifocal or trifocal.

MYOPIA

nearsightedness most common refractive error 25% of americans exhibit this disorder Causes light rays to be focused in front of the retina may occur because of excessive light refraction by the cornea, or lens or because of an abnormally long eye there is an inability to compensate for objects at a distance

AMBLYOPIA

reduced vision due to refractive errors left uncorrected

cornea

transparent, avascular Refracts light rays to focus them on the retina Consists of 5 layers Epthelium Bowman's layer Stroma Descemet's membrane Endothelium