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SPECIAL SENSES THE EYE

I. REVIEW OF ANATOMY AND PHYSIOLOGY

Figure 1: External Structure of the EyeSource: Brunner & Suddarths Textbook of Medical-Surgical Nursing (2009)

Parts:1. Eyeball or globe sits in a protective bony structure (orbit) surrounded

on three sides by the sinuses: ethmoid (medially), frontal (superiorly),and maxillary (inferiorly)

2. Eyelids - protect the anterior portion of the eye. With every blink ofthe eyes, the lids wash the cornea and conjunctiva with tears.3. Lacrimal glands produce tears (secreted in response to reflex or

emotional stimuli)

4. Conjunctiva - a mucous membrane, provides a barrier to the externalenvironment and nourishes the eye. The goblet cells of the conjunctivasecrete lubricating mucus. The bulbar conjunctiva covers the sclera,whereas the palpebral conjunctiva lines the inner surface of the upperand lower eyelids. The junction of the two portions is known as thefornix.

5. Sclera - helps to maintain the shape of the eyeball and protects theintraocular contents from trauma. The sclera may have a slightly bluishtinge in young children, a dull white color in adults, and a slightlyyellowish color in the elderly.

6. Cornea - main refracting surface of the eye7. Pupil part where light enters the eye. Its size is controlled by

pupillary muscle and sphincter

8. Iris - control how much light goes through the pupil (lets light enter theeye); highly vascular

Figure 2: Internal Structure of the EyeSource: Childrens Hospital Boston (www.childrenshospital.org)

9. Lens accomodation (focus & refocus); continues to grow throughoutlife, laying down fibers in concentric rings. This gradual thickening

becomes evident in the fifth decade of life and eventually results in anincreasingly dense core or nucleus, which can limit accommodativepowers.

10.Vitreous humor filled with a clear, jelly-like material; forms twothirds of the eye's volume and gives the eye its shape (posterior to thelens); shrinks & shifts w/age

11.Anterior chamber - the space between the cornea and the iris. Thisspace is filled with aqueous humor (a special transparent fluid rel. toIOP produced in ciliary body) that nourishes the eye (cornea) and keepsit healthy (open angle glaucoma)

12.Retina takes the light the eye receives and changes it into nervesignals to the brain

Two important layers of the retina

Retinal pigment epithelium (RPE) - A single layer of cells constitutesthe RPE, and these cells have numerous functions, including theabsorption of light.

Sensory retina - contains the photoreceptor cells: Rods are mainlyresponsible for night vision whereas the cones provide the best visionfor bright light, color vision, and fine detail. Cones are distributed


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Manifestations Aching eyes Blurred vision of close objects Crossed eyes (strabismus) in children Eye strain Headache while readingTreatment

easily corrected with convex lenses LASIK

c. Astigmatism - condition wherein the cornea is abnormally curved,causing vision to be out of focus; optical condition whereby theimage is distorted (angular distortion)

Causes, incidence, and risk factors The cause is unknown sometimes occurs after certain types of eye surgery (ie. cataract

surgery)

Diagnostics: refraction test retinoscopy - Children or others who cannot respond to a normal

refraction test can have their refraction measured by a test that usesreflected light

Symptoms difficulty in seeing fine details, either close up or from a distance the images seen may be blurryTreatment Mild astigmatism may not need to be corrected Glasses or contact lenses LASIK

Summary:

Colleen C. Flores, RN

Figure 3: Refractive Errors

Source: Childrens Hospital Boston (www.childrenshospital.org)

d. Presbyopia a condition in which the lens of the eye loses its ability tofocus, making it difficult to see objects up close

Causes, incidence, and risk factors age 45 and aboveManifestations Decreased focusing ability for near objects Eyestrain HeadacheDiagnostics general eye examination - Examination of the retina Refraction test - Slit-lamp test Visual acuity


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Treatment NO CURE but it can be corrected with glasses or contact lenses

(bifocals) With the use of contact lenses, some people choose to correct one eye

for near and one eye for far vision (monovision); it eliminates the needfor bifocals or reading glasses, but it can affect depth perception

3. BLINDNESS AND VISION LOSS Blindness is the inability to see; lack of vision loss of vision that cannot be corrected with glasses or contact lenses

a. Partial blindness - very limited vision.b. Complete blindness - cannot see anything and do not see l ightc. Legal blindness - vision worse than 20/200

Causes, incidence, and risk factors leading causes of chronic blindness:

a. cataractb. glaucomac. age-related macular degenerationd. corneal opacitiese. diabetic retinopathyf. eye conditions in children (e.g. caused by vitamin A deficiency)

Accidents or injuries to the surface of the eye (ie. chemical burns orsports injuries)

Diabetes Other causes: Blocked blood vessels; Complications of premature birth

(retrolental fibroplasia); Complications of eye surgery; Lazy eye; Opticneuritis; stroke; tumors

Manifestations:The type of partial vision loss may differ, depending on the cause: Cataracts - vision may be cloudy or fuzzy, and there may be problems

seeing shapes Diabetes - vision may be blurred, there may be shadows or missing

areas of vision, and difficulty seeing at night Glaucoma - there may be tunnel vision and blurry vision Macular degeneration - the side vision is normal but the central vision

is slowly lost

Managementa. Home care - the kind of home assistance will depend on type of vision

loss

b. Instruct the client and relatives to always keep certain items in thesame drawer, cabinet, table, or counter space.

c. Instruct client to learn to recognize the shape of certain items (ie. eggcontainers or cereal boxes)

d. Instruct the client and relatives to use plastic rings to hold pairs ofsocks together, whether washing, drying, or storing them

e. Client may learn Braillef. Instruct the relatives to use a phone with large numbers and instruct

client to memorize the keypadg. Instruct the client to fold different types of paper money in a differentway. For example, you can fold a $10 bill in half or double fold a $20bill.

h. If possible, learn to use a long white cane to help client get around onhis own

i. When walking with someone else's help, grasp their arm just above theelbow. Walk slightly behind them to follow their motions.

j. Ensure safety of the client4. CATARACT - an opacity of the lens that distorts the image projected to

the retina; painless; of unknown cause

Diagnostics1. Snellen chart for visual acuity2. ophthalmoscopy3. slit-lamp

Risk factors Aging, DM, Toxic factors, aging, family historyCommon Causesa. Age Related CataractLens water loss and fiber compaction

b. Traumatic CataractBlunt injury to the eye or head

Penetrating eye injury

Intraocular foreign body

Radiation exposure, therapy

Eye surgery

Types:a. Senile Cataract - age-related cataracts are defined by their location in

the lens: nuclear, cortical, and posterior subcapsular


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b. Nuclear cataract - associated with myopia (ie, nearsightedness), whichworsens when the cataract progresses

c. Cortical cataract - involves the anterior or posterior parts of the lensd. Posterior subcapsular cataracts - occur in front of the posterior

capsule; the eye is increasingly sensitive to glare from bright light (eg,sunlight, headlights).

Manifestations

cataracts develop slowly and painlessly Mild clouding of the lens often occurs after age 60, but it may notcause any vision problems

By age 75, most people have cataracts that affect their vision Visual changes:

a. Being sensitive to glareb. Cloudy, fuzzy, foggy, or filmy visionc. Difficulty seeing at night or in dim lightd. Double visione. Loss of color intensityf. Problems seeing shapes against a background or the difference

between shades of colors

g. Seeing halos around lights Frequent changes in eyeglass prescriptionManagement SURGERY ONLY CURE Better eyeglasses Better lighting Magnifying lenses SunglassesOperative Measures: Cataract surgery- intracapsular extraction,extracapsular extraction, phaecoemulsification and lens replacement

a. Intracapsular cataract extraction (ICCE) - involves the removal of thelens and the surrounding lens capsule in one piece; has a relatively highrate of complications due to the large incision required and pressureplaced on the vitreous body. Disadvantages: large incision (>10mm); requires sutures; risk for

retinal detachment & result in the loss of supportive structure forthe intraocular lens implant

b. Conventional extracapsular cataract extraction (ECCE) - involvesmanual expression of the lens through a small (usually 5-6mm or less)incision made in the cornea or sclera; self-sealing

c. Phacoemulsion used of sound waves to break cataractous lens intosmall pieces

Preoperative care for cataract surgery1) Teach about the nature, progression & treatment2) Orient the client to the staff and physical environment if both eyes will

be covered after surgery3) Series of ophthalmic drugs are instilled to dilate pupils & for

vasoconstriction (every 10 minutes for 4 doses at least 1 hour beforesurgery; additional dilating drops may be administered in the operatingroom

4) induce paralysis to prevent lens movementPost-operative care for cataract surgery POSITION: Place patient side lying on the UNAFFECTED side AVOID ACTIVITIES THAT INCREASE IOP:

1) bending from the waist2) sneezing &coughing; blowing the nose3) straining4) Vomiting5)

wearing tight shirt collars6) sexual intercourse

Prevent accidental rubbing or poking of the eye (eyepatch); removedafter the first follow-up appointment

Advise to wear glass x 24 hours or metal shield nightly x 1-4 weeks Sunglasses should be worn while outdoors (eye is sensitive to light) Slight morning discharge, some redness, and a scratchy feeling may be

expected for a few days (use a clean, damp washcloth to remove slightmorning eye discharge.

Notify the surgeon if new floaters (ie, dots) in vision, flashing lights,decrease in vision, pain, or increase in redness occurs

Patients may experience blurring of vision for several days to weeks.Vision gradually improves as the eye heals

Administer pain medication, topical antibiotics and anti-inflammatoryagents

Complications for both ICCE and ECCE:1) Pain early after surgery - IOP & hemorrhage2) Infection yellow or greenish drainage3) Bleeding into the anterior chamber5. GLAUCOMA refers to a group of eye conditions that lead to damage to

the optic nerve, the nerve that carries visual information from the eyeto the brain


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c) eye drops for muscle relaxation, minimize scarring andinflammation

3) Selective Laser Trabeculoplasty - treats specific cells selectively,leaving untreated portions of the trabecular meshwork intact; used forthe treatment of primary open angle glaucoma

4) Argon Laser Trabeculoplasty - laser beam opens the fluid channels ofthe eye, helping the drainage system work better; used for thetreatment of primary open angle glaucoma

5) Neodymium: YAG laser cyclophotocoagulation (YAG CP) - a last resortprocedure to save an eye from severe glaucoma damage not beingmanaged by standard glaucoma surgery; destroys part of the ciliarybody

Pharmacologic - initial IOP target = 30% lower than the current pressureTable 1: Medications(Brunner and Suddarth, 2009)

Medication Action Side EffectsNursingResponsibilities

Cholinergics miotics

(pilocarpine,carbachol)

Increases aq.Fluid outflowby constriction

of pupils &opening oftrabecularmeshwork

Blurry vision (esp.

in the dark);periorbital pain

Caution clients

in dimly litareas

Adrenergicagonists(dipivefrin,epinephrine

Reduces aq.Humorproduction &increaseoutflow

Eye redness; mayhave systemiceffects (ie.palpitations, HPN,headache)

Teach punctualocclusion tolimit systemiceffects

-blockers(timolol,betaxolol)

Decrease aq.Humorproduction

Systemic effects(ie. bradycardia,hypotension)

CI: asthma,COPD,

Carbonicanhydraseinhibitors(acetazolamide,methazolamide,dorzolamide topical form)

Decrease aq.Humorproduction

AE = anaphylacticreactions;depression;electrolyte loss; GIupset; impotence

CI: sulfaallergieselectrolytelevels

Prostaglandinanalogs(latanoprost)

Increasesoutflow

Conjunctivalredness; possiblerash

Instruct toreport any SE

6. Retinal detachment - separation of RPE from sensory layerTypes

a. Rhegmatogenous detachment - most common form; a hole or teardevelops in the sensory retina, allowing some of the liquid vitreousto seep through the sensory retina and detach it from the RPE; Thistype of retinal detachment represents an emergency, and surgeryis typically scheduled urgently (within 24 hours of diagnosis).

Risk factors: myopia, aphakia after cataract surgery, traumab. Traction retinal detachment froma pulling force on the retina;

most common in the advanced stages of diabetic retinopathy Risk factors: diabetic retinopathy, vitreous hemorrhage, or the

retinopathy of prematurity

c. Exudative retinal detachments - the result of the production of aserous fluid under the retina from the choroid. Risk factors: conditions that disturb the blood-retinal barrier (ie.

conditions that allow the build-up of fluid beneath the retina;inflammatory conditions such as Vogt-Koyanagi-Harada syndrome,collagen-vascular diseases, and posterior scleritis

Other conditions: tumors of the eye (e.g.,choroidal melanoma),congenital abnormalities (e.g., Coat's syndrome), andnanophthalmos (extremely small eyes)

DiagnosticsVisual acuity testingIndirect opthalmoscopyGoldmann three-mirror examinationManifestations: Separation of the retina from the epithelium Onset : sudden and painless (no pain fibers at the retina) Photopsia Initial detachment is usually partial describe as the sensation of a

curtain being pulled over part of the visual fields Bright flashes of light, especially in peripheral vision Blurred vision Floaters in the eye Shadow or blindness in a part of the visual field of one eyeManagement1) Cryotherapy (freezing probe) - cause the same adhesions, or scarring,

around the tear, thereby sealing the tear2) Photocoagulation (laser)


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3) Scleral Buckling - gently pushes the eye wall up against the retina Repair of the underlying structure A small piece of silicone is placed against the sclera & held in place

by encircling band (a gas or silicone oil placed inside the eye canbe used to promote retinal detachment (keeps the retina in contactwith the choroids & sclera)

4) Vitrectomy to remove gel or scar tissue pulling on the retina, used forthe largest tears and detachments (for tractional retinal detachments)

Nursing Management Mainly client education and supportive care (comfort) If gas bubble is used prone or lateral position Inform of possible complications:

Increased IOP Development of cataracts Post-op infections

7. Macular Degeneration - most common cause of visual loss in peopleolder than age 60

Types

a. Dry/Nonexudative - outer layers of the retina slowly break down; NOknown treatmentb. Wet/Exudative acute onset; proliferation of abnormal blood vessels

growing under the retina (within the choroid) = choroidalneovascularization

Manifestations Drusen (if outside the macula = asymptomatic) Gradual vision loss (central)Management Photodynamic therapy - a diode laser is used to treat the abnormal

network of vessels using a dye (verteporfin)Pre-op care

Instruct client to bring dark sunglasses, wide-brimmed hat, gloves,long-sleeved shirt; & slacks

Post-op care

Avoid bright lights or direct sunlight for 5days (ordinary indoor light isokay)

8. Trauma to the Eyes and related structuresPenetrating eye injuries*Requires surgeryBed rest with BP for 1 to 2 days

9. Intraocular Foreign BodyWash hands thoroughly before touching the eyes*Immediate copious flushing of the eye with water*if foreign body is lodged into the cornea, see a physician*avoid pressure on the eye, do not touch and rub*cover with dressing*consult an ophthalmologist immediately

SPECIAL SENSES THE EAR

Figure 5: Structure of the EarSource: Brunner & Suddarths Textbook of Medical-Surgical Nursing (2008)

Structure: 3 Divisions1. external ear 2. middle ear 3. inner ear

PartsEXTERNAL EAR - curved about 2.5 cm long in adult and ends at thetympanic membrane- attached to the head by skin and cartilage at about a 10 degree angle;

adult - 1 to 1 inches (2.5 - 3.75 cm)- covered with skin that has many fine hairs, glands and nerve endings- develops in embryo at the same time as the kidneys and urinary tract.


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1. Auricle or Pinna - composed of cartilage covered by skin; embedded inthe temporal bone on both sides of the head at the level of the eyes

2. Tympanic membrane or ear drum - a thick transparent sheet of tissueproviding a barrier between the external ear and the middle ear

- Follicles and cerumen - protect the ear drum and middle earMIDDLE EAR - begins at medial side of the ear drum that starts at thetympanic membrane

1. Ossicles of the middle ear (sound transmission)a. malleus hammer (most easily seen)b. incus anvilc. stapes - stirrups

2. eustachian tube -connects the middle ear to the nasopharynx;stabilizes the air pressure between the external atmosphere andmiddle ear

INNER EAR - lies on the other side of the oval window1. Semicircular canals - these are tubes made of cartilage that contains

air cells and fluid; connected to sensory fibers of the vestibular portionof the 8th cranial nerve; the organs of equilibrium

2. Cochlea - the spiral organ of hearing essential for sound transmissionand hearing

3. Vestibulea. Endolymph - a fluid similar to intracellular fluidb. Perilymph

Assessment History Demographic data Family history and genetic risk - health problems causing changes of

blood supply into the ear (heart diease, HPN, and DM)

Personal history ear trauma ear surgery past infection excessive cerumen ear itch any invasive instrument routinely used to clean the ear type and pattern of ear hygiene exposure to loud and noise music air travel swimming habits and protection when swimming

vitiligo smoking vitamin B12 and folate deficiency ototoxic drugs

Diagnostics1. Otoscope - Direct inspection of the ear2. Audiometry - measurement of hearing acuity

a. Pure tone - generated by an audiometer to determine hearingacuity Frequency - expressed in hertz Intensity - expressed in decibels Threshold - lowest level of intensity at which pure tones and

speech are heard by a clientb. Speech Audiometry - checks the clients ability to hear spoken

words; measured through a microphone connected to anaudiometer

3. Voice test - simple hearing acuity test4. Rinne Test - compares air conduction from bone conduction5. Webers Test - to assess bone conduction by testing the lateralization

(sideward transmission) of sounds process6. Electronystagmography (ENG) - a study used to clinically evaluate

patients with dizziness, vertigo, or balance dysfunction; provides anobjective assessment of the oculomotor and vestibular systems

Treatment Modalities1. Tympanoplasty - reconstructs the middle ear to improve hearing caused

by conductive hearing loss; varies from simple reconstruction of theeardrum (myringoplasty) to replacement of the ossicles within theeardrum

2. Myringotomy - a surgical procedure where a small incision is made inthe tympanic membrane (eardrum), typically in both ears. Small plastictubes (typanostomy tubes), open at both ends, are then inserted intothe incisions; allow fluid to drain out of the middle ear, which preventspressure from building up

3. Ossiculoplasty - involves ossicular reconstruction4. Stapedectomy - Surgical removal of the stape followed by replacement

with prosthesis5. Stapedotomy - Use of laser to create a hole in the footplate of the

stapes and prosthesis is place in the hole6. Labyrinthectomy - Surgical removal of the membranous labyrinth thru

the oval window or thru the mastoid bone


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Common Disordersa. Otitis externa - Painful condition cause when irritating or infective

agents (bacteria or fungi) come into contact with the skin of theexternal ear

Manifestations: Pain, skin is red, swollen, and tender to touchManagement: focused on reducing inflammation and promote comfort Topical or liquid otic antibiotics (Burows solution) Instillation of eardrops Analgesics for the 1st 48-92hrsb. Otitis media - acute infection of the middle ear, usually lasting less

than 6 weeksCausative agents: Streptococcus pneumoniae, Haemophilus influenzae,and Moraxella catarrhalis

Diagnosticsa. assess for pain with or without movement of the external earb. otoscopic examinationc. cultures of drainageManifestations vary with the severity- otalgia - unilateral- ottorhea - fever- erythematous tympanic membrane - hearing lossManagement otic antibiotics analgesics antihistamines and decongestant myringotomy or tympanotomyc. Mastoiditis infection of mastoid cells by untreated otitis media; assess

for the swelling behind the ear and pain with minimal movement of thetragus, pinna or the head- Mastoidectomy and myringotomy- IV antibiotics

d. Impacted cerumen blockage within the ear canal as seen in theotoscope and treated by ear irrigation

e. Menieres Disease - over production or decreased reabsorption ofendolymphatic fluid, causing a distortion of the entire inner canalsystem

Three features:a. Tinnitusb. one sided sensorineural hearing lossc. Vertigo occurring in attacks that can last for several days

Cause: unknown; but it often occurs with infections, allergic reaction, andfluid imbalances

Incidence:a. occurs between 20 and 50 yrs oldb. greater in men and in white individualsManifestations:o headacheo increasing tinnituso feeling of fullness in the affected areaManagement:Goal: manage symptomsa. instruct client to make slow head movements to prevent worsening of

the vertigob. diet and lifestyle changes such as salt and fluid decreasec. advise clients to stop smokingd. drug therapy aims to control the vertigo and vomiting and restore

normal balanced.- diuretics mild = triamterene and hydrochlorothiazide (Dyazide,

Maxzide)- anti-vertigo = meclizine (Antivert)- nicotinic acid (vasodilator)- antihistamines (dyphenhydramine HCl)- anti emetics = chlorpromazine HCl, prochlorperazine (Compazine)- anti-anxiety = diazepam, alprazolam (Xanax)

Surgical Management:a. LABYRINTHECTOMY the most radical procedure involves resection of the vestibular nerve or

total removal of the labyrinthb. Transtympanic gentamicin treatment (chemical labyrinthectomy) a

"low dose" variant is extremely effective


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6. Benign paroxysmal positional vertigo (BPPV) - develops when a smallpiece of bone-like calcium breaks free and floats within the tube of theinner ear

Causes, incidence, and risk factors There are no major risk factors. However, the condition may partly run

in families. A prior head injury (even a slight bump to the head) or aninner ear infection called labyrinthitis may make some people morelikely to develop the condition.

Diagnosticsa. Dix-Hallpike maneuverb. ENGc. CT scan / MRId. Hearing teste. Warming and cooling the inner ear with water (caloric stimulation) or

air to test eye movements

Manifestations Feeling of spinning or moving Nausea, vomiting hearing loss loss of balance Vision problems, such as a feeling that things are jumping or movingManagement Epley's maneuver Medications:

a. Antihistaminesb. Anticholinergicsc. Sedative-hypnotics

To prevent symptoms from getting worse during episodes of vertigo,instruct client to avoid positions that trigger it.

Instruct client to notify MD of weakness, slurred speech, or visionproblems are experienced

Complication: dehydration due to frequent vomiting

References:BooksGuyton, A. and Hall, J. (2006). Textbook on Medical Physiology, 11th ed.

PA: Elsevier, Inc.

Porth, C.M. (2010). Essentials of Pathophysiology, 3rded. USA: LippincottWilliams & Wilkins.

Smeltzer, S., et al (2009). Brunner andSuddarths Textbook on Medical-Surgical Nursing, 10th ed. USA: Lippincott Williams & Wilkins.

Williams, L. S. and Hopper P. D. (2007). Understanding Medical-SurgicalNursing, 3rded. PA: F. A. Davis Company

Internet SourcesChildrens Hospital Boston - Harvard Medical School. (2011).Astigmatism,

hyperopia, and myopia. Retrieved December 28, 2011 fromhttp://web1.tch.harvard.edu/az/Site1517/mainpageS1517P0.html

Eye Associates of Wilmington, P.A. (n.d.) Retrieved December 28, 2011from http://www.wilmingtoneye.com/pdfs/Conventional_Glaucoma_Surgery.pdf

National Institutes of Health. (2011). Refractive errors. RetrievedDecember 28, 2011 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002018/

Kasemsuwan, L., et al. (2007). Low Dose Transtympanic GentamicinTreatment forIntractable Menieres Disease: A Prospective Study.Journal of the Medical Association of Thailand (90;2). RetreivedDecember 28, 2011 from http://www.medassocthai.org/journal

LasikEyeSurgery.org. (2010). Lasik eye surgery. Retrieved December 28,2011 from http://www.lasikeyesurgery.org/

National Institutes of Health. (2011). Blindness. Retrieved December 28,2011 from http://www.nlm.nih.gov/medlineplus/ency/article/003040.htm

National Institutes of Health. (2011). Cataracts. Retrieved December 28,2011 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001996/

World Health Organization. (20111). Blindness. Retrieved December 28,2011 from http://www.who.int/topics/blindness/en/
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001996/http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001996/

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