Chapter 51. Eye and Vision Disorders. Elsevier items and derived items 2007 by Saunders, an imprint of Elsevier, Inc.

Transcription

1 Chapter 51 Eye and Vision Disorders 1

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5 Visual Pathway Light enters eye, passes through transparent cornea, aqueous humor, lens, and vitreous humor These structures are called refractive media Refract (bend) horizontal and vertical light rays so that the light rays focus on the retina On retina, light rays are reversed and upside down Images carried as impulses through the optic nerve At optic chiasm, fibers from the left field from each eye join to form the left optic tract Fibers from right field of eye join to form right optic tract Images transmitted to the brain by way of the optic tracts 5

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7 Age-Related Changes in the Eye Skin around the eye becomes wrinkled and loose Eyelids usually have some excess tissue; not important unless it interferes with vision The amount of fat around the eye decreases, permitting the eyeball to sink deeper into the orbit Tear secretion diminishes; cornea less sensitive Grayish ring may be around the outer margin of the iris Pupil smaller and responds more slowly to light Presbyopia: ability to focus is impaired 7

8 Health History History of present illness Record changes in vision If pain, inquire about location and nature Sensitivity to light (photophobia) Discharge from the eyes Complaints that the eyes feel dry and irritated Past medical history Diabetes, neurologic disorders, thyroid disease, hypertension 8

9 Health History Family history Any eye diseases as well as a history of arteriosclerosis, diabetes, and thyroid disease Functional assessment Patient s occupation, roles, usual activities 9

10 Physical Examination Inspect the external eye, assess response of the pupil to light, and evaluate gross visual acuity If abnormalities suspected, inform physician or advise patient to seek medical evaluation Acuity commonly tested with Snellen chart 10

11 Diagnostic Tests and Procedures Ophthalmoscopic examination Refractometry Visual fields Tonometry Fluorescein angiography Corneal staining Imaging procedures CT, ultrasonography, radioisotope scanning, or MRI 11

12 Therapeutic Measures Eye irrigation Topical medications Miotics Mydriatics Anesthetics Cycloplegics Antibiotics Anti-inflammatory drugs Eye surgery Surgical incisions, lasers, and cryotherapy 12

13 Preoperative Nursing Care Assessment Patient s emotional state, ability to perform selfcare, and knowledge of surgical routines and outcomes Be sure the patient understands the preoperative routine Interventions Anxiety Self-Care Deficit 13

14 Postoperative Nursing Care Assessment Vital signs and level of consciousness Inspect dressing for bleeding or drainage Patient comfort, including pain and nausea If vision impaired, inspect environment for safety hazards Before discharge, determine patient s understanding of and ability to administer prescribed medications by having the patient demonstrate self-medication 14

15 Postoperative Nursing Care Interventions Risk for Injury Disturbed Sensory Perception Acute Pain Anxiety Ineffective Therapeutic Regimen Management 15

16 Protection of the Eyes and Vision Patient teaching Adults younger than 40 years of age should have their eyes examined every 3 to 5 years After the age of 40, examinations every 2 years and should include testing for glaucoma When there are symptoms of eye problems, patients should seek medical advice 16

17 Protection of the Eyes and Vision Prevention of injuries Teach young children the danger of throwing or poking objects at the faces of playmates Assess toys for safety Adult activities that produce sparks or cause fragments to be dispersed also cause injuries Advise protective eyewear for such potentially dangerous activities 17

18 Protection of the Eyes and Vision Basic eye care Gently cleanse the eyelids each time the face is washed; use a clean cloth without soap Wash eye from the inner canthus (near the nose) toward the outer canthus 18

19 Effect of Visual Impairment Mild losses may require only some adaptations Serious losses affect independence, mobility, employment, and interpersonal relationships People grieve for the lost function just as they might grieve after the death of a loved one Factors that affect a person s response to this loss include personality, usual coping style, effect of vision loss on the person s life, and the circumstances of the loss 19

20 Care of the Visually Impaired Patient Be aware of visually impaired person s thoughts and feelings about handicaps Assume that people with visual impairments can be independent and productive The person needs help with some tasks but should be treated as an adult The extent of vision loss determines the types of assistance needed 20

21 Care of the Visually Impaired Patient Interventions Disturbed Sensory Perception Ineffective Coping Self-Care Deficit Ineffective Therapeutic Regimen Management 21

22 Blepharitis Inflammation of hair follicles along eyelid margin Caused by bacteria, most often by staphylococci Symptoms include itching, burning, and photophobia; scales or crusts on the lid margins Physician may prescribe an antibiotic ointment Be certain that any medication applied to the eye is an ophthalmic preparation Eyelids can be gently cleansed with baby shampoo solution 22

23 Hordeolum Commonly called a stye Common acute staphylococcal infection of the eyelid margin that originates in a lash follicle Affected area of lid is red, swollen, and tender Apply warm, moist compresses several times a day Repeated infections may be related to staphylococcal infections at some other location on the body Physician may treat with ophthalmic antibiotics 23

24 Chalazion Inflammation of the glands in the eyelids Swelling prevents fluid from leaving the glands, causing tenderness Warm compresses may bring some relief Physician may order antibiotics if infection Surgical removal of the gland necessary if condition persists 24

25 Conjunctivitis Inflammation of the conjunctiva caused by microorganisms, allergy, or chemical irritants Bacterial conjunctivitis commonly called pinkeye Red conjunctiva, mild irritation, drainage Warm/cool compresses, topical vasoconstrictors Infected people should practice good hand washing and should avoid sharing washcloths 25

26 Conjunctivitis Viral conjunctivitis caused by herpes simplex virus type 1, herpes zoster virus, or adenoviruses Characterized by redness and drainage Round, raised white or gray areas on the conjunctiva Infections caused by herpes simplex virus type 1 are treated with ointments or other topical medications 26

27 Keratitis Inflammation or infection, or both, of the cornea From bacteria, viruses, fungi; chemical or mechanical injuries cause inflammation that may be followed by infection No noticeable drainage, but considerable pain Topical antibiotics and topical corticosteroids Systemic antibiotics after culture and sensitivity Sometimes physician injects antibiotics directly into the conjunctiva 27

28 Entropion The lower lid turns inward Eyelashes rub against the eye, causing pain and possibly scratching the cornea Surgical correction usually recommended 28

29 Ectropion The lower lid droops and turns outward The eye does not close completely, causing it to become dry and irritated The dry cornea is easily injured Requires surgical correction 29

30 Foreign Body Blinking/tearing wash small irritants from eye If foreign body remains, evert the upper and lower lids If object is clearly visible and does not appear to be embedded, you may attempt to remove it Use sterile cotton swab to touch object gently If object not embedded, it usually clings to swab and can be removed If object is embedded, it should be removed only by a physician 30

31 Corneal Opacity Inflammation and infection When cornea injured by infection or trauma, scar tissue may form If scar tissue prevents light from entering the eye, varying degrees of vision impairment occur Only treatment is keratoplasty (removal of the scarred cornea and replacement with a healthy cornea) During keratoplasty, damaged cornea removed first An identically sized graft then taken from the donor eye and secured to the recipient s eye with very fine suture 31

32 Care of the Patient Having Keratoplasty After surgery, the keratoplasty patient has an eye pad and a metal shield over the operative eye Corticosteroid eye drops may be ordered to reduce inflammation 32

33 Care of the Patient Having Keratoplasty Assessment Inspect dressing for drainage and ask if patient has pain or nausea After dressing is removed, inspect for corneal opacity Also evaluate the patient s visual acuity Interventions Risk for Injury Pain Impaired Sensory Perception Ineffective Therapeutic Regimen Management 33

34 Myopia The medical term for nearsightedness The lens is situated too far from the retina Light rays come together to focus in front of the retina People with myopia have difficulty seeing distant images clearly New glasses needed approximately every 2 years 34

35 Hyperopia Commonly known as farsightedness The lens is too close to the retina Light rays come together behind the retina The hyperopic person sees clearly in the distance but has difficulty focusing on close objects Convex corrective lenses needed 35

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37 Astigmatism Irregularities in the cornea or lens If condition is mild, the natural lens can correct for the abnormality If severe, vision is distorted, and corrective lenses are needed 37

38 Presbyopia Poor accommodation due to loss of elasticity of the ciliary muscles Accommodation: adjustment of the lens for near and distant vision Contraction or relaxation of the ciliary muscles, which causes the lens to change shape It most often develops after age 40 years Corrective lenses are needed 38

39 Medical Treatment Corrective lenses for errors of refraction Eyeglasses Contact lenses Surgical treatment Photorefractive keratectomy (PRK) Laser in situ keratomileusis (LASIK) Nursing care Encourage periodic examinations and know if the patient uses corrective lenses 39

40 Cataract Lens opaque (cloudy); no longer transparent Causes: congenital, traumatic, degenerative Pathophysiology Injuries cause opacity rapidly, whereas age-related opacity progresses slowly Signs and symptoms: cloudy vision, seeing spots or ghost images, and floaters Medical treatment Cataract extraction 40

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42 Cataract Complications Leakage of vitreous humor, hemorrhage into the eye, and opening of the incision Lens replacement Cataract eyeglasses Contact lenses Intraocular lenses 42

43 Care of the Patient with Cataracts Preoperative care Drops used before cataract surgery are mydriatics, cycloplegics, antibiotics, and nonsteroidal antiinflammatory agents 43

44 Care of the Patient with Cataracts Postoperative care Assessment Pain and nausea Patient is likely to wear a patch and shield over operative eye Note any drainage Also note level of consciousness and orientation Interventions Risk for Injury Impaired Sensory Perception 44

45 Glaucoma Pathophysiology Intraocular pressure is above normal Caused by interference with outflow of aqueous humor Although glaucoma may follow trauma, exact cause is often unknown Peripheral vision is lost first Field of vision gradually narrows until tunnel vision Complete blindness eventually occurs 45

46 Types of Glaucoma Open-angle glaucoma Prevents the normal passage of aqueous humor through the trabecular meshwork Usually there are no signs and symptoms at first Tired eyes, blurred vision, and halos around lights Need for frequent changes in eyeglass prescriptions Treated first with drug therapy Beta-adrenergic blockers, adrenergics, cholinergics, carbonic anhydrase inhibitors, and hyperosmotic agents Surgical procedures: trabeculoplasty, trabeculectomy, and cyclocryotherapy 46

47 Glaucoma Angle-closure glaucoma Flow of aqueous humor through the pupil is blocked Pressure forces iris forward; blocks trabecular meshwork Rapid rise in intraocular pressure; if not lowered promptly, permanent blindness can result Signs and symptoms: sudden, acute pain; blurred vision, halos around lights, nausea and vomiting, and headache on the affected side Drugs for treatment: miotics and oral or intravenous carbonic anhydrase inhibitors After pressure lowered, iridotomy or iridectomy usually recommended to prevent recurrence 47

48 Glaucoma Assessment Collect data about patient knowledge of the disease and treatment and patient ability to carry out selfcare Interventions Risk for Injury Fear and Ineffective Therapeutic Regimen Management Pain 48

49 Retinal Detachment Pathophysiology Separation of sensory layer from pigmented layer Begins when a tear in the retina allows fluid to collect between the sensory and the pigmented layers The fluid causes the two layers to separate Separation deprives sensory layers of nutrients and oxygen that normally are supplied by the blood vessels in the choroid Leads to damage to the nerve tissue in the sensory layer and resultant partial or complete loss of vision Retinal tears may occur spontaneously or as a result of trauma 49

50 Retinal Detachment Signs and symptoms Depend on location and extent of detachment Patients report seeing light flashes or floaters Vision may be cloudy If area of detachment is large, vision may be lost completely Some patients say it seems as if a curtain has come down or across the line of vision 50

51 Retinal Detachment Medical and surgical treatment Laser photocoagulation Cryotherapy Scleral buckling 51

52 Retinal Detachment Nursing care Before corrective measures, the patient usually is placed on strict bed rest with the head elevated Postoperative care essentially the same as for other patients undergoing eye surgery Positioning orders may be specific for these patients Surgeon prescribes activity limitations; length of hospitalization depends on location and severity of the tear, the type of repair, and the surgeon s routines 52

53 Senile Macular Degeneration Changes in the eye cause the macula to degenerate Both eyes usually affected Two types Dry (strophic) Abnormal blood vessels develop in or near the macula resulting in loss of vision in a specific area Wet (exudative) Central vision gets gradually worse Special telescopic lenses may be helpful Laser treatments may offer hope to some patients Nurse needs to help the patient and family members learn to cope with declining vision 53

54 Enucleation Removal of the eye From injury, infection, sympathetic ophthalmia, and some glaucomas and malignancies Postoperative observe for excessive bleeding or increasing pain Report any temperature elevation After pressure dressing removed, physician may order wound care and topical medications Approximately 1 month after the enucleation, a prosthesis can be fitted by an optician 54