Nursing Management
Visual and Auditory Problems
1. Compare and contrast the types of refractive errors and appropriate corrections.
2. Describe the etiology and collaborative care of extraocular disorders.
3. Explain the pathophysiology, clinical manifestations, and nursing management and collaborative care of the patient with selected intraocular disorders.
4. Discuss the nursing measures that promote the health of the eyes and ears.
5. Elaborate on the general preoperative and postoperative care of patients undergoing surgery of the eye or ear.
6. Summarize the action and uses of drug therapy for treating problems of the eyes and ears.
7. Explain the pathophysiology, clinical manifestations, and nursing and collaborative management of common ear problems.
8. Compare the causes, management, and rehabilitative potential of conductive and sensorineural hearing loss.
9. Explain the use, care, and patient teaching related to assistive devices for eye and ear problems.
10. Describe the common causes and assistive measures for uncorrectable visual impairment and deafness.
11. Describe the measures used to assist the patient in adapting psychologically to decreased vision and hearing.
Reviewed by Sarah Smith, RN, MA, CRNO, COT, Nurse Manager, Department of Ophthalmology, University of Iowa Health Care, Oxford, Iowa; and Helen Stegall, RN, BSN, CORLN, Nurse Manager of Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, Iowa.
eTABLE 22-1
OCULAR MANIFESTATIONS OF SYSTEMIC DISEASES
Systemic Problem | Ocular Manifestations |
Acquired immunodeficiency syndrome | Herpes zoster ophthalmicus, keratitis (bacterial and viral), endophthalmitis (bacterial and fungal), cotton-wool spots and microvasculopathy of the retina, Kaposi sarcoma of eyelids or conjunctiva |
Diabetes mellitus | Fluctuating refractive errors, diabetic retinopathy, macular edema, premature cataract development, increased incidence of glaucoma |
Down syndrome | Myopia, cataracts, nystagmus, strabismus, keratoconus, upward and outward slant of palpebral fissures |
Hypertension | Cotton-wool spots and hemorrhage of the retina, retinal lipid deposits |
Systemic lupus erythematosus | Dry eye, retinal changes, uveitis, scleritis |
Rheumatoid arthritis | Dry eye, keratitis, scleritis |
Infections | |
Botulism | Blurred vision, ptosis, diplopia, fixed and dilated pupil |
Endocarditis | Subconjunctival or retinal petechiae |
Tuberculosis | Conjunctivitis, keratitis, uveitis |
Herpes | Herpes simplex keratitis |
CMV infection | CMV retinitis |
Measles | Conjunctivitis, keratitis, retinopathy |
Histoplasmosis | Chorioretinal lesions, subretinal neovascularization |
Toxoplasmosis | Necrotic retinal lesions, vitreal inflammation |
Lyme disease | Conjunctivitis, keratitis, panophthalmitis, retinal detachment, diplopia |
Syphilis | Conjunctivitis, keratitis, uveitis, retinal detachment, macular edema, glaucoma |
Thyroid Disease | Lid retraction, lid lag, exophthalmos, abnormal eye movement, increased IOP |
Vitamin Deficiencies | |
A | Night blindness, corneal ulceration |
B | Optic neuropathy, corneal changes, retinal hemorrhage, nystagmus |
C | Hemorrhage in anterior chamber, retina, conjunctiva |
D | Exophthalmos |
CMV, Cytomegalovirus; CN, cranial nerve; IOP, intraocular pressure.
eTABLE 22-2
PATIENT & CAREGIVER TEACHING GUIDEAfter Ear Surgery
The chapter describes visual and auditory problems, with an emphasis on their pathophysiology, clinical manifestations, collaborative care, and nursing management. Discussion of assistive devices for visual and hearing impairment is also included.
Visual Problems
Correctable Refractive Errors
The most common visual problem is refractive error. This defect prevents light rays from converging into a single focus on the retina. Defects are a result of irregularities of the corneal curvature, the focusing power of the lens, or the length of the eye. The major symptom is blurred vision. In some cases the patient may also complain of ocular discomfort, eyestrain, or headaches. The principal refractive errors of the eye can be corrected by the use of lenses in the form of eyeglasses or contact lenses, refractive surgery, or surgical implantation of an artificial lens. Contrary to popular belief, failure to correct refractive errors does not worsen the error, nor does it cause any further pathologic conditions after age 6.
Myopia (nearsightedness) is an inability to accommodate for objects at a distance. It causes light rays to be focused in front of the retina. Myopia may occur because of excessive light refraction by the cornea or lens or because of an abnormally long eye. (Refractive errors are depicted in eFig. 22-1 available on the website for this chapter.) Myopia is the most common refractive error, with approximately 25% of Americans having this disorder.
Hyperopia (farsightedness) is an inability to accommodate for near objects. It causes the light rays to focus behind the retina and requires the patient to use accommodation to focus the light rays on the retina for near objects. This type of refractive error occurs when the cornea or lens does not have adequate focusing power or when the eyeball is too short.
Presbyopia is the loss of accommodation associated with age. This condition generally appears at about age 40. As the eye ages, the lens becomes larger, firmer, and less elastic. These changes, which progress with aging, result in an inability to focus on near objects.1
Aphakia is the absence of the lens. Rarely, the lens may be absent congenitally, or it may be removed during cataract surgery. A lens that is traumatically injured is removed and replaced with an intraocular lens (IOL) implant. The lens accounts for approximately 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.
Nonsurgical Corrections
Corrective Glasses.
Myopia, hyperopia, presbyopia, and astigmatism can be modified by using the appropriate corrective lenses. Glasses for presbyopia are often called “reading glasses” because they are usually worn for close work only. The presbyopic correction may also be combined with a correction for another refractive error, such as myopia or astigmatism. In these combined glasses the presbyopic correction is in the lower portion of the spectacle lens. A traditional bifocal or trifocal has visible lines. However, most lenses today that correct vision at various distances do not have visible lines. The prescription varies throughout the lens, allowing distance focusing in the top two thirds and near focus in the bottom one third of the lens.
Contact Lenses.
Contact lenses are another way to correct refractive errors. Contact lenses are made from various plastic and silicone substances that are highly permeable to oxygen and have a high water content. These features allow for increased wearing time with greater comfort. If the oxygen supply to the cornea is decreased, it becomes swollen, visual acuity decreases, and the patient experiences severe discomfort.
Altered or decreased tear formation can make wearing contact lenses difficult. Tear production can be decreased by medications such as antihistamines, decongestants, diuretics, and birth control pills, as well as the hormones produced during pregnancy. Environmental factors such as wind, fans, and dust may also decrease the tear film. Allergic conjunctivitis with itching, tearing, and redness can also affect contact lens wear.
In general, you need to know whether the patient wears contact lenses, the pattern of wear (daily versus extended), and care practices. Shining a light obliquely on the eyeball can help visualize a contact lens. Contact lenses are associated with microbial keratitis, a severe sight-threatening complication. Risk factors for keratitis include poor hand cleaning, poor lens case hygiene, and inadequate lens cleaning.2 Teach the patient the importance of following recommended cleaning practices and reporting redness, sensitivity, vision problems, and pain to the eye care professional. Instruct the patient to remove contact lenses immediately if any of these problems occur.
Surgical Therapy
Surgical procedures are designed to eliminate or reduce the need for eyeglasses or contact lenses and correct refractive errors by changing the focus of the eye. Surgical management for refractive errors includes laser surgery and IOL implantation.
Laser.
Laser-assisted in situ keratomileusis (LASIK) may be considered for patients with low to moderately high amounts of myopia or hyperopia, with or without astigmatism. The procedure first involves using a laser or surgical blade to create a flap in the cornea. The flap is folded back on the middle section, or stroma, of the cornea.3 Pulses from a computer-controlled laser vaporize a part of the stroma. The flap is then repositioned, adhering on its own without sutures in a few minutes.
Implant.
Refractive intraocular lens (refractive IOL) implantation is an option for patients with a high degree of myopia or hyperopia. Like cataract surgery, it involves removal of the patient’s natural lens and implantation of an IOL, which is a small plastic lens to correct a patient’s refractive error. Since this requires entering the eye, the risk of complications is higher. New accommodating IOLs correct both myopia and presbyopia.
Phakic intraocular lenses (phakic IOLs) are sometimes referred to as implantable contact lenses. They are implanted into the eye without removing the eye’s natural lens. They are used for patients with high degrees of myopia or hyperopia. Unlike refractive IOLs, the phakic IOL is placed in front of the eye’s natural lens. Leaving the natural lens in the eye preserves the eye’s ability to focus for reading vision. Artisan is one type of phakic IOL used for moderate to severe myopia.
Uncorrectable Visual Impairment
In the United States, 6.5 million people over age 65 have severe visual impairment, which is defined as the inability to read newsprint even with glasses.4 Of those individuals, 9% have no useful vision, and the remaining 91% are considered partially sighted. The partially sighted individual may still have significant visual abilities.
The patient with either total or functional blindness is considered legally blind. Legal blindness refers to central visual acuity of 20/200 or less in the better eye with correction, or a peripheral visual field of 20 degrees or less. It is estimated that about 1.3 million people in the United States are legally blind. Almost all blindness in the United States is the result of common eye diseases, including cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy. Less than 4% of blindness is the result of injuries.4
Nursing Management Visual Impairment
Nursing Assessment
It is important to assess how long the patient has had a visual impairment, since recent loss of vision has different implications for nursing care. Determine how the patient’s visual impairment affects normal functioning. Question the patient about the level of difficulty involved in doing certain tasks. For example, ask how much difficulty the patient has when reading a newspaper, writing a check, moving from one room to the next, or viewing television. Other questions can help determine the personal meaning that the patient attaches to the visual impairment. Ask how the vision loss has affected specific aspects of the patient’s life, whether the patient has lost a job, or what activities the patient does not engage in because of the visual impairment. The patient may attach many negative meanings to the impairment because of societal views of blindness. For example, the patient may view the impairment as punishment or view himself or herself as useless and burdensome. Determine the patient’s primary coping strategies, the patient’s emotional reactions, and the availability and strength of the patient’s support systems.
Planning
The overall goals are that the patient with recently impaired vision or the patient with poor adjustment to long-standing visual impairment will (1) make a successful adjustment to the impairment, (2) verbalize feelings related to the loss, (3) identify personal strengths and external support systems, and (4) use appropriate coping strategies. If the patient has been functioning at an appropriate or acceptable level, the goal is to maintain the current level of function.
Nursing Implementation
Health Promotion.
Encourage the partially sighted patient with preventable causes of further visual impairment to seek appropriate health care. For example, the patient with vision loss from glaucoma may prevent further visual impairment by complying with prescribed therapies and suggested ophthalmic evaluations.
Acute Intervention.
Provide emotional support and direct care to the patient with recent visual impairment. Allow the patient to express anger and grief, and help the patient identify fears and successful coping strategies. The family is intimately involved in the experiences that follow vision loss. With the patient’s knowledge and permission, include family members in discussions and encourage them to express their concerns.
Many people are uncomfortable around a blind or partially sighted individual because they are not sure what behaviors are appropriate. Being sensitive to the patient’s feelings without being overly worried or smothering the patient’s independence is vital in creating a therapeutic nursing presence. Always communicate in a normal conversational tone and manner with the patient, and address the patient, not the caregiver. Common courtesy dictates introducing oneself and any other people who approach the blind or partially sighted patient and saying good-bye on leaving. Making eye contact with the partially sighted patient accomplishes several objectives. It ensures that you are speaking while facing the patient so the patient has no difficulty hearing. Your head position validates that you are attentive to the patient. In addition, establishing eye contact ensures that you can observe the patient’s facial expressions and reactions.
Assist the patient using a sighted-guide technique. Stand slightly in front and to one side of the patient, and offer an elbow for the patient to hold. Serve as the sighted guide, walking slightly ahead of the patient with the patient holding the back of your arm. As you walk, describe the environment to help orient the patient. For example, “We’re going through an open doorway and approaching two steps down.” Help the patient sit by placing one of his or her hands on the seat of the chair.
Ambulatory and Home Care.
In working with the visually impaired patient, remember that a person classified as legally blind may have some useful vision. Rehabilitation after partial or total loss of vision can foster independence, self-esteem, and productivity. Know what services and devices are available for the partially sighted or blind patient, and make appropriate referrals. For the legally blind patient the primary resource for services is the state agency for rehabilitation of the blind. Legally blind individuals are eligible for federal and state assistance and income tax benefits. A list of agencies that serve the partially sighted or blind patient is available from the American Foundation for the Blind (www.afb.org). Many of these agencies are listed in the resources section at the end of the chapter.
Optical Devices for Vision Enhancement.
A wide range of newer technologies are available to assist people with low vision.5 These devices include desktop video magnification/closed circuit units, electronic hand-held magnifiers, text-to-speech scanners (material read aloud to you), E-readers, and computer tablets (material read aloud, magnification, image zooming, brighter screen, voice recognition). Many of these devices require some training by an assistive technology professional. Encourage patients to practice with the technologic device to ensure they can use it successfully.
Nonoptical Methods for Vision Enhancement.
Approach magnification is a simple way to enhance the patient’s residual vision. Recommend that the patient sit closer to the television or hold books closer to the eyes. Contrast enhancement techniques include watching television in black and white, using a black felt-tip marker, and using contrasting colors (e.g., a red stripe at the edge of steps or curbs). Increased lighting can be provided by halogen lamps, direct sunlight, or gooseneck lamps that can be aimed directly at the reading material or other near objects.6 Large type is often helpful, especially in conjunction with other optical or nonoptical vision enhancements.
Gerontologic Considerations
Visual Impairment
The older adult is at an increased risk for vision loss caused by eye disease. This older person may have other deficits, such as cognitive impairment or limited mobility, that further affect the ability to function in usual ways. Societal devaluation of the elderly may compound the self-esteem or isolation issues associated with the older patient’s visual impairment. Financial resources may meet normal needs but can be inadequate to meet the increased demands of vision services or assistive devices.
The older patient may become confused or disoriented when visually compromised. The combination of decreased vision and confusion increases the risk of falls, which have potentially serious consequences for the older adult. Decreased vision may compromise the older patient’s ability to function, resulting in concerns about maintaining independence and a diminished self-image. Decreased manual dexterity may make the instillation of prescribed eyedrops difficult for some older adults.
Eye Trauma
Although the eyes are well protected by the bony orbit and fat pads, everyday activities can result in ocular trauma. In the United States an estimated 2.5 million eye injuries occur each year. Of those injured, more than 10% will lose useful vision in the affected eye. Table 22-1 outlines emergency management of the patient with an eye injury. The most common ocular injuries in the United States occur in the home due to gardening, power tool use, and home repair work.7 Sport and work-related injuries are additional causes of eye trauma.
TABLE 22-1
EMERGENCY MANAGEMENTEye Injury
Trauma is often a preventable cause of visual impairment. Many eye injuries could be prevented by wearing protective eyewear. Your role in individual and community education is extremely important in reducing the incidence of ocular trauma.
Extraocular Disorders
Inflammation and Infection
One of the most common conditions encountered by the ophthalmologist is inflammation or infection of the external eye. Many external irritants or microorganisms can affect the eye, conjunctiva, and avascular cornea. It is your responsibility to teach the patient appropriate interventions related to the specific disorder.
An external hordeolum (commonly called a sty) is an infection of the sebaceous glands in the lid margin (Fig. 22-1). The most common bacterial infective agent is Staphylococcus aureus. A red, swollen, circumscribed, and acutely tender area develops rapidly. Instruct the patient to apply warm, moist compresses at least four times a day until it improves. This may be the only treatment necessary. If it tends to recur, teach the patient to perform lid scrubs daily. In addition, appropriate antibiotic ointments or drops may be indicated.
A chalazion is a chronic inflammatory granuloma of the meibomian (sebaceous) glands in the lid. It may evolve from a hordeolum or occur in response to the material released into the lid when a blocked gland ruptures. The chalazion usually appears on the upper lid as a swollen, tender, reddened area that may be painful. Initial treatment is similar to that for a hordeolum. If warm, moist compresses are ineffective in promoting spontaneous drainage, the ophthalmologist may surgically remove the lesion (this is normally an office procedure) or inject the lesion with corticosteroids.
Blepharitis is a common chronic bilateral inflammation of the lid margins.8 The lids are red rimmed with many scales or crusts on the lid margins and lashes. The patient may primarily complain of itching but may also experience burning, irritation, and photophobia. Conjunctivitis may occur simultaneously.
Conjunctivitis
Conjunctivitis is an infection or inflammation of the conjunctiva. These infections may be caused by bacteria or viruses. Conjunctival inflammation may result from exposure to allergens or chemical irritants. The tarsal conjunctiva (lining the interior surface of the lids) may become inflamed as a result of a chronic foreign body in the eye, such as a contact lens. Careful hand washing and use of individual or disposable towels help prevent spreading the condition.
Bacterial Infections.
Acute bacterial conjunctivitis (pinkeye) is a common infection. Although it occurs in every age-group, epidemics are common among children because of their poor hygienic habits. S. aureus is the most common cause. The patient with bacterial conjunctivitis may complain of discomfort, pruritus, redness, and a mucopurulent drainage.9 Although this typically occurs initially in one eye, it generally spreads to the unaffected eye. It is usually self-limiting, but treatment with antibiotic drops (e.g., besifloxacin [Besivance]) shortens the course of the disorder.
Viral Infections.
Conjunctival infections may be caused by many different viruses. The patient with viral conjunctivitis may complain of tearing, foreign body sensation, redness, and mild photophobia. This condition is usually mild and self-limiting. However, it can be severe, with increased discomfort and subconjunctival hemorrhaging. Adenovirus conjunctivitis may be contracted in contaminated swimming pools and through direct contact with an infected patient. Treatment is usually palliative. If the patient is severely symptomatic, topical corticosteroids can provide temporary relief but have no effect on the final outcome. Antiviral drops are ineffective and therefore not indicated.
Chlamydial Infections.
Trachoma is a chronic conjunctivitis caused by Chlamydia trachomatis (serotypes A through C). It is a major cause of blindness worldwide. An estimated 84 million people have active disease in need of treatment if blindness is to be prevented, with 8 million people already living with irreversible vision loss.10
Manifestations of both trachoma and AIC are mucopurulent ocular discharge, irritation, redness, and lid swelling. For unknown reasons, AIC does not carry the long-term consequences of trachoma. AIC also differs from trachoma in that it is common in economically developed countries, whereas trachoma is most commonly seen in underdeveloped countries. Antibiotic therapy is usually effective for trachoma and AIC.
Although antibiotic treatment may be successful, patients with AIC have a high risk of concurrent chlamydial genital infection, as well as other sexually transmitted infections. In your teaching plan for these patients, include the sexual implications of AIC.
Allergic Conjunctivitis.
Conjunctivitis caused by exposure to an allergen can be mild and transitory, or it can be severe enough to cause significant swelling, sometimes ballooning the conjunctiva beyond the eyelids. The defining symptom of allergic conjunctivitis is itching. The patient may also complain of burning, redness, and tearing. In addition to pollens, the patient may develop allergic conjunctivitis in response to animal dander, ocular solutions, and medications. Instruct the patient to avoid the allergen if it is known. Artificial tears can be effective in diluting the allergen and washing it from the eye. Effective topical medications include antihistamines and corticosteroids.
Keratitis
Keratitis is an inflammation or infection of the cornea that can be caused by a variety of microorganisms or by other factors. The condition may involve the conjunctiva and/or the cornea. When it involves both, the disorder is termed keratoconjunctivitis.
Bacterial Infections.
The cornea can become infected by a variety of bacteria. Topical antibiotics are generally effective, but eradicating the infection may require subconjunctival antibiotic injection or, in severe cases, IV antibiotics. Risk factors include mechanical or chemical corneal epithelial damage, contact lens wear, nutritional deficiencies, immunosuppressed states, and contaminated products (e.g., lens care solutions and cases, topical medications, cosmetics).
Viral Infections.
Herpes simplex virus (HSV) keratitis is the most frequently occurring infectious cause of corneal blindness in the Western hemisphere. It is a growing problem, especially with immunosuppressed patients. The corneal ulcer has a characteristic dendritic (tree-branching) appearance. Pain and photophobia are common. Up to 40% of patients with herpetic keratitis heal spontaneously.
Antiviral treatments include trifluridine drops (Viroptic), oral acyclovir (Zovirax), and topical vidarabine (Vira-A) ointment.11 Therapy may also involve corneal debridement. Topical corticosteroids are usually contraindicated because they contribute to a longer course and possible deeper ulceration of the cornea.
Epidemic keratoconjunctivitis (EKC) is the most serious ocular adenoviral disease. EKC is spread by direct contact, including sexual activity. In the medical setting, contaminated hands and instruments can be the source of spread. The patient may complain of tearing, redness, photophobia, and foreign body sensation. In most patients the disease involves only one eye. Treatment is primarily palliative and includes ice packs and dark glasses. In severe cases therapy can include mild topical corticosteroids to temporarily relieve symptoms and topical antibiotic ointment. Teach the patient and the caregiver the importance of good hygiene practices to avoid spreading the disease.
Other Causes of Keratitis.
Keratitis may also be caused by fungi (most commonly Aspergillus, Candida, and Fusarium species), especially in the case of ocular trauma in an outdoor setting where fungi are prevalent in the soil and moist organic matter.
Acanthamoeba keratitis is caused by a parasite that is associated with contact lens wear, probably as a result of contaminated lens care solutions or cases. Homemade saline solution is particularly susceptible to Acanthamoeba contamination. Instruct the patient who wears contact lenses about good lens care practices. Medical treatment of Acanthamoeba keratitis is difficult, since the organism is resistant to most drugs. Only one antifungal eyedrop (natamycin [Natacyn]) is approved by the U.S. Food and Drug Administration (FDA). If antimicrobial therapy fails, the patient may require a corneal transplant.
Exposure keratitis occurs when the patient cannot adequately close the eyelids. The patient with exophthalmos (protruding eyeball) from thyroid eye disease or masses posterior to the globe is susceptible to exposure keratitis.
Corneal Ulcer.
Tissue loss caused by infection of the cornea produces a corneal ulcer (infectious keratitis) (Fig. 22-2). The infection can be due to bacteria, viruses, or fungi. Corneal ulcers are often painful, and patients may feel as if there is a foreign body in their eye. Other symptoms can include tearing, purulent or watery discharge, redness, and photophobia. Treatment is generally aggressive to avoid permanent loss of vision. Antibiotic, antiviral, or antifungal eyedrops may be prescribed as frequently as every hour night and day for the first 24 hours. An untreated corneal ulcer can result in corneal scarring and perforation (hole in the cornea). A corneal transplant may be indicated.
Nursing Management Inflammation and Infection
Assess ocular changes, such as edema, redness, decreased visual acuity, feelings that a foreign body is present, or discomfort. Document the findings in the patient’s record. Also consider the psychosocial aspects of the patient’s condition, especially when vision is impaired.
Careful asepsis and frequent, thorough hand washing are essential to prevent spreading organisms from one eye to the other, to other patients, to family members, and to health care professionals. Teach the patient and the family about avoiding sources of ocular irritation or infection and responding appropriately if an ocular problem occurs. Inform the patient about appropriate use and care of lenses and lens care products. The patient with infective disorders that may have a sexual mode of transmission needs specific information about those disorders.
Apply warm or cool compresses if indicated for the patient’s condition. Darkening the room and providing an appropriate analgesic are other comfort measures. If the patient’s visual acuity is decreased, modify the patient’s environment or activities for safety.
The patient may require eyedrops as frequently as every hour. If the patient receives two or more different drops, stagger the eyedrops to promote maximum absorption. For example, if two different eyedrops are ordered hourly, administer one drop on the hour and one drop on the half hour (unless otherwise prescribed). The patient who needs frequent eyedrop administration may experience sleep deprivation.
The patient’s primary need in the home environment is for information about required care and how to accomplish that care. Also instruct the patient and the caregiver about the proper techniques for medication administration. If the patient’s vision is compromised, suggest alternative ways to accomplish necessary daily activities and self-care. Inform the patient who wears contact lenses and develops infections to discard all opened or used lens care products and cosmetics to decrease the risk of reinfection from contaminated products (a common problem and a probable source of infection for many patients).
Dry Eye Disorders
Keratoconjunctivitis sicca (dry eyes) is a common complaint, particularly of older adults and individuals with certain systemic diseases such as scleroderma and systemic lupus erythematosus. Patients with dry eyes complain of irritation or “sand in my eye” and that the sensation typically worsens through the day. This condition is caused by a decrease in the quality or quantity of the tear film, and treatment is directed at the underlying cause. With decreased tear secretion, the patient may use artificial tears or ointments. In severe cases, closure of the lacrimal puncta may be necessary. Patients with dry eyes associated with dry mouth may have Sjögren’s syndrome (see Chapter 65).
Strabismus
Strabismus is a condition in which the patient cannot consistently focus two eyes simultaneously on the same object. One eye may deviate in (esotropia), out (exotropia), up (hypertropia), or down (hypotropia) (see eFig. 22-2 available on the website for this chapter). Strabismus in the adult may be caused by thyroid disease, neuromuscular problems of the eye muscles, retinal detachment repair, or cerebral lesions. In the adult the primary complaint with strabismus is double vision.
Corneal Disorders
Corneal Scars and Opacities
The cornea is an optically transparent tissue that allows light rays to enter the eye and focus on the retina, thus producing a visual image. Any wound causes the cornea to become abnormally hydrated and decreases the normal transparency. The treatment for corneal scars or opacities is penetrating keratoplasty (corneal transplant). The ophthalmic surgeon removes the full thickness of the patient’s cornea and replaces it with a donor cornea that is sutured into place (Fig. 22-3). Vision may not be restored for up to 12 months. Newer procedures in which only the damaged cornea epithelial layer is replaced are Descemet’s stripping endothelial keratoplasty (DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK).12 Patients report faster visual recovery with less astigmatism and changes in their glass lens prescription with these surgeries.
Approximately 40,000 corneal transplants are performed in the United States each year. The surgery is one of the fastest and safest of all tissue or organ transplant surgeries. The time between the donor’s death and the removal of the tissue should be as short as possible. The eye banks test donors for human immunodeficiency virus (HIV) and hepatitis B and C. The tissue is preserved in a special nutritive solution. Improved methods of tissue procurement and preservation, postoperative topical corticosteroids, and careful follow-up have decreased graft rejection. Matching the blood type of the donor and the recipient may also improve the success rate.
Keratoconus
Keratoconus is a noninflammatory, usually bilateral disease that has a familial tendency. Keratoconus usually appears during adolescence and slowly progresses between ages 20 and 60 years. The anterior cornea thins and protrudes forward, taking on a cone shape. The only symptom is blurred vision. The astigmatism may be corrected with glasses or rigid contact lenses.
Intacs inserts are two clear plastic lenses surgically inserted on the cornea perimeter to reduce astigmatism and myopia. Intacs are generally used to delay the need for a corneal transplant when contact lenses or glasses no longer help a patient achieve adequate vision.
The cornea can perforate as central corneal thinning progresses. In advanced cases a penetrating keratoplasty is indicated before perforation.
Intraocular Disorders
Cataract
A cataract is an opacity within the lens. The patient may have a cataract in one or both eyes. If cataracts are present in both eyes, one may affect the patient’s vision more than the other. Almost 22 million Americans ages 40 years and older have cataracts, and by age 80 more than 50% have cataracts. Direct medical costs for cataract treatment are estimated at $6.8 billion annually. Cataract removal is the most common surgical procedure in the United States.13
Etiology and Pathophysiology
Although most cataracts are age related (senile cataracts), they can be associated with other factors. These include blunt or penetrating trauma, congenital factors such as maternal rubella, radiation or ultraviolet (UV) light exposure, certain drugs such as systemic corticosteroids or long-term topical corticosteroids, and ocular inflammation. The patient with diabetes mellitus tends to develop cataracts at a younger age.
Cataract development is mediated by a number of factors. In senile cataract formation it appears that altered metabolic processes within the lens cause an accumulation of water and alterations in the lens fiber structure. These changes affect lens transparency, causing vision changes.
Clinical Manifestations and Diagnostic Studies
The patient with cataracts may complain of a decrease in vision, abnormal color perception, and glare. Glare is due to light scatter caused by the lens opacities, and it may be significantly worse at night when the pupil dilates. The visual decline is gradual, but the rate of cataract development varies from patient to patient. Diagnosis is based on decreased visual acuity or other complaints of visual dysfunction. The opacity is directly observable by ophthalmoscopic or slit lamp microscopic examination. As noted earlier, a totally opaque lens creates the appearance of a white pupil. Table 22-2 lists other diagnostic studies that may be helpful in evaluation of a cataract.
TABLE 22-2
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