Chap 19 Disorders of Visual Function
The nurse is admitting a client documented to have papilledema. The nurse recognizes that papilledema is most commonly caused by which condition?
Intracranial pressure Explanation: The central retinal artery enters the eye through the optic papilla in the center of the optic nerve. An accompanying vein exits the eye along the same path. The entrance and exit of the central retinal artery and vein through the tough scleral tissue at the optic papilla can be compromised by any condition causing persistent increased intracranial pressure. The most common of these conditions are cerebral tumors, subdural hematomas, hydrocephalus, and malignant hypertension. Usually, the thin-walled, low-pressure veins are the first to collapse, with the consequent backup and slowing of arterial blood flow. Under these conditions, capillary permeability increases and leakage of fluid results in edema of the optic papilla, called papilledema.
A client presents to the clinic complaining, "I have something in my eye." When questioned, the client admits to a scratching and burning sensation and light sensitivity. The health care provider suspects the client has developed:
Conjunctivitis Explanation: Conjunctivitis causes bilateral tearing, itching, burning, foreign body sensation, and morning eyelash crusting and eye redness. The primary symptom of retinal detachment is painless changes in vision. Commonly, flashing lights or sparks, followed by small floaters or spots in the field of vision, are early symptoms. Attacks of glaucoma (increased intraocular pressure) are manifested by ocular pain, excruciating headache, blurred or iridescent vision, and corneal edema with hazy cornea, dilated (mydriasis), and fixed pupil; with repeated or prolonged attacks, the eye becomes reddened. With corneal edema, the cornea appears dull, uneven, and hazy; visual acuity decreases; and iridescent vision (i.e., rainbows around lights) occurs.
A client has blindness in the right eye. The nurse documenting in the electronic medical record would use which term for blindness in one eye?
Anopia Explanation: Blindness in one eye is called anopia. If half of the visual field for one eye is lost, the defect is called hemianopia; if a quarter of the field is lost, it is called quadrantanopia. Loss of the temporal or peripheral visual fields on both sides results in a narrow binocular field, commonly called tunnel vision.
The students are reviewing the anatomy of the eye and where the eye structures are located. Where is the anterior chamber located?
Anterior segment of the globe Explanation: The anterior chamber is in the anterior segment of the globe, not the posterior segment of the globe, choroid, or retina.
A 64-year-old client comes to the clinic for a routine checkup and, while talking to the nurse, discusses some recent vision problems. Upon examination the nurse notices that the client's lenses are yellow. The client further states there have been problems with color discrimination as well as distance vision. What should the nurse suspect as the diagnosis for this client?
Cataracts Explanation: A cataract is a lens opacity that interferes with the transmission of light to the retina. Aging is the most common cause of cataracts. With further progression, there can be loss of color discrimination and also loss of vision, typically greater for distance that for near vision. This condition has nothing to do with the retina. Hyperopia is another term for farsightedness. Presbyopia refers to a decrease in accommodation that occurs because of aging.
Where in the eye does the major refraction of light begin?
Convex corneal surface Explanation: In the eye, the major refraction of light begins at the convex corneal surface. Further refraction occurs as light moves from the posterior corneal surface to the aqueous humor, from the aqueous humor to the anterior lens surface, from the anterior lens surface to the posterior lens surface, and from the posterior lens surface to the vitreous humor.
The nurse is conducting a vision assessment on a 2-year-old child. The nurse should assess for which visual ability in this child?
Fixation on an object Explanation: The best vision assessment for infants and children under 3 years of age is accomplished by determining whether each eye can fixate on an object, maintain fixation, and follow the object. Recognizing letters and shapes and numbers is not appropriate for a 2-year-old.
A clent has damage to the epithelial layer of the cornea. Which are clinical manifestations that can occur with damage to the epithelial layer of the cornea? Select all that apply.
Foreign body sensation Burning of the eyes Reflex lacrimation Explanation: Epithelial damage causes discomfort that ranges from a foreign body sensation and burning of the eyes to severe, incapacitating pain. Reflex lacrimation is common.
The nursing student who is studying pathophysiology correctly identifies the condition that characteristically has an increase in the aqueous humor that fills the anterior and posterior chambers of the eye. What is this disease called?
Glaucoma Explanation: Glaucoma is a chronic degenerative optic neuropathy characterized by optic disk cupping and visual field loss. It is usually associated with an elevation in intraocular pressure. Amblyopia is lazy eye. Retinopathy is a disorder of the retinal vessels that interrupts blood flow to the visual receptors leading to visual impairment. A cataracts is a lens opacity that interferes with the transmission light to the retina.
As part of the community health department, a nurse is educating a group of diabetic clients about prevention of blindness. Which topics should be covered during this class? Select all that apply.
Importance of yearly eye exams Tight control of blood glucose levels Keep BP below 130/85 (American Heart Association Guidelines) Explanation: Current guidelines recommend that persons with diabetes have yearly eye examinations. Preventing diabetic retinopathy from developing or progressing is considered the best approach to preserving vision. Growing evidence suggests that careful control of blood glucose levels in persons with diabetes mellitus may retard the onset and progression of retinopathy. There also is a need for intensive management of hypertension and hyperlipidemia, both of which have been shown to increase the risk of diabetic retinopathy in persons with diabetes.
During an eye assessment the nurse notes inflammation of the client's cornea. The nurse should document this as which condition?
Keratitis Explanation: Keratitis, or inflammation of the cornea, can be caused by infections, hypersensitivity reactions, ischemia, trauma, defects in tearing, or trauma.
A client has been diagnosed with hemianopia. The client asks the nurse what this is describing concerning the eye?
Loss of half of the visual field in one eye Explanation: Blindness in one eye is called anopia. If half of the visual field for one eye is lost, the defect is called hemianopia; if a quarter of the field is lost, it is called quadrantanopia. Loss of the temporal or peripheral visual fields on both sides results in a narrow binocular field, commonly called tunnel vision.
A client has glaucoma. The nurse is taking a health history and knows that the most common form of glaucoma is which type?
Open angle Explanation: Open-angle glaucoma is the most common form of glaucoma, and is usually asymptomatic and chronic, causing progressive damage to the optic nerve and visual field loss unless it is appropriately treated. Angle-closure glaucoma usually occurs as the result of an inherited anatomic defect that causes a shallow anterior chamber. There are several types of childhood glaucoma, including congenital glaucoma that is present at birth and infantile glaucoma that develops during the first 2 to 3 years of life.
An older adult client comes to the clinic complaining of seeing flashing lights and small spots. The client tells the nurse that this has been going on for over 24 hours but now it is as if there is a dark curtain whenever the client opens the eyes. The client asks the nurse if this means that blindness is imminent. What diagnosis should the nurse suspect?
Retinal detachment Explanation: The primary symptom of retinal detachment consists of painless changes in vision. Commonly, flashing lights or sparks followed by small floaters or spots in the field of vision occur. As the detachment progresses the person perceives a shadow or dark curtain across the visual field.
A client diagnosed with ulcerative keratitis of the cornea asks the nurse what could have caused this type of keratitis. What are common causes of ulcerative keratitis? Select all that apply.
S. aureus, S. pneumoniae, C. trachomatis Exposure trauma Extended-wear contact lenses Explanation: Ulcerative keratitis is an inflammatory process in which parts of the epithelium, stroma, or both are destroyed. Causes of ulcerative keratitis include infectious agents such as those causing conjunctivitis (e.g., S. aureus, S. pneumoniae, C. trachomatis), exposure trauma, and use of extended-wear contact lenses (i.e., Pseudomonas keratitis and Acanthamoeba keratitis).
Binocular vision depends on the coordination of how many pairs of extraocular nerves that provide for the conjugate eye movements?
Three Explanation: Binocular vision depends on the coordination of three pairs of extraocular nerves that provide for the conjugate eye movements, with optical axes of the two eyes maintained parallel with one another as the eyes rotate in their sockets.
The nurse is teaching a client about the treatment of open-angle glaucoma. The most appropriate information for the nurse to give the client would be:
administration of topical beta-adrenergic antagonists to lower the pressure. Explanation: The elevation in intraocular pressure in persons with open-angle glaucoma is usually treated pharmacologically or, in cases where pharmacologic treatment fails, by increasing aqueous outflow through a surgically created pathway. Medication is generally administered topically.
A client is distraught because she has suddenly lost vision in the right half of both of her eyes. The care team's subsequent diagnostic testing will address the likelihood of:
an optic nerve lesion. Explanation: This client is reporting complete right homonymous hemianopia, which is the result of an optic nerve lesion. Multiple sclerosis, diabetes, and macular degeneration produce more gradual and insidious vision changes that do not normally result in hemianopia.
A client tells the health care provider he has noticed a recent change in his vision: he can bring distant images into focus, but near images become blurred. The client has most likely developed:
hyperopia. Explanation: Hyperopia or farsightedness occurs when the accommodative changes of the lens can bring distant images into focus, but near images become blurred. Persons with myopia or nearsightedness can see close objects without a problem because accommodative changes in their lens bring near objects into focus, but distant objects are blurred. Astigmatism is a refractive defect of the corneal surface.
The ophthalmologist is performing a client's annual eye exam and notes an increase in intraocular pressure. The condition most likely is the result of:
imbalance between aqueous production and outflow. Explanation: Increases in intraocular pressure occur when there is an imbalance between aqueous production and outflow. A cell breakdown in the macula lutea results in macular degeneration. Cataracts may cause blurring of vision but do not alter pressure.
The nurse documents the presence of nystagmus when assessing a client. This can be interpreted as:
involuntary eye movements that preserve eye fixation on stable objects in the visual field. Explanation: Nystagmus refers to the involuntary eye movements that preserve eye fixation on stable objects in the visual field during angular and rotational movements of the head. As the body rotates, the vestibuloocular reflexes cause a slow compensatory drifting of eye movement in the opposite direction, thus stabilizing the binocular fixation point.
The nurse is performing her morning assessment on a 69-year-old client on a medical-surgical unit. Upon assessing her pupils the nurse notices that they are equal and responsive to light but not to accommodation. The nurse is aware that with aging the lens becomes thicker and its capsule less elastic so she believes this to be the case. When accommodation is diminished in an older person as a result of aging this is referred to as:
presbyopia. Explanation: The term presbyopia refers to a decrease in accommodation that occurs because of aging. Hyperopia is the same as farsightedness and myopia refers to nearsightedness (when the person can see close objects without problems but distant objects are blurred).
A 69-year-old client comes to the clinic for a routine checkup. Upon examination, the nurse practitioner informs the client that she has cataracts. The client then tells the nurse that she already knew that and her physician told her that she could use bifocals and that would take care of the problem. What would be the best response by the nurse practitioner?
"Surgery is the only effective treatment for cataracts." Explanation: There is no effective medical treatment for cataract. Strong bifocal lenses, magnification, appropriate lighting, and visual aids may be used as the cataract progresses, but surgery is the only treatment for correcting cataract-related vision loss. Telling the client that bifocals will cure cataracts is false as well as telling her that her doctor was correct. The other option is not a therapeutic response by the nurse.
A client has shingles. What is the best time frame for the initiation of oral and intravenous antiviral drugs after the appearance of a rash to reduce the incidence of ocular complication?
3 days Explanation: Treatment includes the use of oral and intravenous antiviral drugs. Initiation of treatment within the first 72 hours after the appearance of the rash reduces the incidence of ocular complications but not the postherpetic neuralgia. Reference:
A member of the military is preparing for a mission that requires scotopic vision. How long does the client have to be in total or near total darkness to increase rod sensitivity to the optimum level?
4 hours Explanation: Dark adaptation is the process by which rod sensitivity increases to the optimum level. This requires approximately 4 hours in total or near-total darkness and is referred to as scotopic vision (night vision).
A client has been diagnosed with a cataract and wants to know what percentage of individuals get cataracts. The client is 78 years old. What percentage of clients over the age of 75 have cataracts?
70% Explanation: Cataracts are the most common cause of blindness in the world, accounting for nearly 48 percent of all blindness. Aging is the most common cause of cataracts, with an estimated prevalence of 50 percent in persons between the ages of 65 and 74 years, and increasing to 70 percent in those over 75 years of age.
A client presents with copious amounts of yellow-green drainage, conjunctival redness, and chemosis to the right eye. A culture of the eye drainage reveals S. pneumoniae. The client most likely developed:
Bacterial conjunctivitis Explanation: Based on the presenting symptoms and the culture results, this is classic bacterial conjunctivitis. Allergic and chronic conjunctivitis usually involves both eyes.
Damage to which part of the eye is responsible for loss of color vision?
Central retina Explanation: The blood supply for the retina is derived from the central retinal artery, which supplies blood flow for the entire inside of the retina. As with a camera, the simple lens system of the eye inverts the image of the external world on each retina. Errors in refraction occur when the visual image is not focused on the retina because of individual differences in the size or shape of the eyeball or cornea.
An older client is complaining of having difficulty seeing. The nurse suspects that the client has cataracts. What are the common manifestations of a cataract? Select all that apply.
Increasingly blurred vision Visual distortion Explanation: Age-related cataracts, which are the most common type, are characterized by increasingly blurred vision and visual distortion. Visual acuity for far and near objects decreases. Dilation of the pupil in dim light improves vision. With nuclear cataracts (those involving the lens nucleus), the refractive power of the anterior segment often increases to produce an acquired myopia.
Amblyopia, or lazy eye, occurs at a time when visual deprivation or abnormal binocular interactions occur in visual infancy. Whether amblyopia is reversible depends on which factor?
Maturity of the visual system at time of onset. Explanation: The reversibility of amblyopia depends on the maturity of the visual system at the time of onset and the duration of the abnormal experience.
Causes of eyelid weakness include neurologic causes. There can be damage to the cranial nerves (CN) that innervate the eyelids, or there can be damage to the central nuclei of the cranial nerves. Where are the central nuclei of cranial nerve III (oculomotor nerve) and CN VII (facial nerve)?
Midbrain and caudal pons Explanation: Neurologic causes of eyelid weakness include damage to the innervating cranial nerves or to the nerve's central nuclei in the midbrain and the caudal pons. The other answers are not related to the central nuclei of the oculomotor and the facial nerves.
A client who is being treated in the critical care unit is experiencing a slowing of blood flow to the central retinal artery, ultimately resulting in edema of the client's optic papilla. Which assessment would most likely address the etiology of this health problem?
Monitoring of the client's intracranial pressure Explanation: The client is experiencing papilledema, which is most often caused by an increase in ICP. It is noninfectious and is unrelated to systemic blood pressure or lymphedema.
Cortical blindness is the bilateral loss of the primary visual cortex. What is retained in cortical blindness?
Pupillary reflexes Explanation: Crude analysis of visual stimulation at reflex levels, such as eye- and head-orienting responses to bright moving lights, pupillary reflexes, and blinking at sudden bright lights, may be retained even though vision has been lost.
The parents of a 6-month-old child who was born with a blocked tear duct are concerned because their child has been waking up the past few mornings with inflammation in the left eye and yellow, dried secretions preventing eye opening in spite of massaging the tear duct. The nurse would anticipate which of the following?
The child has developed dacryocystitis. Explanation: Some babies are born without spontaneous opening of the tear duct(s) before birth, causing the inability of the tears to drain and increasing the risk of infection of the lacrimal sac (dacryocystitis). Signs and symptoms of dacryocystitis include excess secretions in the affected eye, which may cause crusting; excessive tearing; swelling; pain; and tenderness. The initial treatments would include warm compresses to the affected eye, antibiotics, and if appropriate, analgesics. Consideration of surgical probing of the tear duct is reserved for chronic cases of dacryocystitis.
Age-related macular degeneration that is dry is characterized by:
atrophy of the Bruch membrane. Explanation: Nonexudative age-related macular degeneration is characterized by various degrees of atrophy and degeneration of the outer retina, Bruch membrane, and choriocapillary layer (choriocapillaris) of the choroid. It does not involve leakage of blood or serum; hence, it is called dry age-related macular degeneration. The other answers are characterizations of the "wet" form of macular degeneration.
A client who experiences constant cloudiness of vision, sees floaters, and has an opaque lens is diagnosed with a cataract. The most appropriate treatment would be:
surgical lens replacement to correct vision. Explanation: Although strong bifocal lenses, magnification, appropriate lighting, and visual aids may help, surgery is the only treatment for cataract.
During a routine 2-month checkup at the pediatric clinic, a mother expresses concern that her son looks "cross-eyed." She asks if she needs to put patches over his good eye. Assessment reveals full eye movement, and the child uses each eye independently. The health care provider explains that the best treatment for the infant's eye problem is:
to prepare for some surgery to correct this problem early in life in order to correct the eye muscle disorder. Explanation: The disorder may be nonaccommodative, accommodative, or a combination of the two. Infantile esotropia is the most common cause of nonaccommodative strabismus. It occurs in the first 6 months of life, with large-angle deviations, in otherwise developmentally and neurologically normal infants. Eye movements are full, and the child often uses each eye independently to alter fixation (cross-fixation). Infantile esotropia is usually treated surgically by weakening the medial rectus muscle on each eye while the infant is under general anesthesia. Recurrences are common with infantile esotropia, and multiple surgeries are often required.
A client presents with varicella predominately occuring from the top of the nose to the eyelid margins. Which further assessments correlate to the development of varicella-zoster ophthalmicus? Select all that apply.
uveitis with elevated intraocular pressure of 32 mm Hg tearing of the eye and photophobia eye pain and vesicular rash Explanation: Herpes zoster ophthalmicus usually presents with malaise, fever, headache, and burning and itching of the periorbital area. These symptoms commonly precede the ocular eruption by a day or so. The rash is initally vesicular, becomes pustular and then crusts. Involvement of the tip of the nose and lid margins indicates a high likelihood of ocular involvement. Ocular signs include conjunctivitis, keratitis (irritation tearing and photophobia), and anterior uveitis, often with elevated intraoccular pressure. Bruising is not common with this diagosis. Bulging of the eye orbit (exophthalmos) is usually associated with thyroid problems (hyperthyroidism).
Vitreous humor occupies the posterior portion of the eyeball. It is an amorphous biologic gel. When liquefaction of the gel occurs, as in aging, what can be seen during head movement?
Floaters Explanation: With the loss of gel structure, fine fibers, membranes, and cellular debris develop. When this occurs, floaters (images) can often be noticed because these substances move within the vitreous cavity during head movement. Blind spots, meshlike structures, and red spots are not seen during head movement with a loss of the gel structure of the vitreous humor.
The nurse is conducting a community education class on amblyopia. The nurse determines that the participants understand the concepts when they identify which time period as the time when amblyopia is generally diagnosed?
Infancy Explanation: Amblyopia (i.e., lazy eye) is a decrease in visual acuity resulting from abnormal visual development in infancy and early childhood. There is no known connection between the condition and either injury or diabetes.
The cornea functions as a protective membrane. What layers of tissues form the cornea? Select all that apply.
Outer epithelial layer Substantia propria or stroma Inner endothelial layer Explanation: Three layers of tissue form the cornea: an extremely thin outer epithelial layer, which is continuous with the bulbar conjunctiva; a middle layer called the substantia propria or stroma; and an inner endothelial layer, which lies next to the aqueous humor of the anterior chamber. The three layers of the cornea are separated by two important basement membranes: Bowman and Descemet membranes.
Cortical blindness is the bilateral loss of the primary visual cortex. What is retained in cortical blindness?
Pupillary reflexes Explanation: Crude analysis of visual stimulation at reflex levels, such as eye- and head-orienting responses to bright moving lights, pupillary reflexes, and blinking at sudden bright lights, may be retained even though vision has been lost.
A mother brings her toddler to the clinic and tells the nurse that she thinks something is wrong with the baby's eyes. Upon further assessment the nurse notices that the child has upper deviation in movement in only one eye. What diagnosis should the nurse suspect for this child?
Strabismus Explanation: Strabismus, or squint, refers to any abnormality of eye coordination or alignment that results in loss of binocular vision. Amblyopia refers to lazy eye. Glaucoma is a chronic degenerative optic neuropathy. Cataract affects the lens of the eye.
A client develops fever, headache, and burning/itching in the periorbital area. After a few days, a vesicular rash appears around the eyelid margins. The health care provider will likely prescribe:
antiviral medication for herpes zoster ophthalmicus. Explanation: Herpes zoster ophthalmicus usually presents with malaise, fever, headache, and burning and itching of the periorbital area. These symptoms commonly precede the ocular eruption by a day or two. The rash, which is initially vesicular, becomes pustular and then develops crusts. Treatment includes the use of oral and intravenous antiviral drugs. Initiation of treatment within the first 72 hours after the appearance of the rash reduces the incidence of ocular complications but not the postherpetic neuralgia. Chlamydial conjunctivitis is commonly spread by contact with genital secretions. It is treated with antimicrobial medications. Causes of ulcerative keratitis include infectious agents, exposure to trauma, and use of extended-wear contact lenses. The first manifestations of recurrent herpes keratitis are irritation, photophobia, and tearing. A history of fever blisters or other herpetic infection is often noted. Allergic conjunctivitis encompasses a spectrum of conjunctival conditions usually characterized by itching. Allergic conjunctivitis also has been successfully treated with topical mast cell stabilizers, histamine type 1 (H1) receptor antagonists, and topical nonsteroidal anti-inflammatory drugs.
A client has been diagnosed with bacterial conjunctivitis. This type of infection is usually characterized by large amounts of what color drainage?
yellow-green Explanation: The infection usually is characterized by large amounts of yellow-green drainage. The eyelids are sticky, and there may be excoriation of the lid margins.