Diagnostic Tests for Blindness
Blindness Tests: Book Excerpts
Home Diagnostic Testing
These home medical tests may be relevant to Blindness:
- Vision & Eye Health: Home Testing:
Blindness Diagnosis: Book Excerpts
Diagnosis of Blindness: medical news summaries:
The following medical news items
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Diagnostic Tests for Blindness: Online Medical Books
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Review excerpts from medical books online, free, without registration,
for more information about the diagnostic tests for Blindness.
EYE PAIN:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
The primary care specialist may want to treat cases of obvious conjunctivitis without a culture and sensitivity. However, a smear and culture is useful especially if
Neisseria
is suspected. A smear may also reveal eosinophils suggesting allergic conjunctivitis. The primary care specialist may also use fluorescein dye to diagnose a foreign body. Most primary care physicians feel competent to use tonometry to diagnose glaucoma and may feel competent to use a slit lamp. However, when there is any doubt about the diagnosis, the most cost-effective approach is to refer the patient to an ophthalmologist.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
HEMIANOPSIA:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
Referral to an ophthalmologist for a thorough visual field examination is suggested at the outset. A neurology consultation also needs to be obtained. The neurologist will probably order a CT scan of the brain to rule out a space-occupying lesion unless multiple sclerosis is suspected.
If multiple sclerosis is suspected, MRI would be the study of choice, even though it is more expensive. In addition, VEP studies and spinal fluid analysis may be ordered to rule out multiple sclerosis.
A carotid duplex scan will help diagnose carotid vascular insufficiency, but four-vessel cerebral angiography will most likely be done so that both carotid and vertebral basilar artery disease can be evaluated. If there are endocrine changes, an endocrinologist should be consulted.
If a cerebral embolism is suspected, a source for the embolism should be sought. A cardiologist can best determine what tests to order to search for an embolic source.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
PAPILLEDEMA:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
Regardless of whether there are focal neurologic signs or hypertension, a CT scan or MRI should be done, and a consultation with a neurologist should be made when papilledema is suspected.
If there is significant hypertension and the CT scan or MRI are negative, a hypertensive workup should be done
.
With a normal CT scan or MRI and no focal neurologic signs or hypertension, a spinal tap and visual field examination will assist in the diagnosis of pseudotumor cerebri. However, a blood lead level should be done to rule out lead poisoning. Also, the visual field exam may show optic neuritis when the clinical examination was inconclusive.
An ophthalmologist will help diagnose optic neuritis and pseudopapilledema.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
SCOTOMA:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
This should include a careful eye examination with slit lamp, tonometry, and visual field examinations. If the initial findings suggest an ocular disorder, referral to an ophthalmologist should be made. If the neurologic examination is abnormal, the patient should be referred to a neurologist, rather than ordering expensive tests such as a CT scan, MRI scan, VEP studies, angiography, and spinal fluid examinations.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
BLINDNESS:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
Referral to an ophthalmologist is usually the first step in a good workup. If one is not available, a careful eye examination including slit lamp examination, visual acuity evaluation, tonometry, and visual field studies should be done. If these are unrevealing, a referral to an ophthalmologist or neurologist should be made without further delay. Additional studies would include a CT scan or MRI of the brain and orbits, carotid scans, spinal tap, VEP studies, and four-vessel cerebral angiography. An EEG would be useful in diagnosing hysterical blindness and malingering.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
GAIT DISTURBANCES:
DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)
Routine orders would include a CBC, sedimentation rate, chemistry panel, VDRL test, and urinalysis. If there is a painful limp, x-rays of the hip, knee, or ankle on the affected side should be performed. An x-ray of the lumbar spine will not usually be of great assistance, however. If plain x-rays are negative, a CT scan or MRI of the lumbar spine, hip, knee, or ankle may be of assistance in the diagnosis. A bone scan may pick up obscure fractures and other pathology.
If there are abnormalities on the neurologic examination, MRI or CT scan of the appropriate level of suspected pathology will be done. A spastic gait with abnormal cranial nerve findings would suggest a cerebral tumor or other brain disease, and a CT scan or MRI of the brain should be done. Keep in mind that the MRI is almost double the cost of a CT scan, and the diagnostic yield is not that much greater in many cases.
A spastic gait without cranial nerve signs or papilledema would suggest a spinal cord disorder, and an MRI or CT scan of the appropriate level of the spinal cord should be done. A CT scan of the cervical spine, however, is not very useful and MRI is preferred.
If multiple sclerosis is suspected, a spinal tap for myelin basic protein or gamma globulin levels should be done. A VEP study, a BSEP study, or a SSEP study will also be useful in diagnosing multiple sclerosis.
If there is an ataxic gait, cerebellar disorder should be suspected, and a CT scan of the brain may be done. However, an ataxic gait may also suggest multiple sclerosis, pernicious anemia, and tabes dorsalis. If the VDRL test is negative, a FTA-ABS test should be done. Blood levels for vitamin B
12
and folic acid will help diagnose pernicious anemia. A Schilling test, however, is sometimes necessary to facilitate this diagnosis. If muscular dystrophy is suspected, electromyographic examination and muscle biopsy will help confirm the diagnosis. If the patient has a steppage gait, the workup of peripheral neuropathy should be done, as noted on
page 350
.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
Eye pain:
History and physical examination
(Handbook of Signs & Symptoms (Third Edition))
If the patient's eye pain doesn't result from a chemical burn, take a complete history. Have the patient describe the pain fully. Is it an ache or a sharp pain? How long does it last? Is it accompanied by burning, itching, or discharge? Find out when it began. Is it worse in the morning or late in the evening? Ask about recent trauma or surgery, especially if the patient complains of sudden, severe pain. Does he have headaches? If so, find out how often and at what time of day they occur.
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Source: Handbook of Signs & Symptoms (Third Edition), 2006
Hemianopsia:
History and physical examination
(Handbook of Signs & Symptoms (Third Edition))
Suspect a visual field defect if the patient seems startled when you approach him from one side or if he fails to see objects placed directly in front of him. To help determine the type of defect, compare the patient’s visual fields with your own — assuming that yours are normal. First, ask the patient to cover his right eye while you cover your left eye. Then move a pen or similarly shaped object from the periphery of his (and your) uncovered eye into his field of vision. Ask the patient to indicate when he first sees the object. Does he see it at the same time you do? After you do? Repeat this test in each quadrant of both eyes. Then, for each eye, plot the defect by shading the area of a circle that corresponds to the area of vision loss.
Next, evaluate the patient’s level of consciousness (LOC), take his vital signs, and check his pupillary reaction and motor response. Ask if he has recently experienced a headache, dysarthria, or seizures. Does he have ptosis or facial or extremity weakness? Hallucinations or loss of color vision? When did neurologic symptoms start? Obtain a medical history, noting especially eye disorders, hypertension, diabetes mellitus, and recent head trauma.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Signs & Symptoms (Third Edition), 2006
Scotoma:
History and physical examination
(Handbook of Signs & Symptoms (Third Edition))
First, identify and characterize the scotoma, using such visual field tests as the tangent screen examination, the Goldmann perimeter test, and the automated perimetry test. Two other visual field tests — confrontation testing and the Amsler grid — may also help in identifying a scotoma.
Next, test the patient’s visual acuity and inspect his pupils for size, equality, and reaction to light. An ophthalmoscopic examination and measurement of intraocular pressure are necessary.
Explore the patient’s medical history, noting especially eye disorders, vision problems, or chronic systemic disorders. Find out if he takes medications or uses eyedrops.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Signs & Symptoms (Third Edition), 2006
Vision loss:
History and physical examination
(Handbook of Signs & Symptoms (Third Edition))
Sudden vision loss can signal an ocular emergency. (See Managing sudden vision loss.) Don’t touch the eye if the patient has perforating or penetrating ocular trauma.
If the patient’s vision loss occurred gradually, ask him if the vision loss affects one eye or both and all or only part of the visual field. Is the visual loss transient or persistent? Did the visual loss occur abruptly, or did it develop over hours, days, or weeks? What is the patient’s age? Ask the patient if he has experienced photosensitivity, and ask him about the location, intensity, and duration of any eye pain. You should also obtain an ocular history and a family history of eye problems or systemic diseases that may lead to eye problems, such as hypertension; diabetes mellitus; thyroid, rheumatic, or vascular disease; infections; and cancer.
The first step in performing the eye examination is to assess visual acuity, with best available correction in each eye. (See Testing visual acuity, page 630.)
Carefully inspect both eyes, noting edema, foreign bodies, drainage, or conjunctival or scleral redness. Observe whether lid closure is complete or incomplete, and check for ptosis. Using a flashlight, examine the cornea and iris for scars, irregularities, and foreign bodies. Observe the size, shape, and color of the pupils, and test the direct and consensual light reflex (See “Pupils, nonreactive,” page 521.) and the effect of accommodation. Evaluate extraocular muscle function by testing the six cardinal fields of gaze. (See Testing extraocular muscles, page 206.)
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Signs & Symptoms (Third Edition), 2006
Hemianopsia:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
Suspect a visual field defect if the patient seems startled when you approach him from one side or if he fails to see objects placed directly in front of him. To help determine the type of defect, compare the patient’s visual fields with your own—assuming that yours are normal. First, ask the patient to cover his right eye while you cover your left eye. Then move a pen or similarly shaped object from the periphery of his (and your) uncovered eye into his field of vision. Ask the patient to indicate when he first sees the object. Does he see it at the same time you do? After you do? Repeat this test in each quadrant of both eyes. Then, for each eye, plot the defect by shading the area of a circle that corresponds to the area of vision loss.
Next, evaluate the patient’s level of consciousness (LOC), take his vital signs, and check his pupillary reaction and motor response. Ask if he has recently experienced headache, dysarthria, or seizures. Does he have ptosis or facial or extremity weakness? Hallucinations or loss of color vision? When did his neurologic symptoms start? Obtain a medical history, noting especially eye disorders, hypertension, diabetes mellitus, and recent head trauma.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Scotoma:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
First, identify and characterize the scotoma, using such visual field tests as the tangent screen examination, the Goldmann perimeter test, and the automated perimetry test. Two other visual field tests—confrontation testing and the Amsler grid—may also help in identifying a scotoma.
Next, test the patient’s visual acuity and inspect his pupils for size, equality, and reaction to light. An ophthalmoscopic examination and measurement of intraocular pressure (IOP) are necessary.
Explore the patient’s medical history, noting especially any eye disorders, vision problems, or chronic systemic disorders. Find out if he takes medications or uses eyedrops.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Vision loss:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
Sudden vision loss can signal an ocular emergency. Don’t touch the eye if the patient has a perforating or penetrating ocular trauma. (See Managing sudden vision loss, page 802.)
If the patient’s vision loss occurred gradually, ask him if it affects one eye or both and all or only part of the visual field. Is the vision loss transient or persistent? Did it occur abruptly or develop over hours, days, or weeks? What is the patient’s age? Ask the patient if he has experienced photosensitivity, and ask about the location, intensity, and duration of any eye pain. Also, obtain an ocular history and a family history of eye problems or systemic diseases that may lead to eye problems, such as hypertension; diabetes mellitus; thyroid, rheumatic, or vascular disease; infections; and cancer.
The first step in performing the eye examination is to assess visual acuity with the best available correction in each eye. (See Testing visual acuity, page 803.)
Carefully inspect both eyes, noting edema, foreign bodies, drainage, or conjunctival or scleral redness. Observe whether lid closure is complete or incomplete, and check for ptosis. Using a flashlight, examine the cornea and iris for scars, irregularities, and foreign bodies. Observe the size, shape, and color of the pupils, and test the direct and consensual light reflex (see “Pupils, nonreactive,” page 654) and the effect of accommodation. Evaluate extraocular muscle function by testing the six cardinal fields of gaze. (See Testing extraocular muscles, page 246.)
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Night blindness [Nyctalopia]:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
If the patient complains of difficulty seeing at night, ask when he first noticed the problem. Is it intermittent or steadily worsening? Is it worse at certain times or in certain conditions? Also, ask about other ocular symptoms, such as eye pain, blurred or halo vision, floaters or spots, and photophobia.
Explore any history of glaucoma, cataracts, and familial degeneration of vision. If no ocular problems are apparent, briefly evaluate the patient’s nutritional status for vitamin A deficiency.
Examine the eyes for ptosis, abnormal tearing, discharge, and conjunctival injection. Test visual acuity and visual fields in both eyes and, if trained and equipped, measure intraocular pressure. Check pupillary response, and evaluate extraocular muscle function by testing the six cardinal fields of gaze.
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Eye pain [Ophthalmalgia]:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
If the patient’s eye pain doesn’t result from a chemical burn or from acute angle-closure glaucoma, take a complete history. Have the patient describe the pain fully. Is it an ache or a sharp pain? How long does it last? Is it accompanied by burning, itching, or a discharge? Find out when it began. Is it worse in the morning or late in the evening? Ask about recent trauma or surgery, especially if the patient complains of severe pain that developed suddenly. Does he have headaches? If so, find out how often and at what time of day they occur.
During the physical examination, don’t manipulate the eye if you suspect trauma. Carefully assess the eyelids and conjunctivae for redness, inflammation, and swelling. Then examine the eyes for ptosis or exophthalmos. Finally, test visual acuity with and without correction, and assess extraocular movements. Characterize any discharge. (See Examining the external eye, page 322.)
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Papilledema:
Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A focused physical examination should include vital signs, such as blood pressure. Examine the head: check for neck stiffness, temporal artery tenderness, pain in and around the eyes, and pain on ocular rotations, such as occurs in optic neuritis. Afferent pupillary defect is another red flag that almost always signifies an ocular cause of disc edema, retinal vein occlusion, anterior ischemic optic neuropathy, or optic neuritis. Always examine both eyes. Normally papilledema is bilateral, but can be present asymmetrically. In true disc edema, nerve fiber layer swelling is seen, which obscures the margins of the blood vessels. Tiny splinter hemorrhages will be seen in and around the optic nerve. If the other eye has no disc swelling, look for spontaneous venous pulsations (SVP). If these SVPs are present, there is normal intracranial pressure, therefore, no true papilledema. Very prominent retinal hemorrhages suggest malignant hypertension or central retinal vein occlusion, rather than papilledema. Disc elevation can be measured using the diopteric overcorrection in the direct ophthalmoscope. Basically, focus on the retina and add in plus (red) power until the optic nerve blurs. Three diopters equals 1 mm of elevation. Ocular rotations are limited in both third and sixth nerve palsy. Sixth nerve palsies show limited lateral gaze and third nerve palsies have limitation in medial gaze, elevation, and depression. When ptosis and a dilated pupil are seen, suspect an aneurysm at the posterior communicating artery in the circle of Willis as the underlying cause. Decreased visual acuity is another red flag and normally is only mildly depressed in true papilledema. If the vision is decreased severely, look for other causes that are not related to increased intracranial pressure.
Testing
A. Laboratory studies. If disc edema is found, suggested laboratory tests include sedimentation rate and C-reactive protein for temporal arteritis; white blood count to rule out underlying infection and leukemic infiltration of the optic nerve; a computed tomography (CT) or magnetic resonance imaging (MRI) scan to rule out a compressive lesion; cerebrospinal fluid (CSF) examination for signs of meningitis, tumor, or hemorrhage only after ruling out a compressive lesion with a scan.
B. Diagnostic imaging. If true papilledema is suspected, diagnostic imagining is mandatory. A CT scan with and without contrast should be ordered, possibly followed by MRI and MRI angiography, if the CT scan is inconclusive. MRI will be particularly helpful in imaging brainstem and cerebellar lesions, which can obstruct CSF flow. Despite the greater cost of the MRI and the greater specificity of intracranial pathology, the CT scan still is the preferred technique to image acute bleeding intracranially.
Diagnostic assessment
The critical workup in papilledema includes an accurate history and assessment of the visual system. Vision is often not significantly impaired in true papilledema; if present, it would suggest seeking other causes. An afferent pupillary defect indicates a localized optic nerve or retinal condition as the cause. A detailed examination of the optic nerve to look for optic nerve drusen or pseudopapilledema is also important. The finding of spontaneous venous pulsation indicates normal intracranial pressure and no imaging is mandatory. However, if absent, this does not rule out normal intracranial pressure. No imaging is mandatory; however, if needed, a lumbar puncture should be performed following imaging. Treatment should be directed toward the underlying cause of the elevated intracranial pressure.
References
1. Gordon RN, Burde RM, Slamovits T. Asymptomatic optic disc edema. J Neuroophthalmol 1997;17(1):29–32.
2. Hedges TR. Bilateral visual loss in a child with disc swelling. Surv Ophthalmol 1992;
36(6):424–428.
3. Moster ML. Unilateral disk edema in a young woman. Surv Ophthalmol 1995;39(5):
409–416.
4. Wall M. Optic disc edema with cotton-wool spots. Surv Ophthalmol 1995;39(6):
502–508.
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Scotoma:
Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A. Visual acuity. The vision of each eye should be assessed with spectacles or contact lenses in each eye independently. Central scotomas are seen with optic nerve, macular disease, or (rarely) an occipital tip lesion; and Snellen visual acuity will be decreased.
B. Visual fields. Confrontation field test is performed with each eye independently. Briefly flash several fingers in each of the four quadrants. Bilateral field loss in the same field of vision in each eye indicates injury posterior to the chiasm. Bitemporal field defects are seen with chiasmal lesions (pituitary masses, craniopharyngiomas, and others). Monocular field defects are seen in retina and optic nerve disease.
C. Pupil examination. The presence of a prominent APD, which implies optic nerve injury, will help to differentiate central scotomas caused by macular disease. An APD is commonly seen with optic neuritis, optic neuropathy (ischemic and traumatic), asymmetric glaucomatous damage, optic nerve tumors, and central retinal artery or vein occlusion. An APD is not seen in early papilledema and minimally with macular degeneration, macular holes, or choroidopathy.
D. Fundus examination. Direct ophthalmoscopy can give a quick assessment of the red reflex (i.e., a dim red reflex in a diabetic with vitreous hemorrhage). Vitreous floaters can occasionally be seen as shadows in the red reflex. Examine the nerve for edema, pallor, or glaucomatous cupping. Macular scarring or pigmentary change is most commonly seen with macular degeneration.
E. Other examinations. A neurologic assessment is needed for a patient with bilateral field loss, screening for contralateral paresis and other focal deficits, palpation of the temporal artery for tenderness or diminished pulse if the history suggests giant cell arteritis, as is auscultation of the carotids for bruits and the heart for a murmur in a patient with amaurosis fugax or stroke. Glaucoma can be screened with tonometry. Check arms and legs for signs of intravenous drug abuse.
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Eye Pain:
Diagnostic Approach
(Field Guide to Bedside Diagnosis)
A foreign body sensation occurs with a foreign body, corneal abrasion, or keratoconjunctivitis sicca. Itching is associated with allergic and vernal conjunctivitis. Photophobia occurs with iritis and herpes simplex keratitis. Deep pain suggests acute glaucoma or posterior scleritis. Pain on eye movement is found with optic neuritis, sinusitis, and influenza.
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Source: Field Guide to Bedside Diagnosis, 2007
Visual Disturbance:
Diagnostic Approach
(Field Guide to Bedside Diagnosis)
Homonymous hemianopsia may be perceived as blurring or as trouble finding the start of a line of print. On closer inspection, visual loss in corresponding fields in both eyes will be detected. This usually results from a lesion in the suprageniculate pathway. The macula is usually spared in cortical lesions. Bitemporal hemianopsia is due to a chiasmal lesion such as a pituitary adenoma, anterior communicating artery aneurysm, cerebellar tumor with third ventricle hydrocephalus, or meningitis. Thiamine deficiency, methanol toxicity, or optic neuritis at the chiasm can cause true acute bilateral visual loss
An afferent pupillary defect (Marcus Gunn pupil) is diagnostic for a prechiasmal optic nerve lesion. Have the patient fixate on a far object, and then shine a bright light into his or her eyes. The initial (abnormal) response is dilation instead of brisk contraction.
Tunnel vision causes a patient to turn his or her head to avoid bumping into objects, and it can be outlined by visual field confrontation. Causes include glaucoma, retinitis pigmentosa, and quinine toxicity.
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Source: Field Guide to Bedside Diagnosis, 2007
Eye pain:
Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
During the physical examination, don’t manipulate the eye if you suspect trauma. Carefully assess the lids and conjunctivae for redness, inflammation, and swelling. Then examine the eyes for ptosis or exophthalmos. Finally, test visual acuity with and without correction, and assess extraocular movements. Characterize any discharge. (See Examining the external eye, page 272.)
» READ BOOK EXCERPT ONLINE »
Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Hemianopsia:
Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Evaluate the patient’s level of consciousness (LOC), take his vital signs, and check his pupillary reaction and motor response. Does he have ptosis or facial or extremity weakness? Hallucinations or loss of color vision?
» READ BOOK EXCERPT ONLINE »
Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Scotoma:
Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Test the patient’s visual acuity and inspect his pupils for size, equality, and reaction to light. An ophthalmoscopic examination and measurement of intraocular pressure (IOP) are necessary. Then identify and characterize the scotoma using such visual field tests as the tangent screen examination, the Goldmann perimeter test, and the automated perimetry test. Two other visual field tests — confrontation testing and the Amsler grid — may also help in identifying a scotoma.
» READ BOOK EXCERPT ONLINE »
Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Vision loss:
Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Don’t touch the patient’s eye if he has perforating or penetrating ocular trauma. The first step in performing the eye examination is to assess visual acuity, with best available correction in each eye. (See Testing visual acuity, page 691.)
Carefully inspect both eyes, noting edema, foreign bodies, drainage, or conjunctival or scleral redness. Observe whether lid closure is complete or incomplete, and check for ptosis. Using a flashlight, examine the cornea and iris for scars, irregularities, and foreign bodies. Observe the size, shape, and color of the pupils, and test the direct and consensual light reflex (see “Pupils, nonreactive,” page 551) and the effect of accommodation. Evaluate extraocular muscle function by testing the six cardinal fields of gaze.
» READ BOOK EXCERPT ONLINE »
Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Night blindness:
Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Examine the eyes for ptosis, abnormal tearing, discharge, and conjunctival injection. Test visual acuity and visual fields in both eyes and, if trained and equipped, measure intraocular pressure. Check pupillary response, and evaluate extraocular muscle function by testing the six cardinal fields of gaze.
» READ BOOK EXCERPT ONLINE »
Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Vision Disturbances:
Diagnostic Approach
(The Diagnostic Approach to Symptoms and Signs in Pediatrics)
Goal ofprimary care physician is to detect any vision disturbance and torefer child to ophthalmologist for further evaluation and treatment.Normal visual acuity is estimated tobe 20/400 at birth. By 1 yr of age, acuity improves to 20/30as determined by sophisticated electrophysiologic and psychophysiologictechniques. By 2–3 yrs of age, some children have objectivevisual acuity of 20/40–20/50. 4-yr-oldscan usually read 20/30–20/40, whereas5-yr-olds should be reading 20/20–20/30.Any child with 2 or more lines of differencebetween the eyes should be suspected of having amblyopia. Neonates
Direct ophthalmoscope should be used to checkred reflex, which is reflection of light from retina. Color andintensity of reflex should be same in each eye. Mild eye misalignmentcan be normal finding at this age and usually disappears by 2 mosof age.
Infants
By 2–3mos, eyes of infants should be straight and they should be ableto follow large objects. At each visit red reflex should alwaysbe checked. Any difference in this reflex can indicate several eyeproblems, and ophthalmologic referral is mandatory.Corneal light reflex test can be usedto distinguish strabismus from pseudostrabismus. Reflection of lightsource (e.g., penlight or direct ophthalmoscope) should be in sameposition in each pupil. Normally, this reflection is just nasalof center of each pupil. If there is difference in its positionbetween 2 pupils, strabismus is present and referral is necessary. Preverbal Children
Exam forstrabismus is important at each well-child visit. In most instancesstrabismus occurs before 3 yrs of age.Esotropia (eye turning in) usuallyoccurs when child is looking at something near (e.g., picture ortoy), whereas exotropia (eye turning out) usually occurs when childis looking at object >10 ft away.Corneal light reflex and cover testscan be used to screen for these problems (see section on Strabismus). If ocularmisalignment is found, child should be referred to ophthalmologistfor further evaluation. Verbal Children
For children≥3 yrs of age, vision can be screened by several tests usingLea symbols, Tumbling E, the letters "HOTV", Snellennumbers or letters, and Allen recognition figures.Important to determine visual acuityof each eye and any difference in vision between the eyes, evenif it is just 1 line on chart.Child with vision of 20/40in both eyes or worse or difference of 2 lines in vision between theeyes should be referred for ophthalmologic evaluation.
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Source: The Diagnostic Approach to Symptoms and Signs in Pediatrics, 2006
Hemianopsia:
History and physical examination
(Nursing: Interpreting Signs and Symptoms)
Suspect a visual field defect if the patient seems startled when you approach him from one side or if he fails to see objects placed directly in front of him. To help determine the type of defect, compare the patient's visual fields with your own—assuming that yours are normal. First, ask the patient to cover his right eye while you cover your left eye. Then move a pen or similarly shaped object from the periphery of his (and your) uncovered eye into his field of vision. Ask the patient to indicate when he first sees the object. Does he see it at the same time you do? After you do? Repeat this test in each quadrant of both eyes. Then, for each eye, plot the defect by shading the area of a circle that corresponds to the area of vision loss.
Next, evaluate the patient's level of consciousness (LOC), take his vital signs, and check his pupillary reaction and motor response. Ask if he has recently experienced a headache, dysarthria, or seizures. Does he have ptosis or facial or extremity weakness? Hallucinations or loss of color vision? When did neurologic symptoms start? Obtain a medical history, noting especially eye disorders, hypertension, diabetes mellitus, and recent head trauma.
» READ BOOK EXCERPT ONLINE »
Source: Nursing: Interpreting Signs and Symptoms, 2007
Scotoma:
History and physical examination
(Nursing: Interpreting Signs and Symptoms)
Explore the patient's medical history, noting especially eye disorders, vision problems, or chronic systemic disorders. Find out if he takes medications or uses eyedrops.
Identify and characterize the scotoma, using such visual field tests as the tangent screen examination, the Goldmann perimeter test, and the automated perimetry test. Two other visual field tests—confrontation testing and the Amsler grid—may also help in identifying a scotoma.
Next, test the patient's visual acuity and inspect his pupils for size, equality, and reaction to light. An ophthalmoscopic examination and measurement of intraocular pressure are necessary.
» READ BOOK EXCERPT ONLINE »
Source: Nursing: Interpreting Signs and Symptoms, 2007
Vision loss:
History and physical examination
(Nursing: Interpreting Signs and Symptoms)
Sudden vision loss can signal an ocular emergency. (See Managing sudden vision loss, page 628.) Don't touch the eye if the patient has perforating or penetrating ocular trauma.
If the patient's vision loss occurred gradually, ask him if the vision loss affects one eye or both and all or only part of the visual field. Is the visual loss transient or persistent? Did the vision loss occur abruptly or did it develop over hours, days, or weeks? What's the patient's age? Ask the patient if he has experienced photosensitivity and ask him about the location, intensity, and duration of eye pain. You should also obtain an ocular history and a family history of eye problems or systemic diseases that may lead to eye problems, such as hypertension; diabetes mellitus; thyroid, rheumatic, or vascular disease; infections; and cancer.
The first step in performing an eye examination is to assess visual acuity, with best available correction in each eye. (See Testing visual acuity, page 629.)
Carefully inspect both eyes, noting edema, foreign bodies, drainage, or conjunctival or scleral redness. Observe whether lid closure is complete or incomplete and check for ptosis. Using a flashlight, examine the cornea and iris for scars, irregularities, and foreign bodies. Observe the size, shape, and color of the pupils, and test the direct and consensual light reflex (See “Pupils, nonreactive,” page 515.) and the effect of accommodation. Evaluate extraocular muscle function by testing the six cardinal fields of gaze. (See Testing extraocular muscles, page 197.)
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Source: Nursing: Interpreting Signs and Symptoms, 2007
Eye pain [Ophthalmalgia]:
History and physical examination
(Nursing: Interpreting Signs and Symptoms)
If the patient's eye pain doesn't result from a chemical burn, take a complete history. Have the patient describe the pain fully. Is it an ache or a sharp pain? How long does it last? Is it accompanied by burning, itching, or discharge? Find out when it began. Is it worse in the morning or late in the evening? Ask about recent trauma or surgery, especially if the patient complains of sudden, severe pain. Does the patient wear contact lenses? How often are they removed or replaced if they're disposable? Does he have headaches? If so, find out how often and at what time of day they occur.
During the physical examination, don'tmanipulate the eye if you suspect trauma. Carefully assess the lids and conjunctiva for redness, inflammation, and swelling. Then examine the eyes for ptosis or exophthalmos. Finally, test visual acuity with and without correction, and assess extraocular movements. Characterize any discharge. (See Examining the external eye.)
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Source: Nursing: Interpreting Signs and Symptoms, 2007
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