Diagnostic Tests for Myopia
Myopia Tests: Book Excerpts
Home Diagnostic Testing
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Myopia Diagnosis: Book Excerpts
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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.
» READ BOOK EXCERPT ONLINE »
Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
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
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.)
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
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.
» READ BOOK EXCERPT ONLINE »
Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Shortness of Breath:
Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
In the physical examination, focus on signs of respiratory or cardiac disease. For the respiratory system, this means a careful examination starting at the nose. Specifically, on head, eyes, ear, nose, and throat examination look for evidence of obstruction, infection, or postnasal drip. Exclude obstruction, subcutaneous emphysema, or tracheal deviation. On cardiac examination, look for evidence of cardiomegaly, S3 gallop, or hepatojugular reflux (HJR). In this setting, HJR is very specific for CHF (1). Assess the lungs for abnormal breath sound intensity, rales, wheezing, rhonchi, or tachypnea. Examine the chest for abnormal movements or deformities. Exclude abdominal masses, ascites, pregnancy, or abdominal distention. Evaluate the extremities for edema, tenderness, or asymmetry. Do a complete neurologic examination, and screen for weakness atrophy, sensory loss, and fasciculations.
Testing
Most patients require a CXR study and pulse oximetry to screen for cardiac and pulmonary diseases. Use an arterial blood gas (ABG) analysis to confirm hypoxia, hypercapnia, hypocapnia, and acidosis. Complete blood count (CBC), electrolytes, thyroid-stimulating hormone (TSH), and drug screens are useful for suspected cases of anemia, acidosis, hyperthyroidism, hypothyroidism, or drug ingestions.
Pulmonary function studies (PFTs) are important to document the presence of obstructive or restrictive lung diseases. A methacholine challenge test is used if the symptoms are intermittent, the patient is aged less than 40 years, or if lung disease is suspected and the PFTs are normal. In this setting, the results will confirm or exclude asthma (3). In dyspneic patients, a lung diffusion capacity (DLCO) has a high positive predictive value and a high negative predictive value for interstitial lung disease (3). Low maximal inspiratory and expiratory pressures suggest neuromuscular disease.
The cardiac causes of dyspnea are CHF, intracardiac shunts, valvular heart disease, pulmonary hypertension, and pericardial disease. They have abnormal or characteristic findings on echocardiography and Doppler echocardiography. An electrocardiogram (ECG) or exercise stress test (EST) screens for arrhythmias and ischemic heart disease. Warning: A negative EST does not exclude ischemia in dyspneic patients (3) (Chapter 7.1).
Other tests are used in selected patients. High resolution computerized tomography (CT) of the chest detects early interstitial lung disease in patients with normal CXR films. Electromyogram (EMG) and nerve conduction studies are useful for confirming and differentiating the most common neuromuscular problems: myasthenia gravis and Guillain-Barré syndrome. A therapeutic response to H2 blockers confirms gastroesophageal reflux disease (GERD) in most dyspneic patients (2). Screen for acute or chronic pulmonary embolism with a nuclear medicine ventilation and perfusion (·V/Q·) scan.
Diagnostic assessment
The initial assessment usually requires a clinical evaluation, CXR study, and pulse oximetry. This identifies about 70% of the underlying diseases (1). For the remainder, a systematic evaluation for the most common diseases will correctly identify the cause. If appropriate, consider obtaining an ECG, CBC, TSH, and electrolytes. If theses are nondiagnostic, then further testing is indicated.
Exclude pulmonary diseases if the initial evaluation is nondiagnostic, or if pulmonary diseases are suspected, which account for 75% of the cases (3). Start with PFTs and an ABG. If the PFTs are normal, then order a methacholine challenge test to rule out asthma. If interstitial lung disease is suspected or if the PFTs show a restrictive pattern, then order a DLCO. Abnormally low maximal inspiratory and expiratory pressures suggest neuromuscular disease. Confirm the diagnosis with an EMG.
When pulmonary disease has been excluded, or if cardiac disease is suspected, the next step should be a cardiac evaluation. An echocardiogram will suggest or identify most of the cardiac causes. If the echocardiogram is normal, consider exercise stress testing or a Holter monitor. If these are normal, then most patients will have either GERD, deconditioning, or psychogenic disorders. Other low frequency causes of shortness of breath that need further evaluation include neuromuscular diseases, pulmonary emboli, postnasal drip, and sleep apnea. With a clinical suspicion of these disorders, obtain an EMG, ·V/Q· scan, or polysomnogram. Otherwise, they are not indicated.
References
1. Mulrow CD, Lucey CR, Farnett LE. Discriminating causes of dyspnea through clinical examination. J Gen Intern Med 1993;8:383–392.
2. DePaso WJ, Winterbauer RH, Lusk JA, Dreis DF, Springmeyer SC. Chronic dyspnea unexplained by history, physical examination, chest roentgenogram, and spirometry. Chest 1991;100:1293–1299.
3. Pratter MR, Curley FJ, Dubois J, Irwin RS. Cause and evaluation of chronic dyspnea in a pulmonary disease clinic. Arch Intern Med 1989;149:2277–2282.
4. Schmitt BP, Kushner MS, Wiener SL. The diagnostic usefulness of the history of the patient with dyspnea. J Gen Intern Med 1986;1:386–393.
5. Mahler DA, Harver A, Lentine T, Scott JA, Beck K, Schwartzstein M. Descriptors of breathlessness in cardiorespiratory diseases. Am J Respir Crit Care Med 1996;154:1357–1363.
» READ BOOK EXCERPT ONLINE »
Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
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
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.)
» READ BOOK EXCERPT ONLINE »
Source: Nursing: Interpreting Signs and Symptoms, 2007
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