Diagnosis of Refractive Eye Disorders
Refractive Eye Disorders Diagnosis: Book Excerpts
Diagnostic Tests for Refractive Eye Disorders: Online Medical Books
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SCOTOMA:
Ask the Following Questions:
(Algorithmic Diagnosis of Symptoms and Signs)
- Is it transient? If the scotomas are transient, then migraine, transient ischemic attacks, and retrobulbar neuritis should be suspected.
- Are there abnormalities on the eye examination other than the optic nerve? On a careful eye examination, the clinician may find corneal opacities, muscae volitantes, cataracts, choroiditis, glaucoma, retinitis, retinal hemorrhage, and detached retina.
- Are there other neurologic signs? The presence of other neurologic signs may suggest multiple sclerosis, carotid artery thrombosis or insufficiency, basilar artery thrombosis or insufficiency, and pseudotumor cerebri, among other disorders.
DIAGNOSTIC WORKUP
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
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
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
Scotoma:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
A. Nature of the scotoma. Try to establish whether the field loss is monocular or binocular. Binocular scotomas, which imply chiasmal or posterior chiasmal lesions, are vascular (stroke, transient ischemic attack, migraine, ruptured arteriovenous malformation) or compressive in nature (pituitary mass, meningioma, glioma). Establish with the patient the location of the defect. Scotomas that migrate through the visual field include vitreous floaters, vitreous hemorrhage, scintillating scotoma of migraine, and so forth. An altitudinal field loss is likely a prechiasmal lesion [i.e., optic nerve disease (e.g., ischemic optic neuropathy, glaucoma) or retina disease (e.g., detached retina, retina vascular occlusion)]. Central scotomas are commonly seen in optic nerve and macular lesions with macular degeneration by far the most common in the elderly. Macular holes, optic neuritis, toxic or metabolic optic neuropathy, central serous choroidopathy, maculopathy secondary to medications (hydroxychloroquine, thioridazine, chlorpromazine, quinine, tamoxifen), and others are examples of macular-induced central scotomas. Peripheral vision loss, if bilateral and homonymous, indicates a stroke opposite the side of field loss. Tumors, arteriovenous malformations, and migraines can cause hemianopias. Glaucoma, detached retina, retinitis pigmentosa, chronic papilledema, and previous laser treatment for diabetes are also common entities affecting peripheral vision.
B. Onset and timing of scotoma. A scotoma of sudden onset will be secondary to some kind of vascular event: embolic, hypoperfusion, inflammatory, or hemorrhagic. Transient vision loss lasting seconds can occur with temporal arteritis, papilledema, or vertebrobasilar insufficiency. Visual loss lasting minutes to hours occurs in temporal arteritis or amaurosis fugax. Visual changes lasting weeks to months represent retinal vein occlusion, expanding compressive lesion, papilledema, and if associated with pain on eye movement, optic neuritis. Gradual progressive visual field loss occurs with compressive masses; however, acute expanding lesions from infectious, inflammatory (e.g., sarcoid, Tolosa-Hunt), aneurysmal, or apoplexy of a pituitary mass can cause rapid vision loss. Monocular vision loss after head trauma suggests injury to the intracanalicular portion of the optic nerve, compressive fracture of the sphenoid bone, or edema to the optic nerve. Emergent computed tomography (CT) scan with neurosurgical or ophthalmic consultation and high-dose intravenous steroids are needed.
C. Associated symptoms. The presence of neurologic signs or symptoms can localize the area of the pathology. Amaurosis fugax implies ipsilateral internal carotid disease or cardiac disease. History of vertigo, diplopia, and urinary incontinence in a young patient with a monocular central scotoma implies multiple sclerosis. Older patients with acute monocular vision loss associated with periorbital pain and headaches, fatigue, jaw claudication, or muscle aches strongly suggests temporal arteritis. Transient dimming or loss of vision in one or both eyes with orthostatic changes can be seen with papilledema of intracranial hypertension. Progressive monocular visual loss with proptosis obviously implies an orbital mass (optic nerve glioma, meningioma, cavernous hemangioma), but asymmetric thyroid-related orbitopathy can present a similar picture. Monocular loss progressing over time without orbital signs can be seen with an intracanalicular or intracranial optic nerve mass.
D. Past medical and social history. Diabetes and hypertension are the two most common causes of ischemic optic neuropathy (ION). ION presents as a sudden painless monocular vision loss, altitudinal in nature, with an APD. The risk of retinal vascular occlusions is much greater in patients with diabetes mellitus or hypertension. The risk is greater with tobacco use. A history of rheumatic fever, heart murmur, or cardiomyopathy is significant for an embolic source. Sudden vision loss without an APD in a diabetic patient is most likely a vitreous hemorrhage. An acquired immunodeficiency syndrome patient with a CD4 count less than 50 × 103 with visual scotomas needs to be evaluated for cytomegalovirus retinitis. A history of alcohol abuse or a psychiatric patient with bilateral vision loss and change in mental status needs urgent chemistries for anion gap acidosis with hemodialysis if methanol ingestion is suspected. An intravenous drug user can suffer a vascular occlusion from talc.
Physical examination
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
Scotoma:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
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: 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
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