Ophthalmology
Jean Edwards
Holt G. Richard Holt
Abnormalities of the ocular structures produce visual dysfunction, altered appearance, pain, or systemic symptoms. Many persons believe vision to be the most important and comprehensive of the senses. Decreased visual acuity can indicate a blinding eye disease that can be controlled with restoration of vision, a systemic disease that can endanger life if not detected and managed, a tumor or other disorder of the central nervous system that can threaten vision and life, or a simple refractive error, correction of which simplifies the patient’s life. Ocular symptoms bring the patient rapidly to the physician because the eyes are the focus of a patient’s perception, and alterations in these structures usually are not ignored.
The otolaryngologist-head and neck surgeon often joins the ophthalmologist in a team approach to care for a patient with congenital or acquired abnormalities of the orbit, adnexa, and periorbital structures. Appreciation of the fundamental concepts of vision, ocular anatomy and physiology, and local and systemic disorders is essential to direct care or assist in caring for a patient with ophthalmic problems (Fig. 14.1). Consultation with an ophthalmologist is mandatory for many disorders and such a joint approach is beneficial to patient care. This chapter highlights the most common disorders seen by otolaryngologist -head and neck surgeons, which have orbital, adnexal, and ocular implications. Also discussed are the best diagnostic studies for the identification of ophthalmologic and orbital disorders, trauma, and tumors.
THE EYE EXAMINATION
The three indications for performing an ocular examination include:
1. Presenting symptoms clearly related to ocular structures, such as pain in the eye and decreased vision
2. Presymptomatic screening to detect controllable eye disease, such as amblyopia and glaucoma
3. Evaluation or diagnosis of systemic disease mirrored in the eye, such as retinopathy and neuropathy in diabetes
With these goals in mind, it is obvious that testing the function of the visual system and examining the eyes should be part of any complete head and neck examination (1).
An eye examination begins with obtaining a history related to the symptoms. Relevant areas are chronology, eye history, family history, concurrent systemic diseases, present use of medications, and existence of allergies. Ocular symptoms usually can be classified into three groups—altered visual function, abnormal sensation, or altered appearance. Abnormalities in visual functioning generally reduce vision, cause superimposed visual phenomena, or produce diplopia. Abnormal sensation in or around the eye can take many forms—deep pain, which signifies intraocular or orbital inflammation; foreign-body pain related to trauma; superficial pain of mild conjunctivitis; vague discomfort known as asthenopia, or eyestrain, with prolonged, intensive use of the eyes; headache related to neurologic disease or tension; or photophobia or ocular pain with exposure to light, most commonly related to corneal abnormalities. Altered appearance usually refers to eyelid abnormalities, orbital deformities, motility disturbances, or redness of the eyeball.
Visual Acuity
An eye examination begins with determining the visual acuity of each eye, with the other eye completely covered. Although measurements are obtained at a distance and near, with and without refraction (glasses), the most important determination of general eye condition is the best-corrected-distance visual acuity, usually assessed with a Snellen chart (which has been in clinical use for 150 years). Examination of children often requires pictures or individual E charts. Each line on the chart is meant to
be read by a person with normal vision at 20 feet (6 m). The largest letter should be seen at 200 feet (60 m) by a person with normal vision. If a patient can see that letter at a distance of 20 feet and is unable to see any of the smaller letters, vision is 20/200. If the line read by a person with normal sight can be seen at 20 feet, and the patient is 20 feet from the chart, the vision is 20/20. If the patient is unable to read the largest letter on the chart, the distance at which he or she can count fingers accurately is recorded. If the patient cannot count fingers, the distance at which hand movements are perceived is determined. If this is not possible, whether the patient can perceive light is documented. Table 14.1 compares visual acuity with visual ability or disability. Vision is not a true fraction. In other words, 20/40 vision does not mean 50% of normal vision but that the patient can see at 20 feet what a person with normal sight can see at 40 feet (12 m). If the patient can see the 20/20 line by wearing glasses, his or her functional vision is probably just as good as that of someone who sees the line without glasses.
be read by a person with normal vision at 20 feet (6 m). The largest letter should be seen at 200 feet (60 m) by a person with normal vision. If a patient can see that letter at a distance of 20 feet and is unable to see any of the smaller letters, vision is 20/200. If the line read by a person with normal sight can be seen at 20 feet, and the patient is 20 feet from the chart, the vision is 20/20. If the patient is unable to read the largest letter on the chart, the distance at which he or she can count fingers accurately is recorded. If the patient cannot count fingers, the distance at which hand movements are perceived is determined. If this is not possible, whether the patient can perceive light is documented. Table 14.1 compares visual acuity with visual ability or disability. Vision is not a true fraction. In other words, 20/40 vision does not mean 50% of normal vision but that the patient can see at 20 feet what a person with normal sight can see at 40 feet (12 m). If the patient can see the 20/20 line by wearing glasses, his or her functional vision is probably just as good as that of someone who sees the line without glasses.
 Figure 14.1 Cross-sectional anatomy of the orbital adnexae and globe: (A) orbicularis oculi muscles, (B) levator aponeurosis, (C) upper tarsal plate, (D) lower tarsal plate, (E) Mueller muscle, (F) orbital septum, and (G) lower eyelid retractors. Courtesy of the American Academy of Otolaryngology-Head and Neck Surgery, Inc. From: Holt JE, Holt GR. Ocular and orbital trauma 1983:10. |
The ophthalmologist uses the process of refraction to determine the refractive error of the eye or the lenses needed for the eye. The need for refraction is determined with a pinhole test. The patient views a chart through a 1-mm pinhole, which reduces the blur of the image on the retina and appreciably increases visual acuity if it is decreased owing to a refractive problem. This test helps to rule out retinal or optic nerve dysfunction as a cause of decreased vision. Measurement of best-corrected visual acuity is an important concept. Often, patients say they are “blind” without their glasses. They should be informed that vision can be physiologically abnormal without pathologic consequence.
Peripheral vision, or side vision, can be evaluated with visual field testing. This test can be performed with various instruments, but it is commonly performed with the confrontation technique. The patient is asked to fix on the examiner’s nose with one eye and to cover the other eye. A test object or finger is brought in from the side until the patient reports it is being seen. The visual field is approximately 90 degrees on the same side but only 50 degrees on the opposite side of testing. Abnormalities of peripheral vision often are detected only through examination because patients report loss of central vision, but loss of peripheral vision is not easily detected. Performing this test for each eye is a good screening method for many neurologic diseases. Ophthalmologists will use a more sophisticated perimeter test to obtain a graphic representation of each visual field to identify and follow visual field defects.
External Inspection and Pupil Examination
Inspection of the external eye structures includes the eyelids, eyelashes, lacrimal apparatus, cornea, conjunctiva and sclera, anterior chamber, and iris, as well as the general symmetry of the face and orbits. Much information can be obtained with this examination, which often reveals the presumptive diagnosis. Particular notice should be taken of abnormal alignment of the eyelids (ptosis or lid retraction), the position of the eyelids against the globe (entropion or ectropion), and abnormal direction of the eyelashes (trichiasis). Swelling in the medial canthal area can indicate a block of proper lacrimal drainage. Proptosis always is an important finding (Fig. 14.2). The causative factor may be orbital, periorbital, or systemic disease. Specific abnormalities in the color and contour of the conjunctiva, cornea, and sclera are discussed later with “red eye.” Of particular importance is an estimation of the depth of the anterior chamber in detecting an important form of glaucoma known as “angle-closure” glaucoma. This test can be performed with side illumination using a penlight. If the anterior chamber is of normal depth, the entire surface of the iris is illuminated. If the anterior chamber is shallow, the iris on the opposite side of the pupil is in shadow.
Examination of the iris usually centers on assessing the pupillary response. When light is shined into the eye, a normal pupil constricts and then redilates after the stimulus is removed. This is the direct light reflex. The opposite pupil constricts as well with the stimulus, and this is known as the consensual light reflex. These reflexes should be brisk and approximately equal. Pupillary constriction is also part of the “near-vision complex” associated with the process of accommodation. If the pupil
reacts to accommodation but not to light, it is the classic Argyll Robertson pupil, often associated with syphilis. A Marcus Gunn pupil is an important physical sign in the evaluation for neurologic disease. It is elicited with the swinging flashlight test. Light is shined in one pupil for 2 or 3 seconds and then rapidly swung back and forth between eyes. Prompt constriction should appear if each pupil is normal. If optic nerve disease or injury is present in the affected eye, the pupil gradually dilates, indicating a decreased direct light reflex. With an impaired neural connection in the affected eye, the examiner will observe a diminished pupillary response in both eyes when the normal eye is stimulated. Thus, the direct response to stimulation of the affected eye and the consensual response in the normal eye are both reduced, compared to the responses when the normal eye is similarly stimulated. Such a reaction usually indicates damage to the optic nerve via the afferent pupillary fibers. This sign is positive early in optic nerve disease, when vision still is 20/30 or better. Abnormal pupillary reaction in any form generally indicates a serious eye disease. For the otolaryngologist, normal visual acuity and normal pupillary responses are comforting findings in evaluating eye problems.
reacts to accommodation but not to light, it is the classic Argyll Robertson pupil, often associated with syphilis. A Marcus Gunn pupil is an important physical sign in the evaluation for neurologic disease. It is elicited with the swinging flashlight test. Light is shined in one pupil for 2 or 3 seconds and then rapidly swung back and forth between eyes. Prompt constriction should appear if each pupil is normal. If optic nerve disease or injury is present in the affected eye, the pupil gradually dilates, indicating a decreased direct light reflex. With an impaired neural connection in the affected eye, the examiner will observe a diminished pupillary response in both eyes when the normal eye is stimulated. Thus, the direct response to stimulation of the affected eye and the consensual response in the normal eye are both reduced, compared to the responses when the normal eye is similarly stimulated. Such a reaction usually indicates damage to the optic nerve via the afferent pupillary fibers. This sign is positive early in optic nerve disease, when vision still is 20/30 or better. Abnormal pupillary reaction in any form generally indicates a serious eye disease. For the otolaryngologist, normal visual acuity and normal pupillary responses are comforting findings in evaluating eye problems.
TABLE 14.1 CORRELATION OF VISUAL IMPAIRMENT WITH VISUAL DISABILITY | ||||||||||||||||||
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 Figure 14.2 Proptosis of the left eye, viewed from anterior (left) and superior (right) positions. |
Motility
Six muscles surrounding each eye are responsible for ocular motility. Several terms are used to describe various eye movements. The movement of one eye from one position to another is called duction. The simultaneous movement of both eyes from the primary, straight-ahead position to a secondary position (up, down, right, left) is called version. Vergence is the term applied to simultaneous rotation of both eyes inward (convergence) or outward (divergence). Evaluation of the extraocular muscle function is begun with general inspection to find any gross deviation of either eye (heterotropia). The patient is asked to look up, down, right, and left to reveal whether the deviation is the same in all fields of gaze (concomitant) or varies (nonconcomitant and usually neurologically significant) (Fig. 14.3). During these gaze movements, involuntary eye jerks, called nystagmus, may also be detected.
The flashlight used to evaluate pupillary reflexes also can be used to assess the corneal light reflex. The light should be symmetrically reflected in each pupil. If deviation is seen, the degree of abnormality can be estimated by the asymmetry of the light reflex in each pupil.
The cover test is used to evaluate motility. The patient is instructed to fix on an object. If both eyes appear straight (orthotropia), cover either one. If under cover the eye deviates, phoria, or latent deviation that becomes evident only when vision is interrupted, has been elicited. Usually, the eye resumes fixation when uncovered. If one eye is obviously deviated, the straight-ahead eye is covered. If the deviated eye rapidly moves to resume fixation, it most likely has good visual potential. The deviation can be eso (inward), exo (outward), hyper (upward), or hypo (downward). Motility disturbances may indicate congenital, neurologic, or metabolic abnormalities.
 Figure 14.3 Heterotropia is characterized by gross asymmetry of eye movement. |
Intraocular Pressure
Measurement of intraocular pressure (IOP) should be performed when assessing orbital trauma or before performing orbital, periorbital, or sinus surgery. The examiner can estimate IOP digitally by placing the tips of the index fingers on the patient’s closed eyelids. All but gross abnormalities remain undetected when this technique is used. A tense globe might be appreciated on palpation as a firmness of the affected globe that is not present with the opposite globe. It is a “soft” sign but, if obvious, is a serious finding. Tonometry is the estimation of IOP with a specialized instrument. It can be performed with an indentation technique or an applanation technique. The former is used in the general screening process and is performed with a Schiotz tonometer. With the patient in a recumbent position, a drop of topical anesthetic is instilled into each eye. The patient is instructed to look straight ahead with both eyes open. Assistance in holding the eyelids open, with pressure on the orbital bones only, not the eye, may be needed. The plunger is gently placed on the center of the patient’s cornea, and the corresponding scale reading is recorded. The test should require only 1 to 2 seconds of contact with the cornea. Normal IOP usually is 15 to 20 mm Hg, with an upper limit of 22 to 23 mm Hg. Both eyes should be tested, in order to obtain baseline levels in the “normal” eye and to compare the pressures between eyes, particularly after facial trauma.
Ophthalmoscopy
The final part of a pertinent eye examination is ophthalmoscopy. It is used to evaluate the internal structures of the eye, primarily the retina, retinal blood vessels, and optic nerve. A direct ophthalmoscope is used for this examination and provides an upright 3× magnified image. Great limitation of the field of view occurs, and the information is obtained as if the examiner is viewing through a small pupil. A 3-mm pupil gives only a 4-degree field of view, but a 7-mm pupil allows a 30-degree field of view. Therefore, routine dilation of the pupils with 0.5% or 1% tropicamide or 2.5% phenylephrine is recommended, with the following exceptions: known narrow-angle glaucoma, neurologic or neurosurgical observation, and some types of intraocular lens implants after cataract surgery. In rare instances, dilation of the pupil can precipitate an attack of acute angle-closure glaucoma that was previously unsuspected. This low risk should not be considered a contraindication to performing the examination. Because this form of glaucoma is rare and can be managed effectively, the benefits of improved ophthalmoscopy through dilated pupils outweigh the risks.
The examiner holds the ophthalmoscope in the right hand and uses the right eye to examine the patient’s right eye. With the pupil dilated, reflected light from the ocular fundus produces a clear red reflex when viewed through
the ophthalmoscope with a 16 diopter lens at a distance of approximately 1 foot (0.3 m). Any alteration in the red reflex indicates abnormality in one of the optical structures of the eye and is always important. The patient’s eye is then approached as closely as possible as the power of the lens in the ophthalmoscope is reduced until the optic disk comes into focus. The nerve head, at the back of the eye, should be evaluated for color, sharpness of margins, and appearance of the central depressed area, known as the cup. Systematic examination of the retinal vessels and background then is performed. The macular region deserves special attention for patients with vision loss. This examination is performed on both eyes.
the ophthalmoscope with a 16 diopter lens at a distance of approximately 1 foot (0.3 m). Any alteration in the red reflex indicates abnormality in one of the optical structures of the eye and is always important. The patient’s eye is then approached as closely as possible as the power of the lens in the ophthalmoscope is reduced until the optic disk comes into focus. The nerve head, at the back of the eye, should be evaluated for color, sharpness of margins, and appearance of the central depressed area, known as the cup. Systematic examination of the retinal vessels and background then is performed. The macular region deserves special attention for patients with vision loss. This examination is performed on both eyes.
Schirmer Testing
The Schirmer test is only a general qualitative screening test for tear production. It is often equivocal and only a glimpse of the tear production at the time of the test. Hydration status and environmental factors can change tear production even within a day’s time. There are three components to the Schirmer testing, all three of which should be performed to gain as much information as possible.
The Schirmer I test can be performed with or without topical anesthesia (2). For all tests, the lower cul-de-sac is wiped clean of retained tears, gently, with a cotton-tipped applicator. For the unanesthetized test, the filter paper strip (Whatman filter paper no. 41) is notched and placed in the lower eyelid cul-de-sac and left in place for 5 minutes— the patient eyes can be open or closed. This test measures both basic tear production by the accessory tear glands as well as the reflex tearing from the lacrimal gland produced in response to the foreign body on the conjunctiva of the eyelid. A “wetting” of the paper of 10 mm or greater is considered “normal.” The second part of the test is to apply two drops of 0.5% ophthalmic tetracaine solution to the inferior cul-de-sac, which eliminates the reflexive tear production by the lacrimal gland and measures the basic tear secretion by the accessory glands (i.e., meibomian glands). The test is then conducted similarly to the unanesthetized version. A paper “wetting” of less than 5 mm is considered abnormal. The third portion of the test is the Schirmer II test, which can be performed with the eyelid either anesthetized or unanesthetized. In this test, the ipsilateral nostril is stimulated with cotton from a cotton-tipped applicator to stimulate a neural reflex for tear production, similar to that which occurs naturally when a foreign body is inhaled into the nose. Any “wetting” under 15 mm is likely abnormal.
Quite a number of etiologies can explain inadequate tear production, including facial nerve dysfunction, advancing age, postmenopause, Sjogren disease and other autoimmune diseases, dehydration, and medications (antihypertensives, diuretics, birth control pills, psychotropics), just to name a few. The importance of Schirmer testing in otolaryngology -head and neck surgery is primarily in the preoperative assessment for eyelid surgery and in the diagnosis of autoimmune disorders affecting the head and neck region.
VISUAL ABNORMALITIES
Physiologically Decreased Vision
Refractive Error
A common cause of poor vision is refractive error or change in refractive error. Patients with myopia (nearsightedness) have an eye that is axially too long for its refractive system. Typically a young patient reports not being able to see the blackboard and having to sit at the front of the classroom. Simple prescription of concave lenses usually restores visual acuity to normal. Persons with hyperopia, or farsightedness, have an eye that is axially too short and need simple convex lenses to bring near objects into focus. Aphakia is a special form of hyperopia in which the refractive power of the eye is too weak following surgical removal of the lens. Astigmatism is the nonspheric curvature of the cornea and is extremely common with any refractive error.
Refractive visual surgery, in the form of LASIK (laserassisted in situ keratomileusis) or PRK (photorefractive keratectomy), is becoming increasingly common among patients with myopia. Patients seeking elective reduction of physiologic myopia elect these procedures, which reshape the cornea to improve its curvature. New technology can produce a detailed topographic “map” of the corneal surface, which drives the reshaping process very precisely. These advances have reduced complications and produced more consistent results, including a decreased trend toward a hyperopic drift with time. Some patients need additional mild corrections after the primary surgery, called enhancements, to complete the visual improvement process. Side effects of corneal reshaping surgery include halo effect, double vision (“ghosting”), loss of contrast sensitivity, and glare.
Presbyopia
Presbyopia is the term used to describe the clinical need for reading glasses or bifocals as the patient enters the fourth and fifth decades of life. The crystalline lens hardens with age and becomes less elastic, decreasing ability to accommodate or focus for near vision. This is a normal physiologic mechanism and should not be considered a sign of disease. When a cataract forms and interferes with functional vision, it can be removed and replaced with a synthetic, polymer lens specific to the patient’s vision system.
Pathologically Decreased Vision
Gradual Loss of Vision
In evaluating reduced vision in pathologic terms, best-corrected visual acuity must first be achieved to eliminate the physiologic abnormalities. The three most common causes of gradual loss of vision are cataract, senile macular degeneration, and glaucoma.
Cataract formation, the loss of transparency of the crystalline lens, is common. Increased density of the lens fibers
and changes in protein content occur, almost without exception, to some degree in every person with increasing age; however, the loss of transparency can be so marked that visual function is seriously hampered. The term cataract usually is reserved for the latter situation. Cataract formation usually is evolutional, but it occasionally has a specific cause, such as galactosemia, galactokinase deficiency, diabetic ketoacidosis, postradiation therapy, or trauma. If a metabolic abnormality can be corrected early in the course of cataract formation, some lens opacity can be reversed; however, there is no known reversal of lens changes due to senile cataract. Treatment is surgical removal of the cataract. The need for surgery usually depends on the patient’s visual requirements and desires. In rare instances, the cataract damages the eye because of high pressure from rapid swelling and may have to be removed for other than optical reasons.
and changes in protein content occur, almost without exception, to some degree in every person with increasing age; however, the loss of transparency can be so marked that visual function is seriously hampered. The term cataract usually is reserved for the latter situation. Cataract formation usually is evolutional, but it occasionally has a specific cause, such as galactosemia, galactokinase deficiency, diabetic ketoacidosis, postradiation therapy, or trauma. If a metabolic abnormality can be corrected early in the course of cataract formation, some lens opacity can be reversed; however, there is no known reversal of lens changes due to senile cataract. Treatment is surgical removal of the cataract. The need for surgery usually depends on the patient’s visual requirements and desires. In rare instances, the cataract damages the eye because of high pressure from rapid swelling and may have to be removed for other than optical reasons.
The operation usually is performed by means of opening the anterior capsule and extracting the lens material. The posterior capsule is left intact and the lens substance removed by phacoemulsification. After a person is aphakic, the optical power of the lens must be replaced to provide focusing ability. The patient can be fitted with spectacles or contact lenses after the eye has healed, but usually, a polymer intraocular lens is implanted during the surgical procedure, with the appropriate lens strength being determined preoperatively. It is comforting to inform patients that cataract surgery is one of the most successful operations performed.
A second important cause of gradual progressive decrease in vision among older persons is senile macular degeneration. The cause of this condition is unknown, but it may be related to a decrease in the blood supply to the macular area associated with hardening of the arteries in the posterior eye, which begins as a pigmentary disturbance in the macula and usually progresses slowly but steadily with increased scarring and often hemorrhage into the tissues. The disease is bilateral but usually asymmetrical. No effective treatment exists, and normal use of the eyes, as for sewing and reading, does not accelerate the process. Patients should be assured that macular degeneration is not a blinding disease because the peripheral vision is not disturbed. Patients with this condition always are able to move around unaided, even though their useful reading vision may be markedly decreased.
Unlike the two aforementioned visually disabling conditions, glaucoma characteristically produces a decrease in peripheral visual ability, but good reading vision is maintained until late in the disease. Mild glaucoma can normally be controlled with daily topical eye drops.
Sudden Loss of Vision
Sudden loss of vision is a dramatic event and usually is caused by an identifiable pathologic process. Some processes can be treated and controlled to allow restoration of vision, while others produce permanent loss of visual function. Vitreous hemorrhage unrelated to trauma can occur in advanced diabetes mellitus as a result of disease of the retinal blood vessels. The vitreous “haze” prevents complete examination of the retinal blood vessels, and the offending area often remains unidentified until the blood is reabsorbed. It can take months or years for the vitreous to clear in a relatively young person, producing marked disability, while it may never clear in an older person.
Central retinal arterial occlusion causes total and permanent loss of vision and abolishment of the direct pupillary reaction to light. On ophthalmoscopic examination, the fundus will appear pale with development of a cherryred spot in the macula. The spot is caused by continued choroidal blood supply to the macula with the contrasting loss of circulation to the rest of the retina. The retinal arteries are narrow and may have fragmented blood columns (“boxcar sign”). The cause usually is an embolus from diseased carotid arteries, abnormal heart valves, or thrombosis from long-standing atherosclerosis. In rare instances, central retinal arterial occlusion is a vasospastic event associated with an inflammatory disease. Treatment aimed at relieving the obstruction through drug-induced vasodilation, ocular massage, and inhalation of 5% carbon dioxide and 95% oxygen usually is unsuccessful. Attacks of amaurosis fugax and central or branch retinal artery occlusion have been shown to be related to internal carotid artery stenosis (3). An increase in ulcerated free plaque surfaces appears, which might lead to arterial embolization. Duplex ultrasonography and continuous-wave Doppler ultrasonography can be used for obtaining a noninvasive diagnosis; however, magnetic resonance angiography (MRA) is rapidly gaining favor as a sensitive screening test for carotid stenosis.
Central retinal venous occlusion is more common and less dramatic than arterial occlusion, and it has a markedly better prognosis. On ophthalmoscopic examination, the fundus has a dramatic appearance, as if the entire view has been splattered with blood, and the observed vessels appear engorged and tortuous. Much of the hemorrhage clears with time, vision returns, and late complications of retinal anoxia are managed by the ophthalmologist.
Retinal detachment is not a rare occurrence. It is much more common among persons with high myopia (those with long eyeballs), after cataract surgery (˜1 in 100), and following facial trauma. The mode of visual loss varies. The patient commonly reports a shadow or curtain in front of the eye, ascending or descending, depending on the direction of the spreading separation of the retina. Associated flashing lights and floaters may be seen as the retinal structure is disturbed. If the macula becomes detached, central vision is abruptly lost. At ophthalmoscopy, the detached retina is found to be pale and wrinkled and to project forward into the vitreous, often to the point at which objects viewed cannot be focused by the lens onto the retina. Surgical reattachment of the retina is successful in 60% to 80% of cases, but return of vision depends on early
diagnosis, length of time detached, and avoidance of late surgical complications.
diagnosis, length of time detached, and avoidance of late surgical complications.
 Figure 14.4 Edema of the optic disk indicates optic neuritis. |
Optic nerve compromise, whether in the form of ischemia or inflammation, is not as common as retinal detachment, but it is equally dramatic and important. A patient older than 55 years who has sudden loss of vision and perhaps has vague arthritic symptoms, low-grade fever, or temporal scalp tenderness should have the erythrocyte sedimentation rate (ESR) measured. If the ESR is elevated, the diagnosis is most likely temporal arteritis, with the opposite eye being at risk for parallel visual loss. Systemic steroid therapy should be initiated early to prevent the onset of inflammation in the other eye. For a younger person, if loss of vision is associated with edema of the optic disk, the diagnosis is likely optic neuritis (Fig. 14.4). The prognosis for return of vision is good, but the possibility that a demyelinating disorder, such as multiple sclerosis, is present must be strongly considered.
Sometimes, the report of sudden loss of vision is unfounded. This usually occurs when an older patient suddenly “discovers” a loss of sight that has existed for some time. Chance occlusion of the seeing eye reveals the visual loss, which is erroneously reported as being acute. The report of sudden loss of vision also can be associated with hysteria or malingering and the desire for secondary gain. This is especially true in young adolescents.
Transient Loss of Vision
Transient loss of vision can be part of the aura of migraine or a consequence of chronic papilledema. Visual blackouts are common in vertebral-basilar insufficiency after at least 80% narrowing of this vascular system from atherosclerosis. These blackouts are ominous because repeated attacks often are not transient and can be permanent. Abnormalities in the carotid system can cause temporary, usually unilateral, loss of vision (amaurosis fugax). Associated cerebral symptoms and hemiparesis may be noted. Because 15% to 20% of these patients later have a stroke, they need a complete vascular evaluation.
Diplopia
Diplopia is another symptom of visual abnormality. Physiologic diplopia is a normal phenomenon in which objects not within the area of fixation are seen as double. This is easily seen when one looks at a near object with attention directed at a distant object, which then appears double. Usually, this is not in one’s conscious awareness. Diplopia can either be monocular or binocular, and this must be determined initially through eye cover testing (4). Pathologic diplopia is a cardinal sign of weakness of one or more of the extraocular muscles and usually is caused by neurologic disease, trauma, or diabetes mellitus. Diplopia also can occur with normal muscle function if the globe is displaced, as in slowly progressive e orbital disease or tumors that prevent proper alignment of visual stimuli. Monocular diplopia (that which does not go away when one eye is covered) is rare and usually due to splitting of light rays by an irregularity in the cornea, certain types of cataracts, or misaligned photoreceptors in the macula. More commonly, monocular diplopia is a neurotic or functional disorder.
RED EYE
The otolaryngologist-head and neck surgeon occasionally encounters a patient with a red eye
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