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Ischemic Optic Neuropathy
Neuro-ophthalmologic Problems
Ischemic Optic Neuropathy Still the Ophthalmologist's Dilemma W. THOMAS SHULTS, MD
Abstract: Ischemic optic neuropathy, in its arteritic and idiopathic varieties, presents both diagnostic and therapeutic challenges to the clinician, specificially: the role of temporal artery biopsy in management of giant cell arteritis; the preferred treatment regimen for giant cell arteritis, including decisions to begin tapering therapy and stopping therapy; action to take if major steroid complications arise while the disease is still active; distinguishing anterior ischemic optic neuropathy from idiopathic optic neuritis; whether cerebral arteriography is indicated in the assessment of idiopathic ischemic optic neuropathy; and whether steroid therapy is of any value in the treatment of idiopathic ischemic optic neuropathy. [Key words: carotid artery, corticosteroids, cranial arteritis, disc edema, giant cell arteritis, ischemic optic neuropathy, optic neuritis, temporal arteritis.] Ophthalmology 91:1338-1341, 1984
Anterior ischemic optic neuropathy is the most common cause of optic disc edema in patients over the age 55 years. 1 This entity, which results from interruption of blood flow to the optic nerve head, has only been recognized in the American literature as a cause of optic disc swelling since 1966, when Miller and Smith2 properly ascribed the clinical picture to a vascular occlusive process. Though most often idiopathic, anterior ischemic optic neuropathy can complicate a large number of systemic diseases. Thus vasculitides, such as polyarteritis nodosa and allergic vasculitis, vasculopathies, such as hypertension and atherosclerosis, hematologic disorders, such as polycythemia, and even surgical causes such as cataract extraction have been implicated in causing ischemic optic neuropathy.
ARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY Among the identified causes, giant cell arteritis is the entity of greatest ophthalmic interest and poses several From the Good Samaritan Hospital and Medical Center and Oregon Health Sciences University, Portland, Oregon. Presented at the Eighty-eighth Annual Meeting of the American Academy of Ophthalmology, Chicago, Illinois, October 30-November 3, 1983. Reprint requests toW. Thomas Shults, MD, 2282 N.W. Northrup, #33, Portland, OR 97210.
1338
diagnostic and therapeutic dilemmas. This disorder, a multisymptomatic disease of the elderly, is characterized by malaise, anorexia, weight loss, anemia, temporal artery tenderness, polymyalgia rheumatica, jaw claudication and low grade fever. Over one-third of patients will develop severe vision loss if untreated. 3 Visual loss may be total, involve the central area only, or be sectoral or altitudinal in nature. About 25% of untreated patients will lose vision comp~etely. 3 Vision loss in giant cell arteritis tends to be more severe than that seen in nonarteritic ischemic optic neuropathy. Anterior ischemic optic neuropathy is the most frequent cause of visual loss in giant cell arteritis and is believed to result from occlusion of the short posterior ciliary arteries with consequent disc infarction. Pallid disc edema and flame-shaped peripapillary hemorrhages are the most common feature of the clinical appearance of the fundus of the patient with arteritic anterior ischemic optic neuropathy though some patients may have cotton wool spots, choroidal infarcts, or central retinal artery occlusions. On occasion, the fundus is normal, suggesting retrobulbar ischemic neuropathy. 4 Not uncommonly, transient visual loss may precede the final blinding event by hours or days, an association which should prompt concern when amaurosis fugax occurs in an elderly patient. A substantial number of elderly patients with anterior ischemic optic neuropathy, but without classical symptoms of giant cell arteritis, will be found to have an occult form of this disease with an elevated sedimentation rate and a positive
SHULTS
•
ISCHEMIC OPTIC NEUROPATHY
temporal artery biopsy. 5 These latter two tests play a central role in confirming the diagnosis of giant cell arteritis. Most patients with this disease have a markedly elevated (above 100 mm/hr) Westergren sedimentation rate (using 40 mm/hr as the upper limit of normal in the over-65-year-old age group affected), though the absence of such does not rule out the diagnosis. 6 Similarly, most patients with giant cell arteritis will have a positive temporal artery biopsy, but in some this test will prove negative, possibly because of inadvertent sampling of a skip area (known to. occur in about 25% of affected patients7 ). Thus, the 70-year-old patient with anterior ischemic optic neuropathy who is devoid of symptoms of giant cell arteritis and has a Westergren sedimentation rate of 50 presents a difficult problem for the clinician. What is the role of temporal artery biopsy in the diagnosis of such a patient? Does one biopsy the opposite side if the first biopsy is negative? Is frozen section analysis of the biopsy adequate to derive conclusions as to its positivity or negativity? If both sides prove negative, how do you treat the patient? Corticosteroids are of unequivocal benefit in the management of this condition, and general agreement exists that steroids should be started as soon as the diagnosis is suspected, without waiting for biopsy confirmation. Less settled is the proper treatment regimen, 6 ie. how much steroid and for how long, and the criteria used for tapering and discontinuing therapy. Is there a minimum treatment period during which therapy should be continued despite lack of symptoms and a normal sedimentation rate? What action should the ophthalmologist take if that patient develops major complications of steroid therapy (spinal compression fractures and peptic ulcer disease) but shows an increasing sedimentation rate when steroids are tapered?
NONARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY Though sometimes associated with systemic diseases such as giant cell arteritis, anterior ischemic optic neuropathy more often occurs as an isolated event in an otherwise healthy patient, or one who at most has hypertension as his or her only sign of systemic disease. Vision loss in such patients is usually abrupt, painless, occurs without premonitory symptoms and is associated with disc edema, peripapillary hemorrhages and discrelated visual field defects. While the occasional younger patient with diabetes or migraine may develop anterior ischemic optic neuropathy, the usual patient is between the ages of 45 and 65 years. Though vision loss in idiopathic anterior ischemic optic neuropathy can be quite severe, it is generally less extensive than that seen in giant cell arteritis. Not all patients will develop loss of central vision, however. With segmental disc infarction, patients may develop arcuate, wedge-shaped or altitudinal field cuts with fixation being spared. Occa-
sional patients develop papillomacular bundle infarctions with resultant central scotomas. Disc swelling in idiopathic anterior ischemic optic neuropathy can be diffuse or sectoral and may be pallid or hyperemic. Of great importance is the high incidence of other eye involvement in this disease. Approximately 40% of patients develop vision loss in the opposite eye days, weeks, months, or years after the onset of symptoms in one eye. Many features of this condition mimic those seen in inflammatory papillitis. When a 50-year-old non-hypertensive, non-diabetic man without evidence of systemic vasculitidy presents with a swollen, hyperemic optic neuropathy with peripapillary hemorrhages, altitudinal field loss, and no history of ocular pain, how does one distinguish between idiopathic ischemic optic neuropathy and idiopathic optic neuritis? Given the age group in which it occurs and the increased incidence in diabetics and hypertensives, idiopathic ischemic optic neuropathy is most often ascribed to atherosclerotic involvement of the posterior ciliary vessels. As this disease is nonfatal, pathologic material is difficult to obtain. However, Lieberman et al9 have reported the histopathologic changes in a single patient in whom vascular compromise in anterior optic nerve vessels resulted from embolic occlusion, presumably from a carotid source. In view of this finding, is it reasonable to treat anterior idiopathic ischemic optic neuropathy as a sign of carotid occlusive disease? Should such patients be subjected to carotid angiography or noninvasive carotid flow testing? Perhaps the most thorny issue surrounding the management of idiopathic anterior ischemic optic neuropathy is the place of systemic corticosteroids. While it is widely agreed that high dose corticosteroid therapy is indicated in the treatment of the patients with arteritic ischemic optic neuropathy, there is little unanimity of opinion regarding their use in the idiopathic form of this disorder. Boghen and GlaserB concluded that steroids were of no value, while Hayreh et al, 10 Foulds, ll and Eagling et al 12 derived the opposite conclusion. What role, if any, is there for the use of corticosteroids in the management of idiopathic ischemic optic neuropathy?
SUMMARY Anterior ischemic optic neuropathy, in both its arteritic and idiopathic forms, confronts the clinician with several difficult problems: What is the role of temporal artery biopsy in the systemically asymptomatic elderly patient with ischemic optic neuropathy and borderline sedimentation rate? If biopsy is necessary, does the clinician perform one on the opposite side if the first side is negative? If both sides prove negative, how would one treat the patient? If the patient had classical symptoms but a normal sedimentation rate and negative biopsies bilaterally, 1339
OPHTHALMOLOGY •
NOVEMBER 1984 •
would one still treat the patient if vision loss had not occurred? What is the preferred treatment regimen for giant cell arteritis? How does one decide when to decrease therapy? To stop therapy? If major steroid complications intervene, but the disease is still active (sedimentation rate elevated), what should be done? How does one distinguish idiopathic ischemic optic neuropathy from idiopathic optic neuritis? Is arteriography or noninvasive carotid flow testing indicated in the assessment of the typical patient with idiopathic anterior ischemic optic neuropathy? What role, if any, should corticosteroids play in the management of idiopathic ischemic optic neuropathy?
REFERENCES 1. Miller NR. Anterior ischemic optic neuropathy: diagnosis and management. Bull NY Acad Med 1980; 56:643-54. 2. Miller GR, Smith JL. Ischemic optic neuropathy. Am J Ophthalmol 1966; 62:103-15.
VOLUME 91
•
NUMBER 11
3. Keltner JL. Giant-cell arteritis; signs and symptoms. Ophthalmology 1982; 89:1101-10. 4. Hayreh SS. Posterior ischemic optic neuropathy. Ophthalmologica 1981; 182:29-41. 5. Simmons RJ, Cogan DG. Occult temporal arteritis. Arch Ophthalmol 1962; 68:8-18. 6. Eshaghian J. Controversies regarding giant cell (temporal, cranial) arteritis. Doc Ophthalmol1979; 47:43-67. 7. Klein RG, Campbell RJ, Hunder GG, Carney JA. Skip lesions in temporal arteritis. Mayo Clin Proc 1976; 51:504-10. 8. Boghen DR, Glaser JS. lschaemic optic neuropathy; the clinical profile and history. Brain 1975; 98:689-708. 9. Lieberman MF, Shahi A, Green WR. Embolic ischemic optic neuropathy. Am J Ophthalmol1978; 86:206-10. 10. Hayreh SS. Anterior ischaemic optic neuropathy. Ill. Treatment, prophylaxis, and differential diagnosis. Br J Ophthalmol 1974; 58: 981-9. 11 . Foulds WS. Visual disturbances in systemic disorders: optic neuropathy and systemic disease. Trans Ophthalmol Soc UK 1969; 89:125-46. 12. Eagling EM, Sanders MD, Miller SJH. lschaemic papillopathy; clinical and fluorescein angiographic review of forty cases. Br J Ophthalmol 1974; 58:990-1008.
Discussion by Joel S. Glaser, MD, RobertS. Hepler, MD, Neil R. Miller, MD, H. Stanley Thompson, MD The panel considered Dr. Shults' questions individually: Temporal artery biopsy. A temporal artery biopsy should be done when the diagnosis is clinically suspected. Not only to confirm the diagnosis but also to support the use of steroids when, nine months later, someone reviews the case and says "Why have you got this lady on prednisone?" The initial decision to treat is usually made on the basis of history, the ocular findings, and an elevated erythrocyte sedimentation rate. If both temporal arteries are biopsied, one after the other, and both are read as negative, then the steroids would be slowly discontinued with an eye on the sedimentation rate and on other possible reasons for its elevation. Treatment of temporal arteritis. Temporal arteritis is treated with large doses of prednisone in order to prevent further visual loss. The usual starting dose is about I00 mg/day and the do~e is often kept over 40 mg/day for a month. The prednisone should be tapered slowly with a view of keeping the sedimentation rate low with a minimum amount of medication. Expect to continue this treatment for many months, sometimes for years. Unfortunately, in the event of steroid complications, no acceptable alternative treatment is available. Ischemic optic neuropathy versus optic neuritis. Usually there is little difficulty distinguishing anterior ischemic optic neuropathy from optic neuritis. Anterior ischemic optic neuropathy occurs in both sexes and is most common over the age of 50, whereas optic neuritis is more common in women, and under the age of 40. The field loss is quite different in the two conditions: in anterior ischemic optic neuropathy altitudinal
From the University of Iowa, Iowa City, Iowa.
1340
or disk-related field loss is the rule, although central visual loss occurs in perhaps one-third of the cases, whereas in optic neuritis a central scotoma is the rule at first but this soon clears up leaving patchy shallow paracentral defects that are hard to plot. Arcuate defects (disk-related) can occur in optic neuritis. The onset of the visual loss can be similar in the two conditions: In anterior ischemic optic neuropathy it may come on overnight, and in the next few days it may worsen. Generally, there is no pain. In optic neuritis, the visual deficit is often preceded by pain on eye movement, and the visual loss may gradually worsen for two to five days. The fundus appearance is quite different in the two conditions: In anterior ischemic optic neuropathy there is often regional swelling of the disk with striate hemorrhages, and in severe cases, a deep pallor. In optic neuritis the disk is usually normal, but in some cases there is a mild, diffuse disk swelling (papillitis). A pupil defect is visible in both conditions. In anterior ischemic optic neuropathy the size of the relative afferent pupil defect matches the field lost, but in optic neuritis the pupil defect may seem to exceed the field loss if you use kinetic perimetry. In summary, there is usually no difficulty in making the right diagnosis, but there is an area of overlap between the two conditions: if one sees a 45-year-old woman with painless arcuate field loss and a mildly swollen disk, it may be necessary to repeat the history of the onset, perform a neurological examination, and a visual evoked potential in each eye; even then the diagnosis may not be absolutely clear. Arteriography. This is not indicated in the assessment of a typical patient with idiopathic anterior ischemic optic neuropathy.
SHULTS
•
ISCHEMIC OPTIC NEUROPATHY
Steroid treatment for ischemic optic neuropathy. I think we are all in agreement that when part of the optic nerve head is completely infarcted, it is permanently infarcted and no amount of steroids will restore it to normal function. If this were the only kind of anterior ischemic optic neuropathy, then indeed there would be no place for steroids in its management. But some patients with anterior ischemic optic neuropathies lose more field after the first altitudinal field loss, while some improve. The defect is not always permanent and stable. Furthermore, it seems that an optic disk can suffer a hypoxic swelling without field loss. The swelling itself may contribute to fiber damage at the disk and thus produce loss of visual field. In this situation, reduction of the swelling by a short course of systemic steroids might be expected to be of some help. In giant cell arteritis there is a severe disk infarction which, as a rule, does not improve with steroids; nor does a massive nonarteritic infarction with pallid disk swelling. It seems reasonable to assume that in these cases there has actually been an occlusion of a posterior ciliary artery. It isn't necessary for a vessel to become actually occluded to cause hypoxic damage; a temporary drop in perfusion pressure is all that is
required. This may be why many patients awaken with an ischemic optic neuropathy. If the blood pressure drops a few points during the night and the intraocular pressure goes up transiently as the patient rests an eye on a pillow, this may impair perfusion enough to cause a hypoxic swelling of the disk and thus a disk-related field loss. If some of this field loss is potentially reversible, then I believe that a course of steroids is worth trying, though it seems most of my colleagues on this panel disagree. We use 80 to 100 mg prednisone for two weeks, and if the field loss does not improve we taper the dosage during the following two weeks. In general, we try to keep the dose at at least 40 mg/day as long as the disk is swollen. Most patients receive three to six weeks of tapering steroids. We have not been troubled with drug-induced complications, and a sizeable percentage of our patients have shown improvement of their visual field loss. Of course, it still has not been proven that the steroids are doing more good than harm. The only way to settle this is with a carefully designed therapeutic trial which is difficult and expensive to arrange. H. STANLEY THOMPSON, MD
1341
Ischemic Optic Neuropathy Still the Ophthalmologist's Dilemma W. THOMAS SHULTS, MD
Abstract: Ischemic optic neuropathy, in its arteritic and idiopathic varieties, presents both diagnostic and therapeutic challenges to the clinician, specificially: the role of temporal artery biopsy in management of giant cell arteritis; the preferred treatment regimen for giant cell arteritis, including decisions to begin tapering therapy and stopping therapy; action to take if major steroid complications arise while the disease is still active; distinguishing anterior ischemic optic neuropathy from idiopathic optic neuritis; whether cerebral arteriography is indicated in the assessment of idiopathic ischemic optic neuropathy; and whether steroid therapy is of any value in the treatment of idiopathic ischemic optic neuropathy. [Key words: carotid artery, corticosteroids, cranial arteritis, disc edema, giant cell arteritis, ischemic optic neuropathy, optic neuritis, temporal arteritis.] Ophthalmology 91:1338-1341, 1984
Anterior ischemic optic neuropathy is the most common cause of optic disc edema in patients over the age 55 years. 1 This entity, which results from interruption of blood flow to the optic nerve head, has only been recognized in the American literature as a cause of optic disc swelling since 1966, when Miller and Smith2 properly ascribed the clinical picture to a vascular occlusive process. Though most often idiopathic, anterior ischemic optic neuropathy can complicate a large number of systemic diseases. Thus vasculitides, such as polyarteritis nodosa and allergic vasculitis, vasculopathies, such as hypertension and atherosclerosis, hematologic disorders, such as polycythemia, and even surgical causes such as cataract extraction have been implicated in causing ischemic optic neuropathy.
ARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY Among the identified causes, giant cell arteritis is the entity of greatest ophthalmic interest and poses several From the Good Samaritan Hospital and Medical Center and Oregon Health Sciences University, Portland, Oregon. Presented at the Eighty-eighth Annual Meeting of the American Academy of Ophthalmology, Chicago, Illinois, October 30-November 3, 1983. Reprint requests toW. Thomas Shults, MD, 2282 N.W. Northrup, #33, Portland, OR 97210.
1338
diagnostic and therapeutic dilemmas. This disorder, a multisymptomatic disease of the elderly, is characterized by malaise, anorexia, weight loss, anemia, temporal artery tenderness, polymyalgia rheumatica, jaw claudication and low grade fever. Over one-third of patients will develop severe vision loss if untreated. 3 Visual loss may be total, involve the central area only, or be sectoral or altitudinal in nature. About 25% of untreated patients will lose vision comp~etely. 3 Vision loss in giant cell arteritis tends to be more severe than that seen in nonarteritic ischemic optic neuropathy. Anterior ischemic optic neuropathy is the most frequent cause of visual loss in giant cell arteritis and is believed to result from occlusion of the short posterior ciliary arteries with consequent disc infarction. Pallid disc edema and flame-shaped peripapillary hemorrhages are the most common feature of the clinical appearance of the fundus of the patient with arteritic anterior ischemic optic neuropathy though some patients may have cotton wool spots, choroidal infarcts, or central retinal artery occlusions. On occasion, the fundus is normal, suggesting retrobulbar ischemic neuropathy. 4 Not uncommonly, transient visual loss may precede the final blinding event by hours or days, an association which should prompt concern when amaurosis fugax occurs in an elderly patient. A substantial number of elderly patients with anterior ischemic optic neuropathy, but without classical symptoms of giant cell arteritis, will be found to have an occult form of this disease with an elevated sedimentation rate and a positive
SHULTS
•
ISCHEMIC OPTIC NEUROPATHY
temporal artery biopsy. 5 These latter two tests play a central role in confirming the diagnosis of giant cell arteritis. Most patients with this disease have a markedly elevated (above 100 mm/hr) Westergren sedimentation rate (using 40 mm/hr as the upper limit of normal in the over-65-year-old age group affected), though the absence of such does not rule out the diagnosis. 6 Similarly, most patients with giant cell arteritis will have a positive temporal artery biopsy, but in some this test will prove negative, possibly because of inadvertent sampling of a skip area (known to. occur in about 25% of affected patients7 ). Thus, the 70-year-old patient with anterior ischemic optic neuropathy who is devoid of symptoms of giant cell arteritis and has a Westergren sedimentation rate of 50 presents a difficult problem for the clinician. What is the role of temporal artery biopsy in the diagnosis of such a patient? Does one biopsy the opposite side if the first biopsy is negative? Is frozen section analysis of the biopsy adequate to derive conclusions as to its positivity or negativity? If both sides prove negative, how do you treat the patient? Corticosteroids are of unequivocal benefit in the management of this condition, and general agreement exists that steroids should be started as soon as the diagnosis is suspected, without waiting for biopsy confirmation. Less settled is the proper treatment regimen, 6 ie. how much steroid and for how long, and the criteria used for tapering and discontinuing therapy. Is there a minimum treatment period during which therapy should be continued despite lack of symptoms and a normal sedimentation rate? What action should the ophthalmologist take if that patient develops major complications of steroid therapy (spinal compression fractures and peptic ulcer disease) but shows an increasing sedimentation rate when steroids are tapered?
NONARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY Though sometimes associated with systemic diseases such as giant cell arteritis, anterior ischemic optic neuropathy more often occurs as an isolated event in an otherwise healthy patient, or one who at most has hypertension as his or her only sign of systemic disease. Vision loss in such patients is usually abrupt, painless, occurs without premonitory symptoms and is associated with disc edema, peripapillary hemorrhages and discrelated visual field defects. While the occasional younger patient with diabetes or migraine may develop anterior ischemic optic neuropathy, the usual patient is between the ages of 45 and 65 years. Though vision loss in idiopathic anterior ischemic optic neuropathy can be quite severe, it is generally less extensive than that seen in giant cell arteritis. Not all patients will develop loss of central vision, however. With segmental disc infarction, patients may develop arcuate, wedge-shaped or altitudinal field cuts with fixation being spared. Occa-
sional patients develop papillomacular bundle infarctions with resultant central scotomas. Disc swelling in idiopathic anterior ischemic optic neuropathy can be diffuse or sectoral and may be pallid or hyperemic. Of great importance is the high incidence of other eye involvement in this disease. Approximately 40% of patients develop vision loss in the opposite eye days, weeks, months, or years after the onset of symptoms in one eye. Many features of this condition mimic those seen in inflammatory papillitis. When a 50-year-old non-hypertensive, non-diabetic man without evidence of systemic vasculitidy presents with a swollen, hyperemic optic neuropathy with peripapillary hemorrhages, altitudinal field loss, and no history of ocular pain, how does one distinguish between idiopathic ischemic optic neuropathy and idiopathic optic neuritis? Given the age group in which it occurs and the increased incidence in diabetics and hypertensives, idiopathic ischemic optic neuropathy is most often ascribed to atherosclerotic involvement of the posterior ciliary vessels. As this disease is nonfatal, pathologic material is difficult to obtain. However, Lieberman et al9 have reported the histopathologic changes in a single patient in whom vascular compromise in anterior optic nerve vessels resulted from embolic occlusion, presumably from a carotid source. In view of this finding, is it reasonable to treat anterior idiopathic ischemic optic neuropathy as a sign of carotid occlusive disease? Should such patients be subjected to carotid angiography or noninvasive carotid flow testing? Perhaps the most thorny issue surrounding the management of idiopathic anterior ischemic optic neuropathy is the place of systemic corticosteroids. While it is widely agreed that high dose corticosteroid therapy is indicated in the treatment of the patients with arteritic ischemic optic neuropathy, there is little unanimity of opinion regarding their use in the idiopathic form of this disorder. Boghen and GlaserB concluded that steroids were of no value, while Hayreh et al, 10 Foulds, ll and Eagling et al 12 derived the opposite conclusion. What role, if any, is there for the use of corticosteroids in the management of idiopathic ischemic optic neuropathy?
SUMMARY Anterior ischemic optic neuropathy, in both its arteritic and idiopathic forms, confronts the clinician with several difficult problems: What is the role of temporal artery biopsy in the systemically asymptomatic elderly patient with ischemic optic neuropathy and borderline sedimentation rate? If biopsy is necessary, does the clinician perform one on the opposite side if the first side is negative? If both sides prove negative, how would one treat the patient? If the patient had classical symptoms but a normal sedimentation rate and negative biopsies bilaterally, 1339
OPHTHALMOLOGY •
NOVEMBER 1984 •
would one still treat the patient if vision loss had not occurred? What is the preferred treatment regimen for giant cell arteritis? How does one decide when to decrease therapy? To stop therapy? If major steroid complications intervene, but the disease is still active (sedimentation rate elevated), what should be done? How does one distinguish idiopathic ischemic optic neuropathy from idiopathic optic neuritis? Is arteriography or noninvasive carotid flow testing indicated in the assessment of the typical patient with idiopathic anterior ischemic optic neuropathy? What role, if any, should corticosteroids play in the management of idiopathic ischemic optic neuropathy?
REFERENCES 1. Miller NR. Anterior ischemic optic neuropathy: diagnosis and management. Bull NY Acad Med 1980; 56:643-54. 2. Miller GR, Smith JL. Ischemic optic neuropathy. Am J Ophthalmol 1966; 62:103-15.
VOLUME 91
•
NUMBER 11
3. Keltner JL. Giant-cell arteritis; signs and symptoms. Ophthalmology 1982; 89:1101-10. 4. Hayreh SS. Posterior ischemic optic neuropathy. Ophthalmologica 1981; 182:29-41. 5. Simmons RJ, Cogan DG. Occult temporal arteritis. Arch Ophthalmol 1962; 68:8-18. 6. Eshaghian J. Controversies regarding giant cell (temporal, cranial) arteritis. Doc Ophthalmol1979; 47:43-67. 7. Klein RG, Campbell RJ, Hunder GG, Carney JA. Skip lesions in temporal arteritis. Mayo Clin Proc 1976; 51:504-10. 8. Boghen DR, Glaser JS. lschaemic optic neuropathy; the clinical profile and history. Brain 1975; 98:689-708. 9. Lieberman MF, Shahi A, Green WR. Embolic ischemic optic neuropathy. Am J Ophthalmol1978; 86:206-10. 10. Hayreh SS. Anterior ischaemic optic neuropathy. Ill. Treatment, prophylaxis, and differential diagnosis. Br J Ophthalmol 1974; 58: 981-9. 11 . Foulds WS. Visual disturbances in systemic disorders: optic neuropathy and systemic disease. Trans Ophthalmol Soc UK 1969; 89:125-46. 12. Eagling EM, Sanders MD, Miller SJH. lschaemic papillopathy; clinical and fluorescein angiographic review of forty cases. Br J Ophthalmol 1974; 58:990-1008.
Discussion by Joel S. Glaser, MD, RobertS. Hepler, MD, Neil R. Miller, MD, H. Stanley Thompson, MD The panel considered Dr. Shults' questions individually: Temporal artery biopsy. A temporal artery biopsy should be done when the diagnosis is clinically suspected. Not only to confirm the diagnosis but also to support the use of steroids when, nine months later, someone reviews the case and says "Why have you got this lady on prednisone?" The initial decision to treat is usually made on the basis of history, the ocular findings, and an elevated erythrocyte sedimentation rate. If both temporal arteries are biopsied, one after the other, and both are read as negative, then the steroids would be slowly discontinued with an eye on the sedimentation rate and on other possible reasons for its elevation. Treatment of temporal arteritis. Temporal arteritis is treated with large doses of prednisone in order to prevent further visual loss. The usual starting dose is about I00 mg/day and the do~e is often kept over 40 mg/day for a month. The prednisone should be tapered slowly with a view of keeping the sedimentation rate low with a minimum amount of medication. Expect to continue this treatment for many months, sometimes for years. Unfortunately, in the event of steroid complications, no acceptable alternative treatment is available. Ischemic optic neuropathy versus optic neuritis. Usually there is little difficulty distinguishing anterior ischemic optic neuropathy from optic neuritis. Anterior ischemic optic neuropathy occurs in both sexes and is most common over the age of 50, whereas optic neuritis is more common in women, and under the age of 40. The field loss is quite different in the two conditions: in anterior ischemic optic neuropathy altitudinal
From the University of Iowa, Iowa City, Iowa.
1340
or disk-related field loss is the rule, although central visual loss occurs in perhaps one-third of the cases, whereas in optic neuritis a central scotoma is the rule at first but this soon clears up leaving patchy shallow paracentral defects that are hard to plot. Arcuate defects (disk-related) can occur in optic neuritis. The onset of the visual loss can be similar in the two conditions: In anterior ischemic optic neuropathy it may come on overnight, and in the next few days it may worsen. Generally, there is no pain. In optic neuritis, the visual deficit is often preceded by pain on eye movement, and the visual loss may gradually worsen for two to five days. The fundus appearance is quite different in the two conditions: In anterior ischemic optic neuropathy there is often regional swelling of the disk with striate hemorrhages, and in severe cases, a deep pallor. In optic neuritis the disk is usually normal, but in some cases there is a mild, diffuse disk swelling (papillitis). A pupil defect is visible in both conditions. In anterior ischemic optic neuropathy the size of the relative afferent pupil defect matches the field lost, but in optic neuritis the pupil defect may seem to exceed the field loss if you use kinetic perimetry. In summary, there is usually no difficulty in making the right diagnosis, but there is an area of overlap between the two conditions: if one sees a 45-year-old woman with painless arcuate field loss and a mildly swollen disk, it may be necessary to repeat the history of the onset, perform a neurological examination, and a visual evoked potential in each eye; even then the diagnosis may not be absolutely clear. Arteriography. This is not indicated in the assessment of a typical patient with idiopathic anterior ischemic optic neuropathy.
SHULTS
•
ISCHEMIC OPTIC NEUROPATHY
Steroid treatment for ischemic optic neuropathy. I think we are all in agreement that when part of the optic nerve head is completely infarcted, it is permanently infarcted and no amount of steroids will restore it to normal function. If this were the only kind of anterior ischemic optic neuropathy, then indeed there would be no place for steroids in its management. But some patients with anterior ischemic optic neuropathies lose more field after the first altitudinal field loss, while some improve. The defect is not always permanent and stable. Furthermore, it seems that an optic disk can suffer a hypoxic swelling without field loss. The swelling itself may contribute to fiber damage at the disk and thus produce loss of visual field. In this situation, reduction of the swelling by a short course of systemic steroids might be expected to be of some help. In giant cell arteritis there is a severe disk infarction which, as a rule, does not improve with steroids; nor does a massive nonarteritic infarction with pallid disk swelling. It seems reasonable to assume that in these cases there has actually been an occlusion of a posterior ciliary artery. It isn't necessary for a vessel to become actually occluded to cause hypoxic damage; a temporary drop in perfusion pressure is all that is
required. This may be why many patients awaken with an ischemic optic neuropathy. If the blood pressure drops a few points during the night and the intraocular pressure goes up transiently as the patient rests an eye on a pillow, this may impair perfusion enough to cause a hypoxic swelling of the disk and thus a disk-related field loss. If some of this field loss is potentially reversible, then I believe that a course of steroids is worth trying, though it seems most of my colleagues on this panel disagree. We use 80 to 100 mg prednisone for two weeks, and if the field loss does not improve we taper the dosage during the following two weeks. In general, we try to keep the dose at at least 40 mg/day as long as the disk is swollen. Most patients receive three to six weeks of tapering steroids. We have not been troubled with drug-induced complications, and a sizeable percentage of our patients have shown improvement of their visual field loss. Of course, it still has not been proven that the steroids are doing more good than harm. The only way to settle this is with a carefully designed therapeutic trial which is difficult and expensive to arrange. H. STANLEY THOMPSON, MD
1341