Convergence Insufficiency Associated with Migraine: A Case Series Eric L. Singman, M.D., Ph.D.1 Noelle S. Matta, C.O., C.R.C., C.O.T.2 David I. Silbert, M.D., F.A.A.P.2
ABSTRACT Background and Purpose: The appearance of convergence insufficiency in migraineurs suggests a possible link between migraine and convergence insufficiency. Patients and Method: Relevant patients reporting to our neuro-ophthalmology clinic complained of symptoms consistent with convergence insufficiency and had a history of migraine. Patients underwent thorough neuro-ophthalmic evaluations including history, physical exam, and cranial imaging. Four illustrative cases are presented in this report. Results: Convergence insufficiency may develop after migraine. In some cases, it may be a persistent cause of reduced visual functioning. In patients with persistent asthenopia, orthoptic therapy has proven successful. Conclusions: A history of migraine should be sought in patients complaining of reading difficulties secondary to new onset convergence insufficiency. Furthermore, migraineurs should be asked about whether they suffer asthenopia. Finally, a larger scale, prospective study should be considered to further explore a possible link between migraine and convergence insufficiency.
INTRODUCTION
From 1Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, and 2Family Eye Group, Lancaster, Pennsylvania. Requests for reprints should be addressed to: Noelle S. Matta, C.O., C.R.C., C.O.T., Family Eye Group, Vision Research Department, 2110 Harrisburg Pike, Suite 215, Lancaster, PA 17601.
Convergence insufficiency (CI) is a common and treatable cause of asthenopia (eye strain) characterized by an exophoria at near, a reduced near point of convergence, and / or reduced convergence amplitudes.1 Convergence amplitude testing usually reproduces the patient’s symptoms. This condition is usually amenable to simple orthoptic exercises.2 Convergence insuffi-
© 2014 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448
112
SINGMAN
ciency is often idiopathic, but can also be seen secondary to head injury, aging, Lyme disease, Parkinsonism, and illnesses associated with fatigue, such as anemia and myasthenia gravis.3 Migraine headache is known to cause ophthalmoplegia, although the symptoms usually resolve spontaneously along with the migraine.4 Stroke-like symptoms, such as cranial nerve palsy, can be associated with complicated migraine.5, 6 When double vision results in these cases, there is usually clear evidence of neuropathy and healing occurs along the same time frame as might ischemic cranial neuropathy from other etiologies. We present the first published cases of new-onset classic convergence insufficiency occurring acutely after migraine. MATERIALS AND METHODS We identified patients suffering convergence insufficiency, which developed shortly after experiencing migraine. In all cases, the patients were examined in our neuro- and pediatric ophthalmology clinic and treated by our certified orthoptist. The diagnosis of convergence insufficiency was made based upon reduced convergence amplitudes.7 The diagnosis of migraine was made based upon the criteria described by the International Headache Society’s The International Classification of Headache Disorders.8 Prior to starting this research we received Institutional Review Board (IRB) approval through the Lancaster General Hospital IRB. We received a waiver of consent due to the low risk of this research and followed appropriate Health Insurance Portability and Accountability Act of 1996 guidelines. RESULTS Patient One is a 26-year-old man presenting to our clinic in January 2008. He complained that he had blurred vision of sudden onset lasting approximately 90
American Orthoptic Journal
minutes two weeks prior to his examination. He indicated that he felt as if he were looking through water while he was driving. He denied dizziness and nausea, but he did have a severe headache. The patient added that aside from this episode, he suffers frequent headaches behind his eyes that start soon after awakening. He finds no relief from using large doses of acetaminophen. During his examination, we measured his convergence amplitudes at 16Δ base-out at near, and this testing reproduced his symptoms. His refractive error was negligible, vergences were full, and there was no strabismus. The patient was offered a work-up including MRI of the brain (which was normal) and migraine specific medication. A diagnosis of migraine was made based upon the history and benign results of further work-up. At his follow-up visit, the patient reported that the headaches were much less but reading was still too difficult and uncomfortable. We initiated orthoptic therapy with the Brock String9 and his symptoms resolved 3 months later. Patient Two is a 44-year-old woman presenting to our clinic in September 2006. She complained of “fluctuating” vision and that she could not read despite changing glasses. The problem occurred all day long for at least a few hours each day and had been extant for the 5 months prior to her visit with us. The patient also mentioned that she had developed a tendency to feel carsick while driving during this period. The patient had a documented, long history of migraines. On physical exam, we found that her convergence amplitudes were 25Δ BO at near and testing reproduced her symptoms. Her family doctor had ordered an MRI of the brain, which showed a few hyper-intense white matter lesions, called “nonspecific” by the reading radiologist although these lesions can be seen in migraineurs. The patient was offered orthoptic therapy but declined. She returned in January 2007 with no change
113
CONVERGENCE INSUFFICIENCY
in her complaints or her exam. In April 2007, the patient returned because her migraines increased in frequency and her reading disability worsened. Another MRI of the brain was performed just prior to that visit and it was read as entirely stable compared to the previous study. However, the patient’s convergence amplitudes had decreased to 12Δ BO at near and the patient accepted the responsibility of performing orthoptic exercises with the Brock String. The patient confirmed that the exercises successfully relieved her symptoms and she was reading comfortably again. She was placed on antimigraine prophylaxis and neither the migraines nor the convergence insufficiency returned. Patient Three is a 60-year-old woman with a known history of migraine for many years prior to her visit to our clinic in February 2007. At that time, she reported that for the previous 3 months, she could only read for 15 minutes before her vision blurred. Her migraines can be severe, sometimes requiring intramuscular injections of painkillers, including twice in the year prior to her visit. During her examination, we measured her convergence amplitudes at 16Δ BO at near, reproducing her symptoms. The patient had a work-up initiated by her family doctor, including a CT scan of the head reported as negative. The patient was prescribed orthoptic therapy with the Brock String and within 1 month, the patient reported significantly improved reading ability. Convergence amplitudes in March 2007 were improved at 30Δ BO. The patient returned in April 2007 and reported that things had worsened. Notably, her convergence amplitudes had decreased to 18Δ BO at near. Upon further history taking, the patient reported a “bad” migraine 2 weeks prior to this visit. The patient was prescribed the home-based computer orthoptic computer program and counseled that if she did not enjoy therapeutic success to return as needed. When seen a year later, she was asymptomatic.
114
Patient Four is a 27-year-old woman with a history of two confirmed migraine headaches occurring in the past 6 months preceding her visit to our clinic in November 2007; the more recent episode was within the week prior to the visit. Her family doctor initiated a work-up, including a CT scan, which was negative. The patient was not an avid reader and did not describe problems reading. However, she did describe recent difficulty and ocular discomfort playing volleyball although she was unsure how to describe these symptoms. Convergence testing reproduced the visual symptoms and we measure her amplitudes to be 12Δ BO at near. We instructed the patient on the use of the Brock String. Through telephone follow up, the patient indicated that the exercises helped relieve her ocular complaints. DISCUSSION Migraine is a common, neurologic condition, generally felt to be transient, in which there is a reversible spreading depression of cerebral cortical function.10 This change is associated with alterations in cerebral blood flow. As the blood flood to the brain returns to normal, the blood vessels in the brain may dilate in a pulsatile way, manifesting as a throbbing, severe headache.9 Migraine can be associated with aura; a constellation of neurologic symptoms, including dizziness, tinnitus, scotomata, photo- or phono-phobia; and visual hallucinations (such as zigzag lines), also called scintillating scotomata.12 Less commonly, migraine aura can also occur without any headache, an event termed acephalgic migraine.13 In some cases, migraine may leave chronic defects, and a patient will appear to have suffered a cerebrovascular accident, a condition called complicated migraine.14 That migraine can cause ophthalmoloplegia is well documented.4 However, in these cases, patients are left with evi-
Volume 64, 2014
SINGMAN
dence of transient or chronic strabismus. Usually, extraocular motility testing will help localize the defect to a cranial nerve or multiple cranial nerves. To our knowledge, there have not been documented cases of typical convergence insufficiency associated with the post-migraine period. Patient One suffered convergence insufficiency as well as migraines. Although we cannot be sure that there was a particular migraine episode that triggered the CI, it seems likely that the migraine process was associated. Importantly, although the patient’s headaches improved after appropriate migraine-directed therapy, the CI remained and required orthoptic therapy. This suggests that while migraines might initiate CI, resolution of migraine does not automatically lead to resolution of CI. Patient Two is a migraineur who developed significant asthenopia from CI. Her case was remarkable for the fact that her CI worsened over time rather than improved and this worsening was contemporaneous with an increase in her migraine frequency. It could be argued that migraine leads to worsening convergence insufficiency as patients avoid near tasks and perhaps thereby develop a disuse atrophy of their convergence facilities. However, Patient Three’s situation does seem to make the case that migraine might not only cause but also worsen CI. This patient showed improvement with orthoptic exercises, but regressed in a short period after suffering a migraine. Patient Four was notable for the fact that she did not initially complain of asthenopia with reading. However, upon further history, she was not an avid reader and might not have noticed asthenopia if her reading tasks tended to be brief or cursory. Although the CI might have started anytime, her visual complaints apparently became manifest and were detected after the migraines began and seemed to be temporally associated with them. Furthermore, her case highlights the need to ask
American Orthoptic Journal
patients about any and all visual tasks for which they sense suboptimal functioning; CI can affect distance vision as well as the ability to track an incoming object. CONCLUSION The convergence process is complex and the neurologic pathways subserving convergence are not completely understood in humans. It is likely that these pathways span a large portion of the brain, including afferent pathways from the optic nerve to the thalamus to the visual cortex and efferent pathways including the extrastriate cortex, frontal cortex, pontine nuclei, cerebellar cortex, and vestibular nuclei to the ocular motor neurons. If further studies confirm our suggestion that migraine can indeed be associated causally with convergence insufficiency, then we might be able to use the information to further our understanding of the anatomic basis of convergence insufficiency and the convergence mechanisms in general. Radiologic studies of our patients suggested that none suffered a complicated migraine during which there might have been an ischemic event in the convergence pathways. It would appear that migraine might be associated with a global change to cortical function and somehow the convergence mechanism is damaged, perhaps in the way concussion might cause CI. Migraine is common, occurring in 5.6% of men and over 17% of women.15 Convergence insufficiency is very common, affecting most people over the age of 40 years,16 although it should be mentioned that two of the four patients presented were under age 40. Most convergence insufficiency associated with migraine responded readily to orthoptic exercises, possibly due to its relatively short duration. Based upon our study, it would seem reasonable to ask migraine patients about visual complaints, particularly asthenopia, and to explore for the history of migraine in patients with
115
CONVERGENCE INSUFFICIENCY
new onset CI. Further, it may be useful to consider larger, prospective studies to explore a possible link between migraine and convergence insufficiency.
8.
9.
REFERENCES 1. Convergence Insufficiency Treatment Trial Study Group: Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol 2008; 126:13361349. 2. von Noorden GK, et al. Binocular Vision and Ocular Motility, 6th ed. St. Louis: Mosby; 2002, pp. 500-502. 3. Rucker JC: Neuro-ophthalmology of systemic disease. Semin Neurol 2009; 29:111-123. 4. Bek S, Genc G, Demirkaya S, Eroglu E, Odabasi Z: Ophthalmoplegic migraine. Neurologist 2009; 15:147-149. 5. Pezzini A, Del Zotto E, Giossi A, Volonghi I, Grassi M, Padovani A: The migraine ischemic stroke connection: Potential pathogenic mechanisms. Curr Mol Med 2009; 9:215-226. 6. Welch KM, Levine SR: Migraine-related stroke in the context of the International Headache Society Classification of head pain. Arch Neurol 1990; 47:458-462. 7. Wright KW, Spiegel PH, eds. The Requisites in
116
10. 11.
12. 13.
14. 15.
16.
Opthalmology: Pediatric Ophthalmology and Strabismus. St. Louis: Mosby; 1999, p. 250. International Headache Society. IHS Classification ICHD-II. http: // his-classification.org / en / 01_einleitung / 02_einleitunk 2003-2005. Aziz S, et al.: Are orthoptic exercises an effective treatment for convergence and fusion deficiencies? Strabismus 2006; 14:183-189. Schwedt TJ, Dodick DW: Advanced neuroimaging of migraine. Lancet Neurol 2009; 8:560-568. Arulmozhi DK, Veeranjaneyulu A, Bodhankar SL: Migraine: Current therapeutic targets and future avenues. Curr Vasc Pharmacol 2006; 4:117-128. Reinecke RD, Silberstein SD: Migrainous visual auras: A life history. Headache 2007; 47:123-127. Kunkel RS: Migraine aura without headache: Benign, but a diagnosis of exclusion. Cleve Clin J Med 2005; 72:529-534. Elliott D: Migraine and stroke: Current perspectives. Neurol Res 2008; 30:801-812. Tepper SJ: A pivotal moment in 50 years of headache history: The first American Migraine Study. Headache 2008; 48:730-732. Abdi S, Rydberg A: Asthenopia in schoolchildren: Orthoptic and ophthalmological findings and treatment. Doc Ophthalmol 2005; 111:65-72.
Key words: migraine, convergence insufficiency, asthenopia
Volume 64, 2014
ABSTRACT Background and Purpose: The appearance of convergence insufficiency in migraineurs suggests a possible link between migraine and convergence insufficiency. Patients and Method: Relevant patients reporting to our neuro-ophthalmology clinic complained of symptoms consistent with convergence insufficiency and had a history of migraine. Patients underwent thorough neuro-ophthalmic evaluations including history, physical exam, and cranial imaging. Four illustrative cases are presented in this report. Results: Convergence insufficiency may develop after migraine. In some cases, it may be a persistent cause of reduced visual functioning. In patients with persistent asthenopia, orthoptic therapy has proven successful. Conclusions: A history of migraine should be sought in patients complaining of reading difficulties secondary to new onset convergence insufficiency. Furthermore, migraineurs should be asked about whether they suffer asthenopia. Finally, a larger scale, prospective study should be considered to further explore a possible link between migraine and convergence insufficiency.
INTRODUCTION
From 1Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, and 2Family Eye Group, Lancaster, Pennsylvania. Requests for reprints should be addressed to: Noelle S. Matta, C.O., C.R.C., C.O.T., Family Eye Group, Vision Research Department, 2110 Harrisburg Pike, Suite 215, Lancaster, PA 17601.
Convergence insufficiency (CI) is a common and treatable cause of asthenopia (eye strain) characterized by an exophoria at near, a reduced near point of convergence, and / or reduced convergence amplitudes.1 Convergence amplitude testing usually reproduces the patient’s symptoms. This condition is usually amenable to simple orthoptic exercises.2 Convergence insuffi-
© 2014 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448
112
SINGMAN
ciency is often idiopathic, but can also be seen secondary to head injury, aging, Lyme disease, Parkinsonism, and illnesses associated with fatigue, such as anemia and myasthenia gravis.3 Migraine headache is known to cause ophthalmoplegia, although the symptoms usually resolve spontaneously along with the migraine.4 Stroke-like symptoms, such as cranial nerve palsy, can be associated with complicated migraine.5, 6 When double vision results in these cases, there is usually clear evidence of neuropathy and healing occurs along the same time frame as might ischemic cranial neuropathy from other etiologies. We present the first published cases of new-onset classic convergence insufficiency occurring acutely after migraine. MATERIALS AND METHODS We identified patients suffering convergence insufficiency, which developed shortly after experiencing migraine. In all cases, the patients were examined in our neuro- and pediatric ophthalmology clinic and treated by our certified orthoptist. The diagnosis of convergence insufficiency was made based upon reduced convergence amplitudes.7 The diagnosis of migraine was made based upon the criteria described by the International Headache Society’s The International Classification of Headache Disorders.8 Prior to starting this research we received Institutional Review Board (IRB) approval through the Lancaster General Hospital IRB. We received a waiver of consent due to the low risk of this research and followed appropriate Health Insurance Portability and Accountability Act of 1996 guidelines. RESULTS Patient One is a 26-year-old man presenting to our clinic in January 2008. He complained that he had blurred vision of sudden onset lasting approximately 90
American Orthoptic Journal
minutes two weeks prior to his examination. He indicated that he felt as if he were looking through water while he was driving. He denied dizziness and nausea, but he did have a severe headache. The patient added that aside from this episode, he suffers frequent headaches behind his eyes that start soon after awakening. He finds no relief from using large doses of acetaminophen. During his examination, we measured his convergence amplitudes at 16Δ base-out at near, and this testing reproduced his symptoms. His refractive error was negligible, vergences were full, and there was no strabismus. The patient was offered a work-up including MRI of the brain (which was normal) and migraine specific medication. A diagnosis of migraine was made based upon the history and benign results of further work-up. At his follow-up visit, the patient reported that the headaches were much less but reading was still too difficult and uncomfortable. We initiated orthoptic therapy with the Brock String9 and his symptoms resolved 3 months later. Patient Two is a 44-year-old woman presenting to our clinic in September 2006. She complained of “fluctuating” vision and that she could not read despite changing glasses. The problem occurred all day long for at least a few hours each day and had been extant for the 5 months prior to her visit with us. The patient also mentioned that she had developed a tendency to feel carsick while driving during this period. The patient had a documented, long history of migraines. On physical exam, we found that her convergence amplitudes were 25Δ BO at near and testing reproduced her symptoms. Her family doctor had ordered an MRI of the brain, which showed a few hyper-intense white matter lesions, called “nonspecific” by the reading radiologist although these lesions can be seen in migraineurs. The patient was offered orthoptic therapy but declined. She returned in January 2007 with no change
113
CONVERGENCE INSUFFICIENCY
in her complaints or her exam. In April 2007, the patient returned because her migraines increased in frequency and her reading disability worsened. Another MRI of the brain was performed just prior to that visit and it was read as entirely stable compared to the previous study. However, the patient’s convergence amplitudes had decreased to 12Δ BO at near and the patient accepted the responsibility of performing orthoptic exercises with the Brock String. The patient confirmed that the exercises successfully relieved her symptoms and she was reading comfortably again. She was placed on antimigraine prophylaxis and neither the migraines nor the convergence insufficiency returned. Patient Three is a 60-year-old woman with a known history of migraine for many years prior to her visit to our clinic in February 2007. At that time, she reported that for the previous 3 months, she could only read for 15 minutes before her vision blurred. Her migraines can be severe, sometimes requiring intramuscular injections of painkillers, including twice in the year prior to her visit. During her examination, we measured her convergence amplitudes at 16Δ BO at near, reproducing her symptoms. The patient had a work-up initiated by her family doctor, including a CT scan of the head reported as negative. The patient was prescribed orthoptic therapy with the Brock String and within 1 month, the patient reported significantly improved reading ability. Convergence amplitudes in March 2007 were improved at 30Δ BO. The patient returned in April 2007 and reported that things had worsened. Notably, her convergence amplitudes had decreased to 18Δ BO at near. Upon further history taking, the patient reported a “bad” migraine 2 weeks prior to this visit. The patient was prescribed the home-based computer orthoptic computer program and counseled that if she did not enjoy therapeutic success to return as needed. When seen a year later, she was asymptomatic.
114
Patient Four is a 27-year-old woman with a history of two confirmed migraine headaches occurring in the past 6 months preceding her visit to our clinic in November 2007; the more recent episode was within the week prior to the visit. Her family doctor initiated a work-up, including a CT scan, which was negative. The patient was not an avid reader and did not describe problems reading. However, she did describe recent difficulty and ocular discomfort playing volleyball although she was unsure how to describe these symptoms. Convergence testing reproduced the visual symptoms and we measure her amplitudes to be 12Δ BO at near. We instructed the patient on the use of the Brock String. Through telephone follow up, the patient indicated that the exercises helped relieve her ocular complaints. DISCUSSION Migraine is a common, neurologic condition, generally felt to be transient, in which there is a reversible spreading depression of cerebral cortical function.10 This change is associated with alterations in cerebral blood flow. As the blood flood to the brain returns to normal, the blood vessels in the brain may dilate in a pulsatile way, manifesting as a throbbing, severe headache.9 Migraine can be associated with aura; a constellation of neurologic symptoms, including dizziness, tinnitus, scotomata, photo- or phono-phobia; and visual hallucinations (such as zigzag lines), also called scintillating scotomata.12 Less commonly, migraine aura can also occur without any headache, an event termed acephalgic migraine.13 In some cases, migraine may leave chronic defects, and a patient will appear to have suffered a cerebrovascular accident, a condition called complicated migraine.14 That migraine can cause ophthalmoloplegia is well documented.4 However, in these cases, patients are left with evi-
Volume 64, 2014
SINGMAN
dence of transient or chronic strabismus. Usually, extraocular motility testing will help localize the defect to a cranial nerve or multiple cranial nerves. To our knowledge, there have not been documented cases of typical convergence insufficiency associated with the post-migraine period. Patient One suffered convergence insufficiency as well as migraines. Although we cannot be sure that there was a particular migraine episode that triggered the CI, it seems likely that the migraine process was associated. Importantly, although the patient’s headaches improved after appropriate migraine-directed therapy, the CI remained and required orthoptic therapy. This suggests that while migraines might initiate CI, resolution of migraine does not automatically lead to resolution of CI. Patient Two is a migraineur who developed significant asthenopia from CI. Her case was remarkable for the fact that her CI worsened over time rather than improved and this worsening was contemporaneous with an increase in her migraine frequency. It could be argued that migraine leads to worsening convergence insufficiency as patients avoid near tasks and perhaps thereby develop a disuse atrophy of their convergence facilities. However, Patient Three’s situation does seem to make the case that migraine might not only cause but also worsen CI. This patient showed improvement with orthoptic exercises, but regressed in a short period after suffering a migraine. Patient Four was notable for the fact that she did not initially complain of asthenopia with reading. However, upon further history, she was not an avid reader and might not have noticed asthenopia if her reading tasks tended to be brief or cursory. Although the CI might have started anytime, her visual complaints apparently became manifest and were detected after the migraines began and seemed to be temporally associated with them. Furthermore, her case highlights the need to ask
American Orthoptic Journal
patients about any and all visual tasks for which they sense suboptimal functioning; CI can affect distance vision as well as the ability to track an incoming object. CONCLUSION The convergence process is complex and the neurologic pathways subserving convergence are not completely understood in humans. It is likely that these pathways span a large portion of the brain, including afferent pathways from the optic nerve to the thalamus to the visual cortex and efferent pathways including the extrastriate cortex, frontal cortex, pontine nuclei, cerebellar cortex, and vestibular nuclei to the ocular motor neurons. If further studies confirm our suggestion that migraine can indeed be associated causally with convergence insufficiency, then we might be able to use the information to further our understanding of the anatomic basis of convergence insufficiency and the convergence mechanisms in general. Radiologic studies of our patients suggested that none suffered a complicated migraine during which there might have been an ischemic event in the convergence pathways. It would appear that migraine might be associated with a global change to cortical function and somehow the convergence mechanism is damaged, perhaps in the way concussion might cause CI. Migraine is common, occurring in 5.6% of men and over 17% of women.15 Convergence insufficiency is very common, affecting most people over the age of 40 years,16 although it should be mentioned that two of the four patients presented were under age 40. Most convergence insufficiency associated with migraine responded readily to orthoptic exercises, possibly due to its relatively short duration. Based upon our study, it would seem reasonable to ask migraine patients about visual complaints, particularly asthenopia, and to explore for the history of migraine in patients with
115
CONVERGENCE INSUFFICIENCY
new onset CI. Further, it may be useful to consider larger, prospective studies to explore a possible link between migraine and convergence insufficiency.
8.
9.
REFERENCES 1. Convergence Insufficiency Treatment Trial Study Group: Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol 2008; 126:13361349. 2. von Noorden GK, et al. Binocular Vision and Ocular Motility, 6th ed. St. Louis: Mosby; 2002, pp. 500-502. 3. Rucker JC: Neuro-ophthalmology of systemic disease. Semin Neurol 2009; 29:111-123. 4. Bek S, Genc G, Demirkaya S, Eroglu E, Odabasi Z: Ophthalmoplegic migraine. Neurologist 2009; 15:147-149. 5. Pezzini A, Del Zotto E, Giossi A, Volonghi I, Grassi M, Padovani A: The migraine ischemic stroke connection: Potential pathogenic mechanisms. Curr Mol Med 2009; 9:215-226. 6. Welch KM, Levine SR: Migraine-related stroke in the context of the International Headache Society Classification of head pain. Arch Neurol 1990; 47:458-462. 7. Wright KW, Spiegel PH, eds. The Requisites in
116
10. 11.
12. 13.
14. 15.
16.
Opthalmology: Pediatric Ophthalmology and Strabismus. St. Louis: Mosby; 1999, p. 250. International Headache Society. IHS Classification ICHD-II. http: // his-classification.org / en / 01_einleitung / 02_einleitunk 2003-2005. Aziz S, et al.: Are orthoptic exercises an effective treatment for convergence and fusion deficiencies? Strabismus 2006; 14:183-189. Schwedt TJ, Dodick DW: Advanced neuroimaging of migraine. Lancet Neurol 2009; 8:560-568. Arulmozhi DK, Veeranjaneyulu A, Bodhankar SL: Migraine: Current therapeutic targets and future avenues. Curr Vasc Pharmacol 2006; 4:117-128. Reinecke RD, Silberstein SD: Migrainous visual auras: A life history. Headache 2007; 47:123-127. Kunkel RS: Migraine aura without headache: Benign, but a diagnosis of exclusion. Cleve Clin J Med 2005; 72:529-534. Elliott D: Migraine and stroke: Current perspectives. Neurol Res 2008; 30:801-812. Tepper SJ: A pivotal moment in 50 years of headache history: The first American Migraine Study. Headache 2008; 48:730-732. Abdi S, Rydberg A: Asthenopia in schoolchildren: Orthoptic and ophthalmological findings and treatment. Doc Ophthalmol 2005; 111:65-72.
Key words: migraine, convergence insufficiency, asthenopia
Volume 64, 2014
