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Ultrasound assessment of optic disc edema in patients with headache
American Journal of Emergency Medicine (2012) 30, 1654.e1–1654.e4
www.elsevier.com/locate/ajem
Case Report Ultrasound assessment of optic disc edema in patients with headache Abstract Point-of-care ocular ultrasonography is emerging as a powerful tool to evaluate emergency department (ED) patients at risk for ophthalmologic and intracranial pathology. We present cases of 3 patients in whom optic disc swelling was identified using ocular ultrasound. Causes for optic disc swelling in our patients included idiopathic intracranial hypertension, secondary syphilis, and malignant hypertension with associated hypertensive retinopathy. Because direct visualization of the optic disc may be challenging in an ED setting, ultrasound examination of the optic disc may represent an important adjunct to fundoscopy when assessing patients with headache or visual complaints. Point-of-care ocular ultrasonography is emerging as a useful tool for the evaluation of patients at risk for ophthalmologic and intracranial pathology. Emergency physician–performed sonography appears to be a sensitive screening test for various ocular conditions including traumatic injuries, retinal vascular insult, and retinal detachment [1,2]. In addition, measurement of the retrobulbar optic nerve sheath diameter (ONSD) has been investigated as a means of noninvasively assessing intracranial pressure [2,3]. To date, however, little data exist on the performance of point-of-care sonography to assess swelling to the optic disc. Although direct visualization using an ophthalmoscope is considered the standard method of assessing the appearance of the fundus, it may be difficult or impossible to perform this effectively, especially in an ED setting [4-6]. Because optic disc swelling is always abnormal, a reliable method to assess patients at risk for this condition is of critical importance to the emergency physician. Below, we describe 3 cases in which point-of-care ultrasound was used to accurately identify optic disc edema in emergency department (ED) patients with various underlying diagnoses. The patient lies supine with the head in neutral position and is instructed to close both eyes. A small amount of ultrasound gel is placed over the closed eyelid, or a nonadhesive clear dressing may be placed over the eyelid to 0735-6757/$ – see front matter © 2012 Elsevier Inc. All rights reserved.
protect the eye from the gel. A high-frequency (10-13 MHz) linear array transducer with a Sonosite M-Turbo (Bothell, WA) is placed lightly on the lid. We recommend that the operator's fingers be braced on the bridge of the nose or forehead to minimize pressure on the globe (Fig. 1). The patient is instructed to look straight ahead, and the globe is scanned in the axial plane until a clear image of the optic disc is obtained. When the optic disc is isolated, it should be measured from its base to maximal height (Fig. 2A, normal landmarks). A 19-year-old woman was sent to the ED by her ophthalmologist for evaluation of persistent headache and decreasing peripheral vision. She reported approximately 6 months of gradually worsening blurry vision and diffuse headache associated with nausea. She had no additional medical problems and denied alcohol, tobacco, and drug use. On the day of presentation, she saw her ophthalmologist who noted bilateral optic disc swelling on examination and referred her to the ED for further evaluation. On evaluation, the patient's vital signs were normal. Her physical examination was notable for morbid obesity and bilateral optic disc swelling on fundoscopy (Fig. 3). Her visual acuity and visual fields were normal. An ocular ultrasound demonstrated significant swelling of bilateral optic discs (Fig. 2C, papilledema in idiopathic intracranial hypertension retinal base (thick arrow) with swollen optic disc [thin arrow]). A computed tomographic scan of her head
Fig. 1
Recommended technique for ocular ultrasound.
1654.e2
Case Report
Fig. 2 A, Normal ocular ultrasound landmarks; B, Hypertensive ischemic papillitis with retinal base [thick arrow] and swollen optic disc [thin arrow]; C, Papilledema in idiopathic intracranial hypertension with retinal base [thick arrow] and swollen optic disc [thin arrow]; D, Neurosyphilis induced optic disc swelling with height measurement.
showed no abnormalities. A lumbar puncture was performed in the ED. The opening pressure was markedly elevated at 51 cm, but analysis of the cerebrospinal fluid analysis was otherwise normal. Her symptoms significantly resolved after the procedure. Of note, however, her optic disc swelling persisted when she was evaluated with a repeat bedside sonogram 24 hours later, a finding that reflects the underlying pathophysiology of papilledema as a consequence of impairment of retrograde axoplasmic transport within the
Fig. 3 Fundoscopy of optic disc edema demonstrating blurred disc margins.
optic nerve rather than a direct result of the hydrostatic pressure of the cerebrospinal fluid (CSF) on the nerve head. The patient was diagnosed with idiopathic intracranial hypertension (IIH) and admitted to the hospital for further management. Her pain was controlled, and she was started on acetazolamide and topiramate. Her headache symptoms improved, and on follow-up with her ophthalmologist 3 months later, her papilledema had entirely resolved. A 36-year-old man with no prior medical history was transferred to our ED from a community clinic to be evaluated for hypertension. He reported several weeks of headache and blurry vision and had a blood pressure of 235/ 140 at triage. He denied chest pain, shortness of breath, or other symptoms. He smoked cigarettes and drank alcohol occasionally but denied illicit drug use. On further evaluation, a repeat blood pressure measurement remained elevated at 198/131, but vital signs were otherwise normal. His physical examination was unremarkable with the exception of bilateral optic disc swelling noted on fundoscopy. Ocular ultrasound demonstrated significant swelling of both optic Retinal base discs with the right eye more severely affected (Fig. 2B, [thick arrow] with swollen optic disc [thin arrow]). The patient was admitted to the hospital for blood pressure control. A subsequent noncontrast computed tomographic scan of the brain was unremarkable. The ophthalmology service evaluated the patient and confirmed examination findings consistent with severe hypertensive
Case Report retinopathy. The patient's blood pressure was controlled with intravenous and oral medications during his admission. He was ultimately discharged home on oral blood pressure agents but was lost to follow-up before further outpatient workup for his hypertension could be undertaken. A 41-year-old man with HIV was evaluated in our ED for 1 day of cloudiness and “darkening” of the peripheral vision in his right eye. He denied diplopia, flashing lights, floaters, headache, fevers, neck stiffness, focal weakness, or associated trauma. He had been diagnosed with HIV 3 years prior and had started antiretroviral therapy 6 weeks before the onset of his symptoms. He had no coexisting medical problems and denied tobacco, alcohol, and drug use. On initial evaluation in the ED, the patient's vital signs and general physical examination were normal. His visual acuity, visual fields, intraocular pressures, extraocular movements, and pupils were normal. No abnormalities were noted in the anterior segment of either eye; however, the optic discs were not well seen on initial evaluation in the ED. Point-of-care sonography revealed significant swelling of both optic discs. The findings were more severe in the right eye in which the apex of the disc was noted to bulge anteriorly approximately 1.5 mm relative to the surface of the retina (Fig. 2D). A subsequent magnetic resonance imaging confirmed bilateral optic disc edema, but no abnormal findings were noted in the brain. A lumbar puncture yielded spinal fluid containing 10 white blood cells per high-power field, 15 red blood cells per high-power field, glucose of 52, and total protein of 57. The opening pressure was normal at 14 cm. Serum and CSF cryptococcal antigen tests were negative. The gram stain and bacterial culture of the CSF were both negative; however, CSF Venereal Disease Research Laboratory test as well as serum rapid plasma reagin (titer 256:1) and serum treponemal antibody tests were positive. The patient was diagnosed with neurosyphilis with associated papillitis. He was treated with a 5-week course of penicillin. On follow-up with neurology and ophthalmology, the patient had no further symptoms and was noted to have resolution of the optic disc swelling in both eyes. As the cases above illustrate, point-of-care ocular ultrasonography can be a useful diagnostic tool for assessing swelling of the optic disc from a variety of causes. In an ED setting, numerous obstacles may prevent an accurate assessment of the appearance of the optic disc using a traditional ophthalmoscope. Thus, we believe that the technique described above may prove to be a valuable adjunct to the standard ocular examination. A rich differential diagnosis exists for the underlying causes of optic disc edema; however, of greatest clinical importance to the emergency physician is the ability to detect elevated intracranial pressure (ICP), either from an intracranial mass lesion or from IIH. The presence of disc swelling demands prompt subsequent evaluation, usually with neuroimaging and a lumbar puncture. When optic disc swelling is bilateral and caused by elevated ICP, it is correctly termed papilledema. As
1654.e3 illustrated above, disc edema can result from other causes as well, specifically ischemia caused by malignant hypertension, inflammation caused by conditions such as sarcoidosis or multiple sclerosis, or with infections such as neurosyphilis. In these cases, the disc edema is referred to as “papillitis.” If no evidence of elevated ICP is uncovered, a search for one of these underlying etiologies should be undertaken. What is the relationship between the presence of optic disc swelling and the diameter of the retrobulbar optic nerve sheath? Current literature in traumatic brain injury indicates that ONSD of 5.7 to 6 mm is accurate in predicting elevated ICP in both the intensive care unit setting [7] and in the ED screening [8,9], although these findings did not attempt to characterize the appearance of the optic disc. One prospective ED and intensive care unit study compared ultrasound ONSD measurements and invasive ICP monitoring, showing that an ONSD of greater than 5 mm correlated to an ICP greater than 20 mm Hg [3]. One prior ED case report describes nerve sheath enlargement (ONSDs of 6.9 and 7.1 mm) in addition to visible optic disc bulging in a patient with significantly elevated ICP due to idiopathic intracranial hypertension, suggesting a possible relationship [10]. It should be mentioned, however, that controversy exists as to the reliability of the technique used to measure the ONSD in these studies [11,12]. Thus, any relationship between sonographic measurements of ONSD and the presence of optic disc swelling remains an open question. One final point deserved mention: The degree of swelling visualized on bedside sonography that represents true underlying pathology has yet to be determined. Our clinical experience suggests that the optic disc is visible in many healthy patients but appears significantly smaller than in any patients described present. We recommend that any significant degree of disc swelling be further referred for expert evaluation if uncertainty exists, although literature in the ophthalmologic journals suggests that ultrasonographic measurements may accurately assess the presence of optic disc swelling when compared with the criterion standard of measurement, confocal scanning laser ophthalmoscope measurements [13]. Bedside ultrasonography appears to be a promising modality to improve clinical examination skills in evaluating ocular pathology in the ED. More study is needed to determine physician accuracy and test characteristics of bedside ultrasound in detecting optic disc swelling. However, because direct visualization of the optic disc may be challenging in an ED setting, ultrasound examination of the optic disc may represent an important adjunct to fundoscopy when assessing patients with headache or visual complaints. Siri Daulaire MD Department of Emergency Medicine Rhode Island Hospital Providence, RI E-mail address: [email protected]
1654.e4
Case Report Lauren Fine MD Department of Emergency Medicine Alameda County Medical Center Oakland, CA
Margaret Salmon MD Department of Emergency Medicine University of California at San Francisco Medical Center San Francisco, CA Catherine Cummings MD Otto Liebmann MD Department of Emergency Medicine Rhode Island Hospital Providence, RI Sachita Shah MD, RDMS Division of Emergency Medicine Harborview Medical Center Seattle, WA Nathan Teismann MD Department of Emergency Medicine University of California at San Francisco Medical Center San Francisco, CA doi:10.1016/j.ajem.2011.06.030
References [1] Shinar Z, Chan L, Orlinsky M. Use of ocular ultrasound for the evaluation of retinal detachment. J Em Med 2011;40(1):53-7.
[2] Blaivas M, Theodoro D, Sierzinski PR. A study of bedside ocular ultrasonography in the emergency department. Acad Emerg Med 2002;9(8):791-9. [3] Kimberly HH, Shah S, Marill K, Noble V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 2008;15(2):201-4. [4] Wu EH, Fagan MJ, Reinert SE, Diaz JA. Self-confidence and perceived utility of the physical examination: a comparison of medical students, residents, and faculty internists. J Gen Intern Med 2007;22(12):1725-30. [5] Roberts E, Morgan R, King D, Clerkin L. Funduscopy: a forgotten art? Postgrad Med J 1999;75:282-4. [6] Bruce B, Lamirel C, Wright D, et al. Nonmydriatic ocular fundus photography in the emergency department. N Engl J Med 2011;364(4): 387-8. [7] Soldatos T, Karakitsos D, Chatzimichail K, Papathanasiou M, Gouliamos A, Karabanis A. Optic nerve sonography in the diagnosis evaluation of adult brain injury. Crit Care 2008;12(3). [8] Tayal VS, Neulander M, Norton HJ, et al. Emergency department sonographic measurement of optic nerve sheath diameter to detect findings of increased intracranial pressure in adult head injury patients. Ann Emerg Med 2007;49(4):508-14. [9] Tsung JW, Blaivas M, Cooper A, Levick NR. A rapid noninvasive method of detecting elevated intracranial pressure using bedside ocular ultrasound: application to 3 cases of head trauma in the pediatric emergency department. Ped Emer Care 2005;21(2):94-7. [10] Stone MB. Case report: ultrasound diagnosis of papilledema and increased intracranial pressure in pseudotumor cerebri. Am J Em Med 2009;27(3):376.e1-2. [11] Blehar DJ, Gaspari RJ, Montoya A, Calderon R. Correlation of visual axis measurements of the optic nerve sheath diameter. J Ultrasound Med 2008;27:407-11. [12] Copetti R, Cattarossi L. Optic nerve ultrasound: artifacts and real images. Intensive Care Med 2009;35(8):1488-9. [13] Tamburelli C, Salgarello T, Caputo CG, Giudiceandrea A, Scullica L. Ultrasonographic evaluation of optic disc swelling: comparison with CSLO in idiopathic intracranial hypertension. IOVS 2000;41(10): 2960-6.
www.elsevier.com/locate/ajem
Case Report Ultrasound assessment of optic disc edema in patients with headache Abstract Point-of-care ocular ultrasonography is emerging as a powerful tool to evaluate emergency department (ED) patients at risk for ophthalmologic and intracranial pathology. We present cases of 3 patients in whom optic disc swelling was identified using ocular ultrasound. Causes for optic disc swelling in our patients included idiopathic intracranial hypertension, secondary syphilis, and malignant hypertension with associated hypertensive retinopathy. Because direct visualization of the optic disc may be challenging in an ED setting, ultrasound examination of the optic disc may represent an important adjunct to fundoscopy when assessing patients with headache or visual complaints. Point-of-care ocular ultrasonography is emerging as a useful tool for the evaluation of patients at risk for ophthalmologic and intracranial pathology. Emergency physician–performed sonography appears to be a sensitive screening test for various ocular conditions including traumatic injuries, retinal vascular insult, and retinal detachment [1,2]. In addition, measurement of the retrobulbar optic nerve sheath diameter (ONSD) has been investigated as a means of noninvasively assessing intracranial pressure [2,3]. To date, however, little data exist on the performance of point-of-care sonography to assess swelling to the optic disc. Although direct visualization using an ophthalmoscope is considered the standard method of assessing the appearance of the fundus, it may be difficult or impossible to perform this effectively, especially in an ED setting [4-6]. Because optic disc swelling is always abnormal, a reliable method to assess patients at risk for this condition is of critical importance to the emergency physician. Below, we describe 3 cases in which point-of-care ultrasound was used to accurately identify optic disc edema in emergency department (ED) patients with various underlying diagnoses. The patient lies supine with the head in neutral position and is instructed to close both eyes. A small amount of ultrasound gel is placed over the closed eyelid, or a nonadhesive clear dressing may be placed over the eyelid to 0735-6757/$ – see front matter © 2012 Elsevier Inc. All rights reserved.
protect the eye from the gel. A high-frequency (10-13 MHz) linear array transducer with a Sonosite M-Turbo (Bothell, WA) is placed lightly on the lid. We recommend that the operator's fingers be braced on the bridge of the nose or forehead to minimize pressure on the globe (Fig. 1). The patient is instructed to look straight ahead, and the globe is scanned in the axial plane until a clear image of the optic disc is obtained. When the optic disc is isolated, it should be measured from its base to maximal height (Fig. 2A, normal landmarks). A 19-year-old woman was sent to the ED by her ophthalmologist for evaluation of persistent headache and decreasing peripheral vision. She reported approximately 6 months of gradually worsening blurry vision and diffuse headache associated with nausea. She had no additional medical problems and denied alcohol, tobacco, and drug use. On the day of presentation, she saw her ophthalmologist who noted bilateral optic disc swelling on examination and referred her to the ED for further evaluation. On evaluation, the patient's vital signs were normal. Her physical examination was notable for morbid obesity and bilateral optic disc swelling on fundoscopy (Fig. 3). Her visual acuity and visual fields were normal. An ocular ultrasound demonstrated significant swelling of bilateral optic discs (Fig. 2C, papilledema in idiopathic intracranial hypertension retinal base (thick arrow) with swollen optic disc [thin arrow]). A computed tomographic scan of her head
Fig. 1
Recommended technique for ocular ultrasound.
1654.e2
Case Report
Fig. 2 A, Normal ocular ultrasound landmarks; B, Hypertensive ischemic papillitis with retinal base [thick arrow] and swollen optic disc [thin arrow]; C, Papilledema in idiopathic intracranial hypertension with retinal base [thick arrow] and swollen optic disc [thin arrow]; D, Neurosyphilis induced optic disc swelling with height measurement.
showed no abnormalities. A lumbar puncture was performed in the ED. The opening pressure was markedly elevated at 51 cm, but analysis of the cerebrospinal fluid analysis was otherwise normal. Her symptoms significantly resolved after the procedure. Of note, however, her optic disc swelling persisted when she was evaluated with a repeat bedside sonogram 24 hours later, a finding that reflects the underlying pathophysiology of papilledema as a consequence of impairment of retrograde axoplasmic transport within the
Fig. 3 Fundoscopy of optic disc edema demonstrating blurred disc margins.
optic nerve rather than a direct result of the hydrostatic pressure of the cerebrospinal fluid (CSF) on the nerve head. The patient was diagnosed with idiopathic intracranial hypertension (IIH) and admitted to the hospital for further management. Her pain was controlled, and she was started on acetazolamide and topiramate. Her headache symptoms improved, and on follow-up with her ophthalmologist 3 months later, her papilledema had entirely resolved. A 36-year-old man with no prior medical history was transferred to our ED from a community clinic to be evaluated for hypertension. He reported several weeks of headache and blurry vision and had a blood pressure of 235/ 140 at triage. He denied chest pain, shortness of breath, or other symptoms. He smoked cigarettes and drank alcohol occasionally but denied illicit drug use. On further evaluation, a repeat blood pressure measurement remained elevated at 198/131, but vital signs were otherwise normal. His physical examination was unremarkable with the exception of bilateral optic disc swelling noted on fundoscopy. Ocular ultrasound demonstrated significant swelling of both optic Retinal base discs with the right eye more severely affected (Fig. 2B, [thick arrow] with swollen optic disc [thin arrow]). The patient was admitted to the hospital for blood pressure control. A subsequent noncontrast computed tomographic scan of the brain was unremarkable. The ophthalmology service evaluated the patient and confirmed examination findings consistent with severe hypertensive
Case Report retinopathy. The patient's blood pressure was controlled with intravenous and oral medications during his admission. He was ultimately discharged home on oral blood pressure agents but was lost to follow-up before further outpatient workup for his hypertension could be undertaken. A 41-year-old man with HIV was evaluated in our ED for 1 day of cloudiness and “darkening” of the peripheral vision in his right eye. He denied diplopia, flashing lights, floaters, headache, fevers, neck stiffness, focal weakness, or associated trauma. He had been diagnosed with HIV 3 years prior and had started antiretroviral therapy 6 weeks before the onset of his symptoms. He had no coexisting medical problems and denied tobacco, alcohol, and drug use. On initial evaluation in the ED, the patient's vital signs and general physical examination were normal. His visual acuity, visual fields, intraocular pressures, extraocular movements, and pupils were normal. No abnormalities were noted in the anterior segment of either eye; however, the optic discs were not well seen on initial evaluation in the ED. Point-of-care sonography revealed significant swelling of both optic discs. The findings were more severe in the right eye in which the apex of the disc was noted to bulge anteriorly approximately 1.5 mm relative to the surface of the retina (Fig. 2D). A subsequent magnetic resonance imaging confirmed bilateral optic disc edema, but no abnormal findings were noted in the brain. A lumbar puncture yielded spinal fluid containing 10 white blood cells per high-power field, 15 red blood cells per high-power field, glucose of 52, and total protein of 57. The opening pressure was normal at 14 cm. Serum and CSF cryptococcal antigen tests were negative. The gram stain and bacterial culture of the CSF were both negative; however, CSF Venereal Disease Research Laboratory test as well as serum rapid plasma reagin (titer 256:1) and serum treponemal antibody tests were positive. The patient was diagnosed with neurosyphilis with associated papillitis. He was treated with a 5-week course of penicillin. On follow-up with neurology and ophthalmology, the patient had no further symptoms and was noted to have resolution of the optic disc swelling in both eyes. As the cases above illustrate, point-of-care ocular ultrasonography can be a useful diagnostic tool for assessing swelling of the optic disc from a variety of causes. In an ED setting, numerous obstacles may prevent an accurate assessment of the appearance of the optic disc using a traditional ophthalmoscope. Thus, we believe that the technique described above may prove to be a valuable adjunct to the standard ocular examination. A rich differential diagnosis exists for the underlying causes of optic disc edema; however, of greatest clinical importance to the emergency physician is the ability to detect elevated intracranial pressure (ICP), either from an intracranial mass lesion or from IIH. The presence of disc swelling demands prompt subsequent evaluation, usually with neuroimaging and a lumbar puncture. When optic disc swelling is bilateral and caused by elevated ICP, it is correctly termed papilledema. As
1654.e3 illustrated above, disc edema can result from other causes as well, specifically ischemia caused by malignant hypertension, inflammation caused by conditions such as sarcoidosis or multiple sclerosis, or with infections such as neurosyphilis. In these cases, the disc edema is referred to as “papillitis.” If no evidence of elevated ICP is uncovered, a search for one of these underlying etiologies should be undertaken. What is the relationship between the presence of optic disc swelling and the diameter of the retrobulbar optic nerve sheath? Current literature in traumatic brain injury indicates that ONSD of 5.7 to 6 mm is accurate in predicting elevated ICP in both the intensive care unit setting [7] and in the ED screening [8,9], although these findings did not attempt to characterize the appearance of the optic disc. One prospective ED and intensive care unit study compared ultrasound ONSD measurements and invasive ICP monitoring, showing that an ONSD of greater than 5 mm correlated to an ICP greater than 20 mm Hg [3]. One prior ED case report describes nerve sheath enlargement (ONSDs of 6.9 and 7.1 mm) in addition to visible optic disc bulging in a patient with significantly elevated ICP due to idiopathic intracranial hypertension, suggesting a possible relationship [10]. It should be mentioned, however, that controversy exists as to the reliability of the technique used to measure the ONSD in these studies [11,12]. Thus, any relationship between sonographic measurements of ONSD and the presence of optic disc swelling remains an open question. One final point deserved mention: The degree of swelling visualized on bedside sonography that represents true underlying pathology has yet to be determined. Our clinical experience suggests that the optic disc is visible in many healthy patients but appears significantly smaller than in any patients described present. We recommend that any significant degree of disc swelling be further referred for expert evaluation if uncertainty exists, although literature in the ophthalmologic journals suggests that ultrasonographic measurements may accurately assess the presence of optic disc swelling when compared with the criterion standard of measurement, confocal scanning laser ophthalmoscope measurements [13]. Bedside ultrasonography appears to be a promising modality to improve clinical examination skills in evaluating ocular pathology in the ED. More study is needed to determine physician accuracy and test characteristics of bedside ultrasound in detecting optic disc swelling. However, because direct visualization of the optic disc may be challenging in an ED setting, ultrasound examination of the optic disc may represent an important adjunct to fundoscopy when assessing patients with headache or visual complaints. Siri Daulaire MD Department of Emergency Medicine Rhode Island Hospital Providence, RI E-mail address: [email protected]
1654.e4
Case Report Lauren Fine MD Department of Emergency Medicine Alameda County Medical Center Oakland, CA
Margaret Salmon MD Department of Emergency Medicine University of California at San Francisco Medical Center San Francisco, CA Catherine Cummings MD Otto Liebmann MD Department of Emergency Medicine Rhode Island Hospital Providence, RI Sachita Shah MD, RDMS Division of Emergency Medicine Harborview Medical Center Seattle, WA Nathan Teismann MD Department of Emergency Medicine University of California at San Francisco Medical Center San Francisco, CA doi:10.1016/j.ajem.2011.06.030
References [1] Shinar Z, Chan L, Orlinsky M. Use of ocular ultrasound for the evaluation of retinal detachment. J Em Med 2011;40(1):53-7.
[2] Blaivas M, Theodoro D, Sierzinski PR. A study of bedside ocular ultrasonography in the emergency department. Acad Emerg Med 2002;9(8):791-9. [3] Kimberly HH, Shah S, Marill K, Noble V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 2008;15(2):201-4. [4] Wu EH, Fagan MJ, Reinert SE, Diaz JA. Self-confidence and perceived utility of the physical examination: a comparison of medical students, residents, and faculty internists. J Gen Intern Med 2007;22(12):1725-30. [5] Roberts E, Morgan R, King D, Clerkin L. Funduscopy: a forgotten art? Postgrad Med J 1999;75:282-4. [6] Bruce B, Lamirel C, Wright D, et al. Nonmydriatic ocular fundus photography in the emergency department. N Engl J Med 2011;364(4): 387-8. [7] Soldatos T, Karakitsos D, Chatzimichail K, Papathanasiou M, Gouliamos A, Karabanis A. Optic nerve sonography in the diagnosis evaluation of adult brain injury. Crit Care 2008;12(3). [8] Tayal VS, Neulander M, Norton HJ, et al. Emergency department sonographic measurement of optic nerve sheath diameter to detect findings of increased intracranial pressure in adult head injury patients. Ann Emerg Med 2007;49(4):508-14. [9] Tsung JW, Blaivas M, Cooper A, Levick NR. A rapid noninvasive method of detecting elevated intracranial pressure using bedside ocular ultrasound: application to 3 cases of head trauma in the pediatric emergency department. Ped Emer Care 2005;21(2):94-7. [10] Stone MB. Case report: ultrasound diagnosis of papilledema and increased intracranial pressure in pseudotumor cerebri. Am J Em Med 2009;27(3):376.e1-2. [11] Blehar DJ, Gaspari RJ, Montoya A, Calderon R. Correlation of visual axis measurements of the optic nerve sheath diameter. J Ultrasound Med 2008;27:407-11. [12] Copetti R, Cattarossi L. Optic nerve ultrasound: artifacts and real images. Intensive Care Med 2009;35(8):1488-9. [13] Tamburelli C, Salgarello T, Caputo CG, Giudiceandrea A, Scullica L. Ultrasonographic evaluation of optic disc swelling: comparison with CSLO in idiopathic intracranial hypertension. IOVS 2000;41(10): 2960-6.