The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Robert C Walls - One of the best experts on this subject based on the ideXlab platform.

  • effect of light on the prevalence of simple Anisocoria
    Ophthalmology, 1996
    Co-Authors: Byron L Lam, Stanley H Thompson, Robert C Walls
    Abstract:

    Abstract Purpose: Because simple Anisocoria is believed to decrease in bright light, the authors determined the prevalence of simple Anisocoria under different lighting conditions. Methods: The authors measured the pupil size of 104 healthy subjects with infrared videography at four clinically accessible light levels: darkness; darkness with a hand-held light shining from below; room light; and room light with the hand light shining from below. Results: Of the 104 subjects, 40 (38%) were men and 64 (62%) were women. The ages ranged from 12 to 71 years (mean, 36.3 ± 12.5 years). The mean decrease in pupillary diameter from darkness to the brightest condition was 1.89 mm. Based on the traditional definition of a pupillary diameter difference of 0.4 mm or greater, the prevalence of simple Anisocoria decreased from 18% in darkness to 8% in room light with the hand-held light shining from below. The prevalence of Anisocoria varied considerably when other definitions were used. Repeated measures analysis of variance showed that pupillary area difference decreased with brighter conditions ( P = 0.026). However, the ratio of the pupillary areas did not change with brighter conditions ( P = 0.666). Conclusions: The prevalence of simple Anisocoria decreases with brighter conditions based on pupillary diameter difference. However, this decrease is not apparent when Anisocoria is expressed as pupillary area ratio. Those clinicians who measure pupils will find that simple Anisocoria decreases in bright light. However, with gross observation where perception of an Anisocoria may be related more to the ratio of the pupillary areas, simple Anisocoria may not seem to change much with brighter conditions.

Randy H Kardon - One of the best experts on this subject based on the ideXlab platform.

  • Buzzing Sympathetic Nerves: A New Test to Enhance Anisocoria in Horner's Syndrome
    Frontiers Media S.A., 2019
    Co-Authors: Rawan Omary, Randy H Kardon, Christopher J. Bockisch, Klara Landau, Konrad P. Weber
    Abstract:

    Introduction: Patients with suspected Horner's syndrome having equivocal pupil dilation lag and pharmacologic testing may undergo unnecessary MR imaging and work up in the case of false positive pupil test results. Our goal was to increase the diagnostic accuracy of pupillometry by accentuating the inter-ocular asymmetry of sympathetic innervation to the iris dilator with surface electrical stimulation of the median nerve using a standard electromyography machine. We hypothesized that an accentuated difference in sympathetic response between the two eyes would facilitate the diagnosis of Horner's syndrome.Methods: Eighteen patients with pharmacologically proven Horner's syndrome were compared to ten healthy volunteers tested before and after monocular instillation of 0.2% brimonidine tartrate ophthalmic solution to induce pharmacological Horner's syndrome. Pupillary responses were measured with binocular pupillometry in response to sympathetic activation by electrical stimulation of the median nerve in darkness and at various times after extinction of a light stimulus. Sudomotor sympathetic responses from the palm of the stimulated arm were recorded simultaneously.Results: In subjects with Horner's syndrome and pharmacologically induced unilateral sympathetic deficit, electrical stimulation in combination with the extinction of light greatly enhanced the Anisocoria during the evoked pupil dilation, while there was no significant increase in Anisocoria in healthy subjects. The asymmetry of the sympathetic response was greatest when the electrical stimulus was given 2 s after termination of the light or under constant low light conditions. When given 2 s after termination of light, the electrical stimulation increased the mean Anisocoria from 1.0 to 1.2 mm in Horner's syndrome (p = 0.01) compared to 0.22–0.26 mm in healthy subjects (p = 0.1). In all subjects, the maximal Anisocoria induced by the electrical stimulation appeared within a 2 s interval after the stimulus. Correspondingly, the largest change in Anisocoria between light and dark without electrical stimulation was seen between 3 and 4 s after light-off. While stronger triple stimulation further enhanced the Anisocoria, it was less well tolerated.Conclusions: Electrical stimulation 2 s after light-off greatly enhances the sensitivity of pupillometry for diagnosing Horner's syndrome. This new method may help to rule in or rule out a questionable Horner's syndrome, especially if the results of topical pharmacological testing are inconclusive

  • Video_5_Buzzing Sympathetic Nerves: A New Test to Enhance Anisocoria in Horner's Syndrome.MP4
    2019
    Co-Authors: Rawan Omary, Randy H Kardon, Christopher J. Bockisch, Klara Landau, Konrad P. Weber
    Abstract:

    Introduction: Patients with suspected Horner's syndrome having equivocal pupil dilation lag and pharmacologic testing may undergo unnecessary MR imaging and work up in the case of false positive pupil test results. Our goal was to increase the diagnostic accuracy of pupillometry by accentuating the inter-ocular asymmetry of sympathetic innervation to the iris dilator with surface electrical stimulation of the median nerve using a standard electromyography machine. We hypothesized that an accentuated difference in sympathetic response between the two eyes would facilitate the diagnosis of Horner's syndrome.Methods: Eighteen patients with pharmacologically proven Horner's syndrome were compared to ten healthy volunteers tested before and after monocular instillation of 0.2% brimonidine tartrate ophthalmic solution to induce pharmacological Horner's syndrome. Pupillary responses were measured with binocular pupillometry in response to sympathetic activation by electrical stimulation of the median nerve in darkness and at various times after extinction of a light stimulus. Sudomotor sympathetic responses from the palm of the stimulated arm were recorded simultaneously.Results: In subjects with Horner's syndrome and pharmacologically induced unilateral sympathetic deficit, electrical stimulation in combination with the extinction of light greatly enhanced the Anisocoria during the evoked pupil dilation, while there was no significant increase in Anisocoria in healthy subjects. The asymmetry of the sympathetic response was greatest when the electrical stimulus was given 2 s after termination of the light or under constant low light conditions. When given 2 s after termination of light, the electrical stimulation increased the mean Anisocoria from 1.0 to 1.2 mm in Horner's syndrome (p = 0.01) compared to 0.22–0.26 mm in healthy subjects (p = 0.1). In all subjects, the maximal Anisocoria induced by the electrical stimulation appeared within a 2 s interval after the stimulus. Correspondingly, the largest change in Anisocoria between light and dark without electrical stimulation was seen between 3 and 4 s after light-off. While stronger triple stimulation further enhanced the Anisocoria, it was less well tolerated.Conclusions: Electrical stimulation 2 s after light-off greatly enhances the sensitivity of pupillometry for diagnosing Horner's syndrome. This new method may help to rule in or rule out a questionable Horner's syndrome, especially if the results of topical pharmacological testing are inconclusive.

  • unilateral periodic pupillary constriction causing alternating Anisocoria
    Neurology, 2018
    Co-Authors: Erin C Conrad, Randy H Kardon, Imran Jivraj, Grant T Liu
    Abstract:

    A 16-year-old boy with attention deficit disorder (ADD) presented to our pediatric neuro-ophthalmology clinic with 2 years of alternating pupil asymmetry. MRI of the brain, spine, and chest and magnetic resonance angiography of the brain were normal. He had longstanding intermittent mild bilateral headaches (but no migraines) and 3 years of amplified musculoskeletal pain syndrome localized to the abdomen. He took lisdexamfetamine for ADD but used no other oral or topical ocular medications.

  • brief transient horner s syndrome can be the hallmark of a carotid artery dissection
    Neurology, 1998
    Co-Authors: Enrique C Leira, Birgitte H Bendixen, Randy H Kardon, Harold P Adams
    Abstract:

    We describe a 41-year-old woman in whom the diagnosis of carotid artery dissection was suspected based on a recent history of Anisocoria and ipsilateral ptosis that lasted 2 days. She had a normal neurologic examination, including no clinical evidence of Anisocoria or ptosis. Subsequently, a cocaine test demonstrated pharmacologic Horner's syndrome. MRI confirmed the carotid dissection. This patient illustrates that a history of transient pupillary and eyelid abnormalities can lead to the diagnosis of a carotid dissection. Specific questioning about transient Anisocoria and ptosis should be considered when a carotid artery dissection is suspected. Pharmacologic testing may be a useful tool in such instances.

Byron L Lam - One of the best experts on this subject based on the ideXlab platform.

  • an Anisocoria produces a small relative afferent pupillary defect in the eye with the smaller pupil
    Journal of Neuro-ophthalmology, 1999
    Co-Authors: Byron L Lam, H S Thompson
    Abstract:

    Objectives To determine whether an Anisocoria can produce a relative afferent pupillary defect of clinical importance. Material and methods Anisocoria and relative afferent pupillary defect were measured with infrared videography in three clinical experiments: 1) every few minutes in eight normal subjects who remained in darkness as one pupil was dilating from mydriatic drops; 2) every 2 hours, for 8 hours in six normal subjects who remained in room light after one pupil was dilated with mydriatic drops; and 3) before and after dilation of one pupil in 24 patients with known afferent defects from optic nerve disease and who remained in room light. Results In the presence of an Anisocoria, the relative afferent pupillary defect was almost always in the eye with the smaller pupil. The results of the three experiments were: 1) In darkness, the induced pupillary defect was found to be related to the ratio of the areas of the two pupils (R = 0.942), and 0.14 log unit of pupillary defect was produced in the eye with the smaller pupil for every millimeter of Anisocoria. 2) In room light, the induced pupillary defect was in the eye with the smaller pupil but was less than in Experiment 1 and persisted throughout the 8 hours. This was presumably because the eye with the larger pupil had become more light adapted in the clinic light than the eye with the smaller pupil. 3) In room light, inducing an Anisocoria in patients with preexisting afferent pupillary defect tended to shift the pupillary defect toward the eye with the smaller pupil (R = 0.68). Conclusions Clinically, approximately 0.1 log unit of relative afferent pupillary defect is produced in the eye with the smaller pupil for every millimeter of Anisocoria. Therefore, the Anisocoria must be larger than 2 mm in diameter difference to induce a clinically significant relative afferent pupillary defect.

  • effect of light on the prevalence of simple Anisocoria
    Ophthalmology, 1996
    Co-Authors: Byron L Lam, Stanley H Thompson, Robert C Walls
    Abstract:

    Abstract Purpose: Because simple Anisocoria is believed to decrease in bright light, the authors determined the prevalence of simple Anisocoria under different lighting conditions. Methods: The authors measured the pupil size of 104 healthy subjects with infrared videography at four clinically accessible light levels: darkness; darkness with a hand-held light shining from below; room light; and room light with the hand light shining from below. Results: Of the 104 subjects, 40 (38%) were men and 64 (62%) were women. The ages ranged from 12 to 71 years (mean, 36.3 ± 12.5 years). The mean decrease in pupillary diameter from darkness to the brightest condition was 1.89 mm. Based on the traditional definition of a pupillary diameter difference of 0.4 mm or greater, the prevalence of simple Anisocoria decreased from 18% in darkness to 8% in room light with the hand-held light shining from below. The prevalence of Anisocoria varied considerably when other definitions were used. Repeated measures analysis of variance showed that pupillary area difference decreased with brighter conditions ( P = 0.026). However, the ratio of the pupillary areas did not change with brighter conditions ( P = 0.666). Conclusions: The prevalence of simple Anisocoria decreases with brighter conditions based on pupillary diameter difference. However, this decrease is not apparent when Anisocoria is expressed as pupillary area ratio. Those clinicians who measure pupils will find that simple Anisocoria decreases in bright light. However, with gross observation where perception of an Anisocoria may be related more to the ratio of the pupillary areas, simple Anisocoria may not seem to change much with brighter conditions.

Nader D. Nader - One of the best experts on this subject based on the ideXlab platform.

  • Postoperative Anisocoria in a patient undergoing endoscopic sinus surgery.
    Regional anesthesia and pain medicine, 1999
    Co-Authors: David T.r. Stewart, George T. Simpson, Nader D. Nader
    Abstract:

    Abstract Objective . Anisocoria after sinus surgery can be related to serious complications such as intraorbital hematoma or increased intracranial pressure secondary to an expanding hematoma. Case report . A 51-year-old man underwent endoscopic surgery of sinuses, and developed Anisocoria; likely a result of the local spread of cocaine used to provide local anesthesia and vasoconstriction. The localized effect of this anesthetic agent produced a typical picture of nasociliary ganglion block that subsided in a few hours. In the results, the nasociliary nerve block was noticed on recovery from anesthesia with no other neurologic deficit. Ophthalmologic examination demonstrated a short-lasting Anisocoria with loss of accommodation and sensory block over the tip of the nose. Conclusion . The central spread of the local anesthetics should be considered as a differential diagnosis of unexplained Anisocoria, especially when it is associated with loss of corneal reflex.

Maria Teresa Dotti - One of the best experts on this subject based on the ideXlab platform.

  • temporal lobe abnormalities in neurosyphilis
    Practical Neurology, 2014
    Co-Authors: Andrea Mignarri, Umberto Arrigucci, Piero Coleschi, Roberta Bilenchi, Antonio Federico, Maria Teresa Dotti
    Abstract:

    A 28-year-old woman presented with a 5-month history of cognitive and behavioural disturbances. Her past history was unremarkable, and she had no family history of neurological disorders. On examination, she showed temporospatial disorientation, ideomotor apraxia, gait ataxia, dysarthria, Anisocoria and reduced pupillary light responses. Routine blood tests were normal. MR scan of brain showed T2/FLAIR temporal hyperintensities (figure 1). Cerebrospinal fluid (CSF) analysis showed …