Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2008
Background:Optical coherence tomography (OCT) - measured retinal nerve fiber layer (RNFL) values ... more Background:Optical coherence tomography (OCT) - measured retinal nerve fiber layer (RNFL) values may represent a surrogate biomarker for axonal integrity in multiple sclerosis (MS). The purpose of this study was to determine whether RNFL measurements obtained within two years of an optic neuritis (ON) event distinguish patients at increased risk of developing clinically-definite MS (CDMS).Methods:Fifty consecutively sampled patients who experienced a single ON event were followed prospectively for a mean period of 34 months with OCT testing. Values of RNFL in clinically-affected and non-affected eyes were compared between patients who developed CDMS and those that did not develop MS after ON.Findings:Twenty-one patients (42%) developed CDMS during the course of the study, with a mean conversion time of 27 months. Mean RNFL values were thinner in the clinically - affected eyes of non - MS patients than CDMS eyes after one year (p = 0.0462) due to more severe ON events in the former. ...
Graefe's Archive for Clinical and Experimental Ophthalmology, 1998
The relative afferent papillary defect (RAPD) is an important parameter for quantifying the loss ... more The relative afferent papillary defect (RAPD) is an important parameter for quantifying the loss of neuronal function in asymmetric optic nerve disease. We wanted to assess its correlation with retinal ganglion cell loss, estimated from visual field defects, using a recently described method. In 36 patients with unilateral optic nerve disease, the RAPD was measured using an automated, computerized infrared pupillometer. The percentage of ganglion cell loss was estimated with clear templates. We found a highly significant correlation between the RAPD and estimated ganglion cell loss. The correlation was higher for Humphrey visual fields than for Goldmann visual fields measured with the 14e and 12e stimulus. The RAPD correlates well with estimated retinal ganglion cell loss in optic nerve disease. Humphrey visual fields seem to reflect the ganglion cell loss better than Goldmann visual fields. The spatial distribution of pupillomotor retinal ganglion cells seems to be proportional to the distribution of light-sensitive ganglion cells projecting to the lateral geniculate nucleus.
BackgroundPhotophobia is a potentially debilitating symptom often found in dry eye disease (DE), ... more BackgroundPhotophobia is a potentially debilitating symptom often found in dry eye disease (DE), migraine and traumatic brain injury (TBI).MethodsWe conducted a review of the literature via a PubMed search of English language articles with a focus on how photophobia may relate to a shared pathophysiology across DE, migraine and TBI.ResultsDE, migraine and TBI are common conditions in the general population, are often comorbid, and share photophobia as a symptom. Across the three conditions, neural dysregulation of peripheral and central nervous system components is implicated in photophobia in various animal models and in humans. Enhanced activity of the neuropeptide calcitonin gene-related peptide (CGRP) is closely linked to photophobia. Current therapies for photophobia include glasses which shield the eyes from specific wavelengths, botulinum toxin, and inhibition of CGRP and its receptor. Many individuals have persistent photophobia despite the use of these therapies, and thus, ...
To examine whether herpes zoster antigen (also called varicella-zoster virus antigen) was detecta... more To examine whether herpes zoster antigen (also called varicella-zoster virus antigen) was detectable in temporal artery biopsies taken from individuals with giant cell arteritis (GCA). Retrospective comparative case series. Sections of formalin-fixed paraffin-embedded temporal arteries were examined first by hematoxylin-eosin (H&E) staining to establish the diagnosis of GCA. Adjacent sections of the same biopsy were then examined by immunohistochemistry, using 2 different monoclonal antibodies against a major antigen of varicella-zoster virus called gE. Pathologic specimens were obtained from patients cared for at the University of Iowa and Washington University in St. Louis ophthalmology clinics. The study included biopsies from 25 patients with symptoms of GCA as well as positive H&E pathology and 25 patients with symptoms compatible with GCA but negative H&E pathology. Among the GCA-positive group, 3 patients had positive staining for herpes zoster antigen. Among the GCA-negative...
Journal of the neurological sciences, Jan 15, 2018
The Pulfrich phenomenon (PF) is the illusory perception that an object moving linearly along a 2-... more The Pulfrich phenomenon (PF) is the illusory perception that an object moving linearly along a 2-D plane appears to instead follow an elliptical 3-D trajectory, a consequence of inter-eye asymmetry in the timing of visual object identification in the visual cortex; with optic neuritis as a common etiology. We have designed an objective method to identify the presence and magnitude of the PF, in conjunction with a cooresponding strategy by which to abolish the effect; with monocular application of neutral density filters to the less affected fellow eye, in patients with MS and a history of optic neuropathy (e.g. related to acute optic neuritis or subclinical optic neuropathy). Twenty-three MS patients with a history of acute unilateral or bilateral optic neuritis, and ten healthy control subjects (HC) were recruited to participate in a pilot study to assess our strategy. Subjects were asked to indicate whether a linearly moving pendulum ball followed a linear 2-D path versus an illus...
Precise measurements of visual fixation and its instability were recorded during optical coherenc... more Precise measurements of visual fixation and its instability were recorded during optical coherence tomography (OCT) as a marker of neural network dysfunction in multiple sclerosis (MS), which could be used to monitor disease progression or response to treatment. A total of 16 MS patients and 26 normal subjects underwent 30 seconds of scanning laser ophthalmoscope (SLO)-based eye tracking during OCT scanning of retinal layer thickness. Study groups consisted of normal eyes, MS eyes without prior optic neuritis (MS wo ON), and MS eyes with prior optic neuritis (MS + ON). Kernel density estimation quantified fixation instability from the distribution of fixation points on the retina. In MS wo ON eyes, fixation instability was compared to other measures of visual and neurologic function. Fixation instability was increased in MS wo ON eyes (0.062 deg2) compared to normal eyes (0.030 deg2, P = 0.015). A further increase was seen for MS + ON eyes (0.11 deg2) compared to MS wo ON (P = 0.04)...
Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2008
Background:Optical coherence tomography (OCT) - measured retinal nerve fiber layer (RNFL) values ... more Background:Optical coherence tomography (OCT) - measured retinal nerve fiber layer (RNFL) values may represent a surrogate biomarker for axonal integrity in multiple sclerosis (MS). The purpose of this study was to determine whether RNFL measurements obtained within two years of an optic neuritis (ON) event distinguish patients at increased risk of developing clinically-definite MS (CDMS).Methods:Fifty consecutively sampled patients who experienced a single ON event were followed prospectively for a mean period of 34 months with OCT testing. Values of RNFL in clinically-affected and non-affected eyes were compared between patients who developed CDMS and those that did not develop MS after ON.Findings:Twenty-one patients (42%) developed CDMS during the course of the study, with a mean conversion time of 27 months. Mean RNFL values were thinner in the clinically - affected eyes of non - MS patients than CDMS eyes after one year (p = 0.0462) due to more severe ON events in the former. ...
Graefe's Archive for Clinical and Experimental Ophthalmology, 1998
The relative afferent papillary defect (RAPD) is an important parameter for quantifying the loss ... more The relative afferent papillary defect (RAPD) is an important parameter for quantifying the loss of neuronal function in asymmetric optic nerve disease. We wanted to assess its correlation with retinal ganglion cell loss, estimated from visual field defects, using a recently described method. In 36 patients with unilateral optic nerve disease, the RAPD was measured using an automated, computerized infrared pupillometer. The percentage of ganglion cell loss was estimated with clear templates. We found a highly significant correlation between the RAPD and estimated ganglion cell loss. The correlation was higher for Humphrey visual fields than for Goldmann visual fields measured with the 14e and 12e stimulus. The RAPD correlates well with estimated retinal ganglion cell loss in optic nerve disease. Humphrey visual fields seem to reflect the ganglion cell loss better than Goldmann visual fields. The spatial distribution of pupillomotor retinal ganglion cells seems to be proportional to the distribution of light-sensitive ganglion cells projecting to the lateral geniculate nucleus.
BackgroundPhotophobia is a potentially debilitating symptom often found in dry eye disease (DE), ... more BackgroundPhotophobia is a potentially debilitating symptom often found in dry eye disease (DE), migraine and traumatic brain injury (TBI).MethodsWe conducted a review of the literature via a PubMed search of English language articles with a focus on how photophobia may relate to a shared pathophysiology across DE, migraine and TBI.ResultsDE, migraine and TBI are common conditions in the general population, are often comorbid, and share photophobia as a symptom. Across the three conditions, neural dysregulation of peripheral and central nervous system components is implicated in photophobia in various animal models and in humans. Enhanced activity of the neuropeptide calcitonin gene-related peptide (CGRP) is closely linked to photophobia. Current therapies for photophobia include glasses which shield the eyes from specific wavelengths, botulinum toxin, and inhibition of CGRP and its receptor. Many individuals have persistent photophobia despite the use of these therapies, and thus, ...
To examine whether herpes zoster antigen (also called varicella-zoster virus antigen) was detecta... more To examine whether herpes zoster antigen (also called varicella-zoster virus antigen) was detectable in temporal artery biopsies taken from individuals with giant cell arteritis (GCA). Retrospective comparative case series. Sections of formalin-fixed paraffin-embedded temporal arteries were examined first by hematoxylin-eosin (H&E) staining to establish the diagnosis of GCA. Adjacent sections of the same biopsy were then examined by immunohistochemistry, using 2 different monoclonal antibodies against a major antigen of varicella-zoster virus called gE. Pathologic specimens were obtained from patients cared for at the University of Iowa and Washington University in St. Louis ophthalmology clinics. The study included biopsies from 25 patients with symptoms of GCA as well as positive H&E pathology and 25 patients with symptoms compatible with GCA but negative H&E pathology. Among the GCA-positive group, 3 patients had positive staining for herpes zoster antigen. Among the GCA-negative...
Journal of the neurological sciences, Jan 15, 2018
The Pulfrich phenomenon (PF) is the illusory perception that an object moving linearly along a 2-... more The Pulfrich phenomenon (PF) is the illusory perception that an object moving linearly along a 2-D plane appears to instead follow an elliptical 3-D trajectory, a consequence of inter-eye asymmetry in the timing of visual object identification in the visual cortex; with optic neuritis as a common etiology. We have designed an objective method to identify the presence and magnitude of the PF, in conjunction with a cooresponding strategy by which to abolish the effect; with monocular application of neutral density filters to the less affected fellow eye, in patients with MS and a history of optic neuropathy (e.g. related to acute optic neuritis or subclinical optic neuropathy). Twenty-three MS patients with a history of acute unilateral or bilateral optic neuritis, and ten healthy control subjects (HC) were recruited to participate in a pilot study to assess our strategy. Subjects were asked to indicate whether a linearly moving pendulum ball followed a linear 2-D path versus an illus...
Precise measurements of visual fixation and its instability were recorded during optical coherenc... more Precise measurements of visual fixation and its instability were recorded during optical coherence tomography (OCT) as a marker of neural network dysfunction in multiple sclerosis (MS), which could be used to monitor disease progression or response to treatment. A total of 16 MS patients and 26 normal subjects underwent 30 seconds of scanning laser ophthalmoscope (SLO)-based eye tracking during OCT scanning of retinal layer thickness. Study groups consisted of normal eyes, MS eyes without prior optic neuritis (MS wo ON), and MS eyes with prior optic neuritis (MS + ON). Kernel density estimation quantified fixation instability from the distribution of fixation points on the retina. In MS wo ON eyes, fixation instability was compared to other measures of visual and neurologic function. Fixation instability was increased in MS wo ON eyes (0.062 deg2) compared to normal eyes (0.030 deg2, P = 0.015). A further increase was seen for MS + ON eyes (0.11 deg2) compared to MS wo ON (P = 0.04)...
Uploads
Papers by Randy Kardon