Abstract Details

Title Neurology of Eye Movements of the Blind

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P02 - (-)

Poster/Presentation
Number 247

Objective

Background BACKGROUND: Binocular visual loss (VL) causes gaze instability and nystagmus. Monocular VL causes vertical oscillations of the affected eye: the Heimann-Bielschowsky phenomenon. No neural substrate has been identified to account for these findings.

Design/Methods DESIGN/METHODS: We measured (search coils) eye movements of (A) six patients with monocular VL(1 F; ages 29-83 yrs), due to ocular trauma (2), congenital cataract (1) hypothalamic tumor (1), age-related macular degeneration (ARMD - 2); (B) two patients with binocular VL: 25-yr-old woman with Leber congenital amaurosis (LCA) and 60-yr-old man self-poisoned with methanol; (C) 20 control subjects (CS) (8 female; age range 25-72 yrs). Fixation stability and saccades were tested using their thumbs as cues if VL was complete. We computed standard deviation (SD) of 3-D eye position (gaze) during attempted fixation.

Results RESULTS: CS showed similar gaze stability of covered and viewing eyes; SD gaze < 0.18[deg]in all directions. During binocular viewing, patients with VL before 18 yrs showed increased (p<0.05)SD of vertical gaze in the eye with visual loss and, to a lesser extent, in the normal eye. If the good eye was covered, gaze stability of the visually impaired eye improved; sometimes, gaze stability deteriorated in the good eye under cover. Gaze stability was similar in ARMD to controls. Patients with binocular VL showed larger (p<0.01), disconjugate drifts than CS or monocular VL patients, with drifting "null" positions. Patients made conjugate upward saccades except for LCA patient, who lacked voluntary eye control.

Conclusions CONCLUSIONS: In health, gaze stability (conjugate and monocular) depends on a neural network that integrates premotor signals, such as saccades, and generates a stable eye position signal. Visual loss deprives this network of inputs necessary to optimize its performance so that the stability and conjugacy of gaze are disrupted.

Authors/Disclosures
R. John Leigh, MD PRESENTER	No disclosure on file
	No disclosure on file
Sylvia C. Kurz, MD, PhD (Yale University School of Medicine)	Dr. Kurz has received personal compensation in the range of $0-$499 for serving as a Consultant for Advanced Accelerator Applications.
Norah S. Lincoff, MD (Buffalo General Hospital)	Dr. Lincoff has nothing to disclose.
Matthew J. Thurtell, MD (University of Iowa)	Dr. Thurtell has received publishing royalties from a publication relating to health care.
Edward Fox, MD, PhD, FAAN	Dr. Fox has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion Pharmaceuticals. Dr. Fox has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. Dr. Fox has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biogen. Dr. Fox has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for EMD Serono. Dr. Fox has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for GW Pharmaceuticals. Dr. Fox has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for TG Therapeutics. Dr. Fox has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Bristol Myers Squibb. Dr. Fox has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Fox has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Fox has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Alexion. Dr. Fox has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Biogen. Dr. Fox has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Genentech. Dr. Fox has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Bristol Myers Squibb. The institution of Dr. Fox has received research support from Biogen. The institution of Dr. Fox has received research support from Genentech. The institution of Dr. Fox has received research support from Celgene - BMS. The institution of Dr. Fox has received research support from Chugai. The institution of Dr. Fox has received research support from Novartis. The institution of Dr. Fox has received research support from EMD-Serono. The institution of Dr. Fox has received research support from TG Therapeutics. The institution of Dr. Fox has received research support from AbbVie. The institution of Dr. Fox has received research support from Sanofi Genzyme. The institution of Dr. Fox has received research support from AbbVie.
	No disclosure on file

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