Deformation of Optic Nerve Head and Peripapillary Tissues by Horizontal Duction

Melinda Y Chang; Andrew Shin; Joseph Park; Aaron Nagiel; Robert A Lalane; Steven D Schwartz; Joseph L Demer

doi:10.1016/j.ajo.2016.10.001

Deformation of Optic Nerve Head and Peripapillary Tissues by Horizontal Duction

Am J Ophthalmol. 2017 Feb:174:85-94. doi: 10.1016/j.ajo.2016.10.001. Epub 2016 Oct 15.

Authors

Melinda Y Chang¹, Andrew Shin¹, Joseph Park¹, Aaron Nagiel¹, Robert A Lalane¹, Steven D Schwartz¹, Joseph L Demer²

Affiliations

¹ Department of Ophthalmology, David Geffen Medical School at University of California, Los Angeles, California; Stein Eye Institute, David Geffen Medical School at University of California, Los Angeles, California.
² Department of Ophthalmology, David Geffen Medical School at University of California, Los Angeles, California; Stein Eye Institute, David Geffen Medical School at University of California, Los Angeles, California; Department of Neurology, David Geffen Medical School at University of California, Los Angeles, California; Neuroscience, David Geffen Medical School at University of California, Los Angeles, California; Bioengineering Interdepartmental Program, David Geffen Medical School at University of California, Los Angeles, California. Electronic address: jld@jsei.ucla.edu.

Abstract

Purpose: To ascertain deformation of the optic nerve head (ONH) and peripapillary tissues caused by horizontal duction.

Design: Prospective, experimental study.

Methods: Optical coherence tomography of the ONH region was performed in 23 eyes of 12 normal volunteers in central gaze and increasing (10, 20, and 30 degrees) adduction and abduction. Main outcome measures were changes from central gaze in the configuration of the ONH and peripapillary tissues in eccentric gazes.

Results: Adduction but not abduction was associated with significant, progressive relative posterior displacement of the temporal peripapillary retinal pigment epithelium (tRPE) from its position in central gaze reaching 49 ± 10 μm in 30-degree adduction (standard error of mean, P < .0001). Absolute (anterior or posterior) optic cup displacement (OCD) averaged 41 ± 7 μm in 30-degree adduction. Linear regression showed significant effect of adduction on absolute OCD (slope 1.09 ± 0.36 μm/degree, P = .0037). In 20-degree and 30-degree adduction, all eyes exhibited significant progressive temporal ONH tilting reaching 3.1 ± 0.4 degrees in 30-degree adduction (P < .0001). Abduction was not associated with significant peripapillary RPE displacement, OCD, or ONH tilt. Both nasal and temporal peripapillary choroid averaged 9-19 μm thinner in adduction and abduction than in central gaze (P < .02).

Conclusions: Adduction temporally tilts and displaces the prelaminar ONH and peripapillary tissues. Both adduction and abduction compress the peripapillary choroid. These effects support magnetic resonance imaging and biomechanical evidence that adduction imposes strain on the ONH and peripapillary tissues. Repetitive strain from eye movements over decades might in susceptible individuals lead to optic neuropathies such as normal tension glaucoma.

MeSH terms

Choroid / diagnostic imaging*
Eye Movements*
Female
Follow-Up Studies
Healthy Volunteers
Humans
Male
Nerve Fibers / pathology
Optic Disk / diagnostic imaging*
Optic Nerve Diseases / diagnosis*
Prospective Studies
Retinal Ganglion Cells / pathology
Retinal Pigment Epithelium / diagnostic imaging*
Tomography, Optical Coherence / methods*
Young Adult

Abstract

MeSH terms

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