April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
The Magnitude of IOP Spikes Associated with Blink and Saccade
Author Affiliations & Notes
  • Anna Edmiston
    Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL
  • Daniel C Turner
    Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL
  • Lisa A Hethcox
    Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL
  • Christopher A Girkin
    Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL
  • J Crawford C Downs
    Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL
  • Footnotes
    Commercial Relationships Anna Edmiston, None; Daniel Turner, None; Lisa Hethcox, None; Christopher Girkin, None; J Crawford Downs, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 149. doi:https://doi.org/
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      Anna Edmiston, Daniel C Turner, Lisa A Hethcox, Christopher A Girkin, J Crawford C Downs; The Magnitude of IOP Spikes Associated with Blink and Saccade. Invest. Ophthalmol. Vis. Sci. 2014;55(13):149. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose
 

To determine the magnitude of IOP spikes associated with blink and saccade.

 
Methods
 

We have developed and validated an implantable telemetry system that wirelessly records 500 measurements of IOP per second for up to 2-1/2 years (IOVS 52(10):7365-75). Using an enhanced version of this system, continuous bilateral IOP, bilateral electro-oculogram (EOG), and aortic blood pressure were recorded in 3 young adult male rhesus macaques (NHP) aged 3-6 years old while watching a video of playing macaques. Eye movements and blinks were monitored using high-definition video of the animals’ faces recorded at 60 frames/s, which was synced to the IOP telemetry data to 33 ms precision. The IOP transducers were calibrated directly via anterior chamber manometry, and IOP data were corrected for signal drift. For each animal, the magnitude of IOP spikes associated with blinks and saccades seen in the video were calculated and reported relative to baseline IOP.

 
Results
 

As seen in the Figure, IOP is incredibly dynamic, with blinks, saccades and other external forces generating short-term IOP spikes of significant magnitude over baseline. Blinks generated IOP spikes ranging from 4.9 to 14.9 mmHg over baseline IOP, with an overall average of 8.9 mmHg above baseline. Saccades generated IOP spikes ranging from 2.0 to 13.4 mmHg over baseline IOP, with an overall average of 7.0 mmHg above baseline. Blinks and saccades generated very similar IOP spikes in contralateral eyes, and vertical and horizontal saccades generated IOP spikes of similar magnitude.

 
Conclusions
 

IOP is incredibly dynamic. Blinks and saccades generate large, short-term IOP spikes in NHPs. The eye is exposed to many IOP spikes throughout the day, which represents a significant but previously uncharacterized part of IOP energy. The dynamic nature of these spikes represents a different biomechanical insult than longer-term IOP fluctuations, and may be important in IOP-related diseases such as glaucoma.

 
 
Screenshot of 12 seconds of telemetry data from one NHP showing the dynamic nature of IOP and EOG, and identifying the IOP spikes associated with a blink and saccade.
 
Screenshot of 12 seconds of telemetry data from one NHP showing the dynamic nature of IOP and EOG, and identifying the IOP spikes associated with a blink and saccade.
 
Keywords: 568 intraocular pressure • 622 ocular motor control  
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