September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Non-linear changes in the pSTR and ERG responses of the rat retina to visual stimulation for different levels of elevated IOP
Author Affiliations & Notes
  • Bingyao Tan
    Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
  • Benjamin MacLellan
    Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
  • Erik Mason
    Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
  • Vivian Choh
    School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
  • Karen M Joos
    Vanderbilt Eye Institute, Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, Tennessee, United States
  • Kostadinka K Bizheva
    Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
    School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
  • Footnotes
    Commercial Relationships   Bingyao Tan, None; Benjamin MacLellan, None; Erik Mason, None; Vivian Choh, ARVO AP AMPC member (S); Karen Joos, ARVO CME Committee Chair (S); Kostadinka Bizheva, None
  • Footnotes
    Support  Natural Sciences and Engineering Research Council (NSERC) Discovery Grants, Joseph Ellis Family Glaucoma Research Fund; William Black Glaucoma Research Fund; NIH 5P30EY008126­27 to Vanderbilt Vision Research Center; Unrestricted Departmental Grant from Research to Prevent Blindness, Inc., N.Y. to the Vanderbilt Eye Institute, Canadian Foundation for Innovation Leaders Opportunity Fund
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 6421. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Bingyao Tan, Benjamin MacLellan, Erik Mason, Vivian Choh, Karen M Joos, Kostadinka K Bizheva; Non-linear changes in the pSTR and ERG responses of the rat retina to visual stimulation for different levels of elevated IOP. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6421.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose : To evaluate the retinal response to visual stimulation at different levels of elevated IOP.

Methods : One group of eleven-week old male Brown Norway (n=6) rats were dark-adapted for at least 12 hours before isoflurane anesthesia. The IOP of the right eye was raised from 10 mmHg to 70 mmHg in steps of 20 mmHg using a vascular loop anterior to the equator of the eye. The left eye was left untouched and served as control. Corneas were anesthetized and pupils were dilated prior to collection of scotopic threshold responses (STRs) or full-field Electroretinography (ERG) from both eyes simultaneously. Measurements were conducted at baseline, all steps of elevated IOP and at recovery, thirty minutes after loop removal.

Results : The pSTRs magnitude increased significantly from baseline IOP = 10 mmHg to 30mmHg (p<0.0001), and decreased by ~20 % for 50-mmHg (p=0.0002). As the IOP increased further to 60mmHg, pSTR amplitude decreased significantly (p=0.0496) relative to 50mmHg and was on average 9.4µV lower than the baseline, though not significantly (p =0.5903). The STR amplitude at 70-mmHg was significantly lower than the baseline (p=0.0063) and recovered to baseline within 30 min after the loop removal. In general, significantly larger implicit pSTR times (p=0.0010) were measured at higher IOP, however, there is no significant difference between the baseline and recovery measurement (p=1.0000).
The ERG a-wave amplitude increased significantly (p<0.0001) from baseline to 30 mmHg and remained relatively constant up to 60mmHg, then sharply decreased to baseline for IOP= 70 mmHg. The ERG b-wave amplitude increased significantly from baseline and peaked 30 mmHg, then progressively declined to baseline until ~55 mmHg. For IOP of 60 mmHg and 70-mmHg, the b-wave magnitude was significantly lower than baseline (p = 0.0038 and p=0.0013, respectively).

Conclusions : Results from this study suggest that acute increase of the IOP can alter the normal retinal physiology, and provide better understanding of the mechanism of early degeneration in retinal ganglion cells induced by increased IOP.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×