July 2019
Volume 60, Issue 9
Free
ARVO Annual Meeting Abstract  |   July 2019
Investigation of parameters to quantify local variations in the circumpapillary retinal nerve fiber layer on OCT circle scans of eyes with early glaucoma.
Author Affiliations & Notes
  • William Eugene McKee
    Psychology, Columbia University, New York, New York, United States
  • Emmanouil Tsamis
    Psychology, Columbia University, New York, New York, United States
  • Katherine Tsang
    Psychology, Columbia University, New York, New York, United States
  • C Gustavo De Moraes
    Ophthalmology, Columbia University, New York, New York, United States
  • Donald C Hood
    Ophthalmology, Columbia University, New York, New York, United States
    Psychology, Columbia University, New York, New York, United States
  • Footnotes
    Commercial Relationships   William McKee, None; Emmanouil Tsamis, None; Katherine Tsang, None; C Gustavo De Moraes, Carl Zeiss (F), Galimedix (C), Heidelberg Eng (F), Lin Biosciences (C), Novartis (C), Topcon (F); Donald Hood, Heidelberg Eng (F), Heidelberg Eng (C), Heidelberg Eng (R), Novartis (F), Novartis (C), Novartis (R), Topcon (F), Topcon (C), Topcon (R)
  • Footnotes
    Support  NIH Grant EY02115
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 150. doi:
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      William Eugene McKee, Emmanouil Tsamis, Katherine Tsang, C Gustavo De Moraes, Donald C Hood; Investigation of parameters to quantify local variations in the circumpapillary retinal nerve fiber layer on OCT circle scans of eyes with early glaucoma.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):150.

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

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Abstract

Purpose : Local glaucomatous damage seen on circumpapillary retinal nerve fiber layer (cpRNFL) images and thickness plots of optical coherent tomography (OCT) circle scans can vary in location, width, depth, and heterogeneity.[1] To quantify and characterize these local variations, we developed an automatic, quantitative tool to calculate various parameters.

Methods : Heidelberg spectral-domain OCT circle scans of the disc, with a diameter of 3.5mm, were obtained from 64 eyes (31 early glaucomatous and 33 healthy controls). Measurements of cpRNFL thickness were extracted and imported in a custom Python program that investigated 4 regions of interest (where 0° is at 9 o’clock for the right eye): inferior nasal (from -90° to -135°), inferior vulnerability zone (IVZ; -45° to -90°), superior vulnerability zone (SVZ; 45° to 90°) and superior nasal (90° to 135°).[1] The program calculated 3 parameters: a) Minimum Thickness (minT) as a measure of depth of damage, b) Average Thickness (avT) as a measure of level of damage and c) Standard Deviation of thickness (sdT) as a measure of heterogeneity. Parameters were compared between the two groups (i.e. control vs glaucoma), and between the 4 regions. For each region, a 95% confidence interval (CI) was calculated from the distribution of controls.

Results : The table contains the number of glaucomatous eyes falling below the 95% CI for healthy controls, by region. The IVZ region had the most eyes significantly smaller on both the minT, and avT, 25 and 26 eyes respectively (Table). The number of eyes with smaller values in the SVZ region was notably close to the number of eyes found in the superior nasal region; in contrast to the inferior nasal region, which showed the fewest (Fig.). The sdT parameter did not have face validity as it did not capture the range of local variation in damaged region. In addition, a measure of variation in contrast may also be needed.

Conclusions : As expected, the IVZ is the region most affected by glaucomatous damage at the early stages of the disease. Parameters such as minT and avT could potentially be used to characterize local variations in the different regions of the cpRNFL. 1. Hood DC. PRER, 2017

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

 

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