July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
Mouse corneal topography, pachymetry, and keratometry utilizing OCT with keratometer validation
Author Affiliations & Notes
  • Alice Sicong Liu
    Ophthalmology, Duke University, Durham, North Carolina, United States
  • Dillon Brown
    Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
  • Rachel Elizabeth Conn
    Neuroscience, Emory University, Atlanta, Georgia, United States
  • Ryan P McNabb
    Ophthalmology, Duke University, Durham, North Carolina, United States
  • Machelle T Pardue
    Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, Georgia, United States
  • Anthony N Kuo
    Ophthalmology, Duke University, Durham, North Carolina, United States
    Biomedical Engineering, Duke University, Durham, North Carolina, United States
  • Footnotes
    Commercial Relationships   Alice Liu, None; Dillon Brown, None; Rachel Conn, None; Ryan McNabb, None; Machelle Pardue, None; Anthony Kuo, Leica (P)
  • Footnotes
    Support  NIH R01 EY016435 (MTP), Dept of Veterans Affairs Rehab R&D Research Career Scientist Award IK6 RX003134 (MTP); NIH R01 EY024312 (ANK)
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 185. doi:
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    • Get Citation

      Alice Sicong Liu, Dillon Brown, Rachel Elizabeth Conn, Ryan P McNabb, Machelle T Pardue, Anthony N Kuo; Mouse corneal topography, pachymetry, and keratometry utilizing OCT with keratometer validation. Invest. Ophthalmol. Vis. Sci. 2019;60(9):185.

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

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Abstract

Purpose : Corneal curvature (keratometry), topography and pachymetry maps are important clinical diagnostic tests; however, in animal models, many of these tests are currently unavailable. This limits our ability to characterize the animal cornea the same way we would clinically. Here, we describe the measurement of keratometry, topography, and pachymetry maps using optical coherence tomography (OCT) of mouse corneas with quantitative validation to a dedicated mouse keratometer.

Methods : Four eyes from two C57BI/6 mice and one D4R wild-type mouse aged 30-287 days were imaged using a spectral domain OCT (Leica EnVisu R2300) with a 12 mm anterior segment lens. To test repeatability, each eye was imaged three times per position (intrasession) with five re-positions (intersession). Images were segmented to detect the corneal epithelium and endothelium boundaries within the pupil (nominal optical zone), and resulting surfaces were corrected for optical distortions. Curvatures were calculated per ANSI standard for each corneal volume to create topography maps; pachymetry maps were created by direct subtraction of corrected endothelial and epithelial surfaces. Wilcoxon Signed-Rank test was used to compare the paired differences in corneal curvature between OCT and mouse keratometry (Schaeffel F. Front Biosci 2008).

Results : The epithelial radii of curvature calculated using our method (1438 +/- 13 µm, mean +/- SD) were within 1.5% of the mouse keratometer values (1455 +/- 18 µm). The mean paired difference was 17.3 µm (p = 0.8750). The standard deviation of repeated measures did not exceed 18 µm intrasession and 19 µm intersession. Using topography and pachymetry maps, corneal thinning was readily apparent in one of the eyes (Fig. 1) compared to a normal eye (Fig. 2).

Conclusions : We demonstrated a method to create corneal topography and pachymetry maps from mouse OCT analogous to those used clinically. Corneal curvature from OCT was not statistically different from keratometry. Because some clinical corneal diseases are defined by their topography or pachymetry map patterns, this work brings comparable corneal analysis tools to small animal models of corneal diseases.

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

 

Figure 1: Segmented OCT B-scan (A) of a mouse cornea with pathologic thinning (white arrow), corresponding color pachymetry map (B), and topography map (C, in radii of curvature).

Figure 1: Segmented OCT B-scan (A) of a mouse cornea with pathologic thinning (white arrow), corresponding color pachymetry map (B), and topography map (C, in radii of curvature).

 

Figure 2: A normal cornea for comparison to Fig. 1.

Figure 2: A normal cornea for comparison to Fig. 1.

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