GMC14 project protocol

Eye morphology and vision assessment in 8 inbred founder strains of the Collaborative Cross   (2020)

German Mouse Clinic and Department of Infection Genetics, HZI
With: Hrabě de Angelis M, Fuchs H, Gailus-Durner V, Amarie O-V, Graw J, Lengger C, Kollmus H, Schughart K

See also: GMC14 animal documentation


German Mouse Clinic: Phenotyping Pipeline

Eye morphology and vision assessment: 14-17 wks of age

 

  • Project protocol - Contents

    Workflow and sampling

    Step
    Procedure
    Data collected
    1 Body size assessment Body weight, body length
    2 Scheimpflug imaging Anterior eye parameters (lens)
    3 Optical coherence tomography Posterior eye parameters (fundus, retina)
    4 Laser interference biometry

    Eye size

    5 Virtual vision test Visual assessment

    Many other eye parameters are available in the Supplemental data file (see GMC14 Downloads)

    Equipment and supplies

    • Scheimpflug imaging: Oculus GmbH (Pentacam)
    • Optical coherence tomography: Heidelberg Engineering GmbH (OCT Spectralis)
    • Laser interference biometry: Carl Zeiss Meditec (AC Master)
    • Virtual optomotor system (virtual drum): Cerebral Mechanics (Optomotry), Lethbridge CANADA

    Reagents and solutions

    • Ketamine
    • Xylazine
    • Atropine

    Procedure: Eye morphology and vision assessment

      1. Scheimpflug imaging:
        1. The Pentacam is turned on and patient data managment started.
        2. One drop of 0.5% Atropine is applied to each eye to dilate the pupil.
        3. The "1 picture" modus is activated in the "Image Options" area.
        4. The Pentacam is moved to the right position.
        5. The mouse is held on the platform such that the vertical LED 475 nm light slit is oriented in the center of the eye ball.
        6. Optimal focus is attained by using the fine adjustment software tool in the adjustment window.
        7. The "Start Scan" button is pressed for manual imaging; Scheimpflug images are saved automatically.
        8. The Pentacam is moved to the left eye and the procedure repeated.
      2. Optical coherence tomography:
        1. The OCT is turned on and the database started.
        2. Mice are anesthetized with ketamine-xylazine.
        3. Eyes are prepared with Atropine drops and the contact lens (focal length 1 mm) is placed on the right eye.
        4. Measurement modus is activated.
        5. The mouse is placed collaterally to the camera on the right side of a platform that is fixed in front of the OCT lens.
        6. The fundus is focused by slightly moving up/down or forward/backward.
        7. Fundus images are saved.
        8. The "Ref.Arm" ruler is set such that the section of the retina is placed in the cneter of the blue rectangle.
        9. The mode "vertical, horizontal line" is set.
        10. The blue horizontal line in the fundus image field is moved to the optic nerve level.
        11. Images of retinal sections are saved.
        12. The OCT camera is moved to the left eye and the procedure repeated.
      3. Laser interference biometry:
        1. Mice are anesthetized with ketamine-xylazine.
        2. Mice are placed on a platform and oriented in an appropriate position using light signal from six infrared LEDs arranged in a circle that must be placed in the center of the pupil.
        3. Central measurements of axial eye length are taken.
      4. Virtual vision test:
        1. A rotating cylinder covered with a vertical sine wave grating is calculated and drawn in virtual three-dimensional space on four computer monitors facing to form a square.
        2. Rotation speed and contrast are set to 12.0 deg/s and 100%, respectively.
        3. Vision threshold is quantified by a randomized simple staircase test (visually unimpaired mice track the grating with reflexive head and neck movements (head-tracking)).

    Data collected by investigator

    • Body weight
    • Body length
    • Axial eye length (left, right)
    • Density of lens (left, right)
    • Number of main vessels in the fundus (left, right)
    • Retinal thickness (left, right)
    • Threshold of spatial frequency
  • Many other eye parameters are available in the Supplemental data file (see GMC14 Downloads)