BSN PSP/CBD Conference – Heather Moss


Vision Symptoms in PSP & CBD: What Causes Them and What Can be Done?

Heather Moss, MD, Stanford

  • Eye movements are critical to vision
    • Coordinated by the brain – how vision gets from the eye back into the brain, and gets interpreted in the brain
  • Although there can be problems with perception, eye movements are the biggest problem
  • Vertical gaze palsy in PSP
    • The eyes have a problem looking down more so than up
    • Not a problem with the eye mussels or nerves, it’s a control problem (determined by reflex movements)
  • Inability to move the eyes can interfere with navigation
    • With PSP, your eyes do not look down, but straight ahead
    • No ways to make eyes move better, but if you are aware of it, there are tips
    • Using head position to compensate for eye movements
  • Inability to move the eyes can interfere with using glasses
    • Bifocal glasses don’t work well if you have a vertical gaze problem
    • Distance in top, near on bottom
    • Need to move your eyes to use them, but moving your head isn’t going to be helpful for this, because your glasses will move with you
    • Solution: have single distance glasses for near and distance (2 pairs)
      • Then you can position your eye gaze with head movement
  • Misalignment of eyes causes double vision
    • Inability to move the eyes together or apart can lead to double vision
    • Normally when you look straight ahead your eyes come together a bit to focus
    • If you cant bring eyes together, it creates double vision at near
  • Divergence insufficiency
    • When your eyes are not going apart at distance, then you see double as well
  • Strategies for treatment of double vision
    • Optically align the images by using prisms (prism insert in glasses lens)
    • Block one of the images

Trouble moving the eyes affects dynamic eye movements as well

    • Saccades – eye movements used to look around at things (looking at 2 things on opposite ends)
    • Smooth pursuit – tracking a movement moving across your visual field
  • Rapid eye movements in PSP and CBD have delayed initiation and fall short of target
    • CBS – longer delay time and then quick jump up
    • PSP – longer delay and slower movement to get up to target
    • Smooth pursuits
      • CBS – slow speed of following target, never reaches, behind
      • PSP – slow speed of following target, never reaches, behind
  • How does it apply?
    • Looking at an object
    • Reading
      • Need to move eyes through lines of text
  • Left to right reading task in person with Parkinson’s disease
    • With no disease (12 seconds)
    • With Parkinson’s disease (21 seconds) (another patient took 119 seconds)
  • Strategies – Trial and Error
    • Line guide (isolates lines when reading)
    • Font size, spacing (accessibility features)
    • Color, contrast
    • Audio
  • Visual perception is also critical to vision
    • Glaucoma
    • Cataract
    • Macular Degeneration
  • Take home points
    • Can’t look down?
      • Move head
      • Single vision glasses (not bifocals)
    • Double vision?
      • Patch/cover one eye
      • Prism glasses
    • Trouble reading?
      • Adjust display
      • Reading guide
    • Keep your eyes healthy
    • Have the right prescription