Added: 2 years ago
From: justinsparhawk
Views: 630
Sort by time | Sort by thread (beta)

Link to this comment:

Share to:

All Comments (4)

Sign In or Sign Up now to post a comment!
  • Hello! I am an optometry student having difficult with this question. is it possible you could help me understand this ... what is the optimal size of a pinhole used to estimate acuity? why? answer: 1.0mm; smaller will not sufficiently increase depth of focus, leaving refractive error, while larger will result in significant diffraction. Thank you i really appreciate it.

  • I would add the technical explanation is called "depth of field", or "depth of focus". The amount you can "clear your Snellen" can be on the order of 1 diopter -- by my testing.

  • thanks for explaining , i always had this question in my mind - u answered it :))

  • I would have drawn lines coming in from different angles like a sunray diagram. The middle lines go straight to the retina and don't require refraction. By squinting, you're cutting out the lines that come at angles and need refraction.

Loading...
Alert icon
0 / 00Unsaved Playlist Return to active list
    1. Your queue is empty. Add videos to your queue using this button:
      or sign in to load a different list.
    Loading...Loading...Saving...
    • Clear all videos from this list
    • Learn more