Measuring by seeing signs -- don't forget 3-D field of view

In gauging one’s vision by seeing “landmarks”, it is important – as indicated below – to be cognizant of

  • 3-D field of view
  • text of varying sizes within that 3-D field of view
  • being able to move one’s eyes to see text of different sizes and text at varying distances without losing clarity of vision as one’s eyes move
  • peripheral activity in the scene
  • colors
  • any possible inferences on texture
  • sounds in the scene

In seeing a Snellen chart, it is important to be able to see multiple lines clearly (rather than merely being able to read or see one particular line). Seeing multiple lines clearly would be an instance of incorporating 2-D field of view; the image below shows street signs whose text are essentially in a 2-D field of view:

The following scene has text that span a 3-D field of view:

PS: there is also the issue of type of fonts – for example, in the first scene above, I find it easier to resolve “HP world” compared to “Rasi Designer Boutique”.