Visual acuity question

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AnthonyL Senior Member • Posts: 2,901
Visual acuity question

I'm only looking for a basic understanding of visual acuity and so went to

https://en.wikipedia.org/wiki/Visual_acuity

The maximum angular resolution of the human eye is 28 arc seconds or 0.47 arc minutes[15], this gives an angular resolution of 0.008 degrees, and at a distance of 1 km corresponds to 13.6 cm. This is equal to 0.94 arc minutes per line pair (one white and one black line), or 0.016 degrees.

I'm happy with the above.

For a pixel pair (one white and one black pixel) this gives a pixel density of 128 pixels per degree (PPD).

This seems to have jumped a step and thus I'm not able to follow the logic to get to:

6/6 vision is defined as the ability to resolve two points of light separated by a visual angle of one minute of arc, corresponding to 60 PPD, or about 290–350 pixels per inch for a display on a device held 25 to 30 cm from the eye.[16]

I'm sure I'm missing the obvious but I feel I'm going around in circles and would appreciate a nudge in the right direction to understand the article.

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