Re:My Adventures with “4K” 2160p and Linux
by jacobolus on Sunday December 14, 2014 @04:29PM
(#8749625)
> The optimal viewing distance for reading is called the Harmon Distance.
I’m not an expert here (I had to look up the Harmon Distance), but from what I understand from other reading about eye strain, this should be rephrased as:
“Reading gets less comfortable if the material is any closer than the Harmon Distance, with some variation depending on age and individual differences between people.”
In particular, there are two factors that make focusing at close distance uncomfortable: (1) you need to flex the ciliary muscles to focus the lens (this is called “accommodation”), and (2) you need to flex the medial rectus muscles to rotate the eyes inward to point at the same spot (this is called “convergence”).
Both sets of muscles start getting strained if you look at a very close object for a long time with no breaks.
Looking at further away objects, even all the way out to the horizon, isn’t really a problem though.
I’m not an expert here (I had to look up the Harmon Distance), but from what I understand from other reading about eye strain, this should be rephrased as:
“Reading gets less comfortable if the material is any closer than the Harmon Distance, with some variation depending on age and individual differences between people.”
In particular, there are two factors that make focusing at close distance uncomfortable: (1) you need to flex the ciliary muscles to focus the lens (this is called “accommodation”), and (2) you need to flex the medial rectus muscles to rotate the eyes inward to point at the same spot (this is called “convergence”).
Both sets of muscles start getting strained if you look at a very close object for a long time with no breaks.
Looking at further away objects, even all the way out to the horizon, isn’t really a problem though.