The answer to the puzzler of “why did sailor’s often have patches over one eye?” was because of taking celestial sightings of the sun for navigational purposes.
As I remember the operation of the Sextant, the lower limb of the sun was brought down to the horizon for the angular determination. The sun’s disc was reflected twice to get to the eye piece and there are several filters to reduce the intensity of the light input. So the sailor’s eye is not looking directly at good old Sol and often through a filter. So the possibility of retinal burnout, is highly suspect.
I suspect the reason for loss of an eye is the hazards of handling sheets, tacks, lines, sails, reef points, etc. in high wind conditions. Consider the euphanism of “three sheets to the wind”. Another possibility is flash from firing flint lock weapons or lighting off cannons i.e spit back from the firing hole.
Anyway, does anyone else have a more authorative sailing risk which would cause loss of an eye for a fully rigged ship, Bark, or Barquentine…
I thought that I had heard something recently about that subject.
That the sailor wore the patch over one eye so that that eye was acclimated to the dark when he went below.
But I can’t remember where I heard that.
Yosemite
Of course, the sailor must remember to put the sun filters in place. But why would a burned retina necessitate an eye patch? I also tend toward the “flying object” answer.
Mythbusters did an episode about this,using the theory of keeping one eye acclimated to the dark.
I’ve heard what @Yosemite heard - though it was explained to me that it was for boarding enemy ships - you wanted good night vision when going below decks in an unfamiliar ship looking for people who might be hiding until you’re not ready for them to attack you.
It’s all unsubstantiated, though. I do know that a lot of what we think we know about ancient sailors is myth. It’s entirely possible the eye patch was not all that commonly worn at all - much of what we think we know about how historical people looked is false. For instance, ancient Egyptians did not, shockingly enough, look like Elizabeth Taylor. 
ancient Egyptians did not, shockingly enough, look like Elizabeth Taylor.
If they did, we might be overrun with Egyptians!
@shadowfox did see the same thing as I. Now I remember that it was for boarding other ships and being able to see anyone hidden below in the dark recesses.
That must have been something on Nat Geo or the history channel…that’s about all I watch other than the news. I have a large collection of old classic’s and documentaries on DVD and when I get bored of the few programs of any quality on TV…I break out a old movie.
Yosemite
Cleopatra was of Greek or Roman family origin wasn’t she? I seem to recall she wasn’t Egyptian.