When you close both of your eyes you see black, but when you close one you don’t see half black.
When you close both of your eyes, you perceive darkness because both eyes are essentially blocking out light. Your brain interprets this lack of visual input as darkness.
However, when you close only one eye, the other eye remains open and continues to receive visual input. The open eye continues to send signals to your brain, which interprets the visual information it receives. Therefore, you don’t perceive half of your visual field as black because your brain is still processing the visual input from the open eye, and you perceive whatever you’re looking at with that eye. The closed eye simply doesn’t contribute to the visual input being processed by your brain at that moment.
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On a more serious note, I have a left eye that used to be excellent when I was young and a right eye which started out being blind. I was super lucky. My Mom (go with my American spelling. That’s another story) caught Rubella (German Measles) in her last trimester with me on board.
I was SUPER lucky.
It’s a bastard of a virus and can cause serious birth defects right up to stillbirth. My only other outward damage is fairly short fingers. The only piano I can cope with is like Schroeder’s in Peanuts.
But my right eye has fascinated me all my life. The pupil is not in the centre (which probably explains my left leanings).
Our impecunious family was also lucky in that a top opthalmic surgeon (Harley Street style) took me on pro-bono as part of his research – for which he received a knighthood. Not my eye. We were just onlookers (apologies, sometimes I just can’t help myself).
Anyway, as a toddler, first I got the perception of light and dark in the bung right eye and later colour, notwithstanding that I have mild red-green blindness (this my mother’s mother’s fault). Thanks, Nan ! My uncle had it too.
At best the dud eye has pulled in 20-25% of the information that a normal eye would do – and then focused the light not on the most sensitive part of the retina where the optic nerve enters the eye.
But to your point, a recent eye examination revealed that I would need spectacles with LESS powerful lenses ! My optometrist said “Don’t get too excited. Your eye is still shit (apparently a specific opthalmic term)… But your brain has worked out a better way to process the rubbish signal !
And then he added the kicker. Apparently I am developing cataracts – common as mud at my age and he said “Don’t worry, mate. The new lenses inserted into your eyes will make you see far better than you’ve ever done before… and you won’t need spectacles because your prescription will be built in !
Provided I don’t crap myself over the idea of some dude (not my long departed Sir Norman McAllister-Gregg) will be playing around with sharp pointy objects IN MY OPEN but immobilised EYES, the prospect of amazingly improved vision is quite exciting :-)
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Wow, what a story. I can’t stand the thought on someone bringing something sharp in to close vicinity, let alone close contact, with my eyes.
Just researched Norman Gregg. “He was Australian ophthalmologist best known for his pioneering work in identifying the link between rubella (German measles) during pregnancy and birth defects in the child. In the 1940s, he observed a significant increase in cases of congenital cataracts and other eye abnormalities in children whose mothers had contracted rubella during pregnancy. His research led to the recognition of congenital rubella syndrome.
Norman Gregg’s work was instrumental in highlighting the importance of vaccinating against rubella, especially for pregnant women, to prevent birth defects. He played a crucial role in raising awareness about the dangers of rubella during pregnancy and advocating for widespread vaccination programs.”
What an important man in your (and countless others) life. I have an ectopic fovia because I had a squint that was never corrected as a child an if it were to be corrected now I, too, would not be able to focus. What wonferful machines we are!
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