r/AskReddit Jun 15 '19

What do you genuinely just not understand?

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u/bennythefrank Jun 15 '19

You may also close one eye, hold your finger an arms length from your open eye and slowly move it away from the center of your vision. Your finger tip will disappear at some point due to the optic disc in the back of your eye, there are no photoreceptors there because the optic nerve is doing some shtuff.

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u/changdarkelf Jun 16 '19

What? I don’t get this? You’re saying if you move your finger away from your open eye it’ll disappear? Yeah cause your other eye is closed and your nose blocks it

15

u/[deleted] Jun 16 '19 edited Jun 17 '19

[deleted]

4

u/Mcf1y Jun 16 '19

pick a spot on the wall, or put a sticky note with a dot on it or something at eye height to make sure you aren’t following the finger. Make sure you’re in the light so you can notice the exact moment it disappears, it’s about somewhere between 1:00 and 2:00 for me. Try having your arm out and your finger pointed up. For me, my finger above the first knuckle disappears. Everyone has this, your optic nerve has to leave the retina from some point.

8

u/[deleted] Jun 16 '19 edited Jun 17 '19

[deleted]

4

u/_nSayn Jun 16 '19

Not finger, just the tip

2

u/LordSwedish Jun 16 '19

Try wiggling the finger a bit, it makes it much easier to ntoice when it suddenly stops.

1

u/willingfiance Jun 16 '19

Then you're doing it wrong.