“Are those my vessels I see, doctor?”
Many observant patients have asked me this as I’m examining their eyes.
“Yes, you are seeing your own retinal vessels,” I say.
“But how?” they ask.
Well, we see because light passes into our eyes and meets the retina lining the inside of the back of our eyes. The retina is a very thin membrane packed with special photo cells that take that light and change it into usable information that goes on back to our brain. If you think of all the zillions of visual pieces of data our two retinae process in just a single day, you can begin to understand the complex workings of our eyes. So complex, in fact, that in order to be more efficient, our minds cancel out unimportant information to better focus on our daily visual needs.
You may, for example, be so focused on watching the dozens of “alien critters” in Men In Black that you don’t even notice your dog Frisbee entering the room and sitting down beside you. Frisbee is not as important in that moment than watching the aliens. So your mind sorts through all of that and refines.
Here’s another way of looking at it:
One day I went with my friend in her car for lunch. I immediately noticed a big starburst crack in her windshield and I asked, “How can you drive looking through that cluster of cracks all the time?”
She said, “Oh that. A year ago I was parked at Pebble Beach and a golf ball hit the window. I’ve never gotten around to fixing it and until you just reminded me, I’ve not noticed it for months!”
I tell this story because this is exactly what your mind does with all of the blood vessels in your eyes. Your optic nerve is actually a portal that holds the blood vessels going in and out of your eye and they look something like “cracked mud,” some say.
And, your retina actually sits behind all of that! Yes, your retina has to look through all that stuff 24-7. But you are not aware of it because it’s unimportant data. When I, your eye doctor, shine a bright light in your eye that casts a shadow at an unusual and new angle, your brain suddenly sees it! Just like my friend who now, thanks to me, notices the cracked windshield again.
Keep those great observations and questions coming.