How long in darkness to go blind

It's easy to take light for granted. We wake up every morning and it greets us through the windows. We come home from work and summon it with the flick of a switch. The dull glow of one last glance at your phone bathes us, even as we try to fall asleep. Lights signal progress, opportunity. We are drawn to bright lights and big cities, even as they drown out the light from much, much larger celestial bodies burning and exploding far, far away.

So many of us concern ourselves with an excess of light in our lives , but what about the opposite? What might happen if you were to plunge yourself into total, unending darkness and never leave? We spoke with Dr.

Karl Citek , an optometrist and professor of Optometry at Pacific University, to shed some light on this dark hypothetical. Initially, everything is fine. Your mind might be racing, struggling to pick up on the slightest bit of sensory information. There might be bumps you may or may not have heard, or brushes against your skin you may or may not have felt. But that's all in your mind.

It takes a little while for your eyes to physically adjust. Your eyes rely on two overlapping systems for visual perception. As you might already know, within your retina sit a number of rods and cones.

Our current understanding of our eye is that these rods and cones work in tandem to create a composite image that we all know and love as our vision. The cones are there to help us see color and detail, this is known as our photopic vision.

The rods are responsible for our sensitivity to light, which we call our scotopic vision. An easy way to think about this is that our photopic vision works well in in the daytime, and our scotopic vision becomes useful only when it gets dark out. A day vision and a night vision, if you will. As such, when the lights go out, your photopic vision is the first to fully adjust. Though "fully adjust" is a bit of a misnomer. After about 7 to 12 minutes, your photopic vision is maxed out in terms of the amount of color and detail you could possibly see in complete and utter darkness.

Your scotopic vision takes a little longer, fully maxing out its sensitivity in around 45 minutes to an hour. Even now, although your eyes are fully cranked, without any light, you can't see anything. This might seem disorienting at first, since you're always used to seeing something, but the real terror will only manifest itself hours, maybe even days later.

Your body relies on light to determine when it should release melatonin, and thus when you should go to sleep. Without light, your brain doesn't know when, if at all, to release that sweet, sweet melatonin. So, somewhat counterintuitively, sitting in the dark will eventually leave you sleep deprived.

You'll just be sitting there, staring into absolute darkness, wishing you could fall asleep but cannot. There's no telling what sort of mental toll this will take on you, but physiologically speaking, your eyes are fine.

They might be cranked to maximum sensitivity, but they aren't straining or degrading. They are just sitting in your head, trying to take in the light that doesn't exist. In fact, if you were to be suddenly thrust back into the light, things would go back to normal in a matter of moments. Granted, your eyes are still set to Maximum Sensitivity, so any abrupt changes in light might feel harsh. After a few seconds, it would be like nothing ever happend at all.

Darkness thrusts you into a incomprehensible sea of fear and isolation. It's easy to see things that aren't there, believe things that seemed impossible moments before. You might believe your eyes are straining so hard that you'll never see again. But take comfort in the fact that no matter how dark it gets, no matter how interminable it may seem, eventually the light will return.

You don't really need science to know this is Bravo Sierra Countless prisoners have been kept in solitary confinement in total darkness for way more than 3 days Giant Duuuuuuh! It's just another "Three Musketeers" thread from the sockpuppet.

May 28th, , PM. I've heard that if you spontaneously combust ideally at negative temperatures for 3 days you go blind. Is that correct? Don't start two separate threads about the same subject. Photoreceptors in eyes aren't made of muscle tissue. Cogito Ergo Sum. Originally Posted by Daecon. Grief is the price we pay for love. CM Parkes Our postillion has been struck by lightning. Unknown War is always the choice of the chosen who will not have to fight.

Bono The years tell much what the days never knew. RW Emerson Reality is not always probable, or likely. JL Borges. May 29th, , AM. Originally Posted by PhDemon. I didn't, I insulted the OP by reference to that work and it's author. For this reason, many people think that after only a few minutes, their eyes have reached their peak sensitivity.

But several hours into darkness exposure, the human eyes continue to adapt and make small gains in sensitivity. There are several factors that contribute to our eyes adapting to darkness.

As described in the textbook Optometry: Science Techniques and Clinical Management , edited by Mark Rosenfield and Nicola Logan, the three main players in dark adaptation are the pupil, the cone cells, and the rod cells.

The pupil is the dark hole near the front of your eye that lets the light into your eye so that the light can form an image on the back the retina. The iris that surrounds the pupil contains muscles that control the size of the pupil. When confronted with low light conditions, the iris expands the pupil as wide as possible. This dilation lets as much light as possible into the eye so that sensitivity is enhanced.

The pupil's contribution to dark adaptation takes only a few seconds to a minute to be completed. The cones cells along the retina are responsible for color vision.

Similar to a grid of pixels in a digital camera, a vast spatial array of cone cells along the retina detect the different bits of colored light that make up the image we are seeing. Human eyes have red-, green-, and blue-detecting cone cells.

All other colors that exist are experienced by humans as a mixture of red, green and blue. The cone cells themselves can adapt to partial darkness.