What happens when your eyes have poorly trained editors
April 10, 2007 2:03 PM   Subscribe

Jump-Cut Vision Filter: Sometimes, for no reason, I'll see a jump cut. Literally. My frame of vision will jump to the left by certain degree. I will not be moving my eyes or turning my head. But, out of nowhere, the entire field of view will move, slightly, to the left or right in a jarring fashion. Like a jump cut. So...is this a tumor or something?
posted by rileyray3000 to Health & Fitness (15 answers total) 1 user marked this as a favorite
When you say you aren't moving your eyes, do you mean you aren't moving them willingly or your eyes are physically not moving?
posted by pravit at 2:09 PM on April 10, 2007

It's not a tuuuumor!

I wouldn't be necessarily worried about cancer, but go see your eye doctor if you're worried. Have you been tired lately? Visual artifacts can happen when you don't sleep for a while.
posted by chrisamiller at 2:16 PM on April 10, 2007

I had this and similar vision anomalies while on morphine, demerol, and steroids after major surgery...

see your doctor.
posted by clanger at 2:26 PM on April 10, 2007

I get this all the time and have never found it worrisome. Always assumed it was just a caffiene twitch or something.
posted by sonofslim at 2:31 PM on April 10, 2007

This happens to me during migraines.

or when I'm playing a lead in an aronofsky film.
posted by Baby_Balrog at 2:59 PM on April 10, 2007

How's your balance? Do you ever lose your footing while walking in the dark, or on uneven surfaces?

If so, then I think a) opthamologist, b) neurologist, c) physical therapist specializing in vestibular issues (they usually work with audiologists).

See a) first, if they can't figure it out, b), et cetera.

posted by jennyjenny at 3:16 PM on April 10, 2007

Opthamologists will cheerfully give you a clean bill of health just for having nothing wrong with your eyes. They don't really look at what else might be terribly wrong. So if your opthamologist says they can't find anything wrong, see a doctor who _can_ figure out what is happening.
posted by yohko at 3:29 PM on April 10, 2007

Are you on any medication? I get that when I haven't taken my Lexapro on-time; it's my first sign of withdrawl. If you're on meds I would make an appointment with the doctor that prescribed them first.
posted by lilac girl at 3:44 PM on April 10, 2007

Eyes normally saccade, that is, even you think you're staring at one point, the eyes move. This is good, because it allows you to detect motion, among other things.

But the saccades are normally "edited out" of conscious perception.

In fact, since your retinas can't sense motion by themselves, motion is "edited in" in the visual cortex. Brain damage, especially to the MT/V5 area can cause motion blindness.

See a neurologist.
posted by orthogonality at 4:17 PM on April 10, 2007

I get that occasionally.
I used to get it a lot way back in the day when I'd spend an afternoon playing Doom or Marathon or something. Pixel saturation.
posted by Thorzdad at 5:03 PM on April 10, 2007

Back when I was a whippersnapper and experimenting with the old maryjane (before it became clear that I just didn't like it much), I'd get that effect (amongst others) when I was really, really high. That may not help your situation, though, I admit.
posted by stavrosthewonderchicken at 5:23 PM on April 10, 2007

I have it too -- and "jump cut" is exactly how I describe it.

In my case, though, I have a pretty good idea what the cause is. A year or so ago, I had minor surgery to correct my strabismus. I've got mild lateral nystagmus too.

Put the conditions together, plus a change in the vision system, and my brain just hasn't been able to process things quite right since. For example, I'll just be reading, and--boom--the words will shift slightly. Or looking at something a ways away, blink, and it moves. Speaking subjectively, I tend to get it more when looking at an object in front of a uniform background, which makes me think it's something neurological. So while I'm not quite sure what the fix is, but at least I know where my problem came from.

See an ophthalmologist (not just an optometrist.) If they can't find a cause, a neurologist is probably a good second port of call.

(And me, I should heed my own advice.) Good luck.
posted by theoddball at 5:44 PM on April 10, 2007

I'll preface this by saying I know just enough about the eyes and brain to fill a few paragraphs worth of rambling, so please take this with a grain of salt.

My inclination is that whatever it is is not harmful. The brain, and nervous system in general, are prone to developing all sorts of strange tics and feedback loops, and if this thing you are experiencing isn't that common, and isn't affecting your life beyond making you worry about a potential neurological problem, I wouldn't worry about it. (unless of course, you notice it getting worse-- then seek an expert quickly)

As examples, how many people have stuttered, had a case of hiccups that wouldn't go away, experienced a myoclonic jerk as they fell asleep, have a benign tremor in their hand, experienced sleep-paralysis, have a facial tic, had pee-shivers, exhibit the knee-jerk reflex, etc. Not all of these things are experienced by everyone, but they are all somewhat common, and they are all side-effects of important aspects of nervous system function.

If you want a guess as to where in the nervous system they originate, I don't think I would lean toward V5/MT problems. orthogonality's link is a textbook case of V5/MT damage-- the inability to perceive the sense of motion at all.

My guess would be that your tic would be located somewhere in the complicated circuits that control and interact with eye-movements. People execute large saccades (over >10 deg) every 200-300ms. But, these are things we barely notice. It is quite incredible that we can completely lose our entire visual frame of reference (in terms of the pattern of light falling on our retina) some five times a second while at the same time experiencing seamless continuity of our sense of space.

The mechanism that helps us through this is called corollary discharge. At approximately the same time your brain sends a signal to the eye muscles that move your point of fixation (ie, execute a saccade) there is an accompanying neural signal sent to the areas in your brain that represent space that encodes the eye movement. This corollary discharge adjusts your mapping of retinal space to world space in a precisely opposing manner to the discontinuity induced by the saccade. In other words, it is a signal that simultaneously shifts your mind to compensate for the shift of your eyes.

I would guess that the problem you describe is some sort of glitch in this system-- some sort of "corollary discharge" without the saccade.
posted by Maxwell_Smart at 5:46 PM on April 10, 2007

Could you be switching dominant eyes? I, uh, had some interesting vision problems in the past, and, from the little tricks you can do to test, don't seem to have a dominant eye. I get a jump effect when I switch from one to the other.
posted by adipocere at 5:49 PM on April 10, 2007

The above replies contain far more educated speculation than I have to offer, but my concern would be that you see your provider to eliminate, among others, an impending retinal detachment, or elevated intra-ocular pressure, which could be a warning sign of hypertension.
posted by dunderhead at 9:13 PM on April 10, 2007

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