Tuesday, June 24, 2014

Football without stereoscopic depth perception (video + optometric analysis)


As a strabismic child that suppressed one eye at the time, I played football (soccer) during every recess period at school. Clearly I had no stereo vision. Nonetheless I was a fairly good player and loved playing. I could be totally absorbed by it. At one point I also tried playing in a club. Because of my vision dysfunction I didn't have the energy to both keep up with my school work and go to the training sessions so I had to quit. Suppressing one eye is a wasteful business. I had good reading comprehension but read very slow and have never been able to fluently read aloud. Just doing my homework was enough of a physical training.

Therefore my football practice stayed confined to school recess and lasted up until the age of 12-13. Past that age football was gradually reduced to the occasional game during mandatory gym classes in school. Still, I LOVED playing that sport. Nothing so exhilarating and relaxing as just going for it during a game of football. 

After the age of 13 school work increasingly started absorbing ridiculous amounts of time. When I developed double vision at the age of 18 and underwent the misplaced surgery, leisure sports went down the drain except for the occasional run. Double vision is not very practical when it comes to ball games, or anything else for that matter.


It's been a little over a year since my diplopia started to subside after 5 years of constant double vision.  However, it's only recently that  the increasingly accurate positioning of my eyes is starting to 'sink in'. A month ago, spurred on by the WC merchandise machine, I bought a cheap football in the supermarket thinking it'd be fun to do some oculo-motor 'cross-training'.

Have a look at what happened after a week or two after messing around daily for an hour or so. The video builds up towards the end and the last thirty seconds are pretty neat even though I say so myself.

Not bad in light of my history of strabismus (surgery) and the fact I don't even have stereo vision yet! Please allow me to explain why this is happening at this point in time.

"It is important to understand the many aspects of vision to be examined, and to gather quality data on each patient, as the visual system is a covert system, where the process and outcome are evidenced not as “visual”, but as motor or verbal outputs." - Vision Rehabilitation

As you might have noticed from previous blog entries, I've been putting a lot of work in refining my eye movements. By this I mean getting them to be more precise and consistent as opposed to spastic and erratic. In my case the first phase of strabismus rehabilitation can be described as overcoming oculo-motor restrictions/palsy. The way our eyes move might just be the most important part of seeing and most people don't even realize it. Depending on the strabismic patient and whether or not he had surgery this will take some time. However long it takes, it has to be done in order to progress to more advanced levels of binocular and visio-motor integration.

 I've NEVER been able to effectively juggle a football before, let alone 33 kicks without it touching the ground. The only reason why I can do this now, after years of not playing, is that I can keep both of my eyes focused on the ball. Even though I don't have full blown stereoscopic depth perception yet, my brain already makes these subtle trigonometry inferences about its position. That never happened before. The first 17 years of my life I was suppressing one eye, then I lived through a couple of years of double vision and now the eye alignment is starting to be incorporated at a cortical level. This is an aspect of binocular vision which is evidenced as motor output as I do not SEE any depth yet. Cool, right?

This was again confirmed in my VT session (#74) today. I had a 90 to 95% success rate deciphering the relative position of objects while viewing tranaglyphs and polarized vectograms by 'grasping them' in midair. It's unbelievable! I was just staring at my hands thinking 'magic hands'. Magic brain rather! This depth perception stuff is creeping up on me silently!

Finally my brain is slowly starting to make subconscious inferences about
depth based on the input and position of both eyes!
If your brain doesn't do that, you'll end up like this physicist.

In light of that, these new found football skills make sense. The target is pretty large and it's a bit further than the distance range used for reading. Thus it requires less accuracy and less converging than reading. A nice stepping stool. This is good news as my optometrist said that this kind of motor feel for depth often precedes the actual seeing of depth.


My Dutch VT friend Yvette used to be horrible at catching things. This, to her own surprise, improved dramatically after working on her binocular vision skills for a year or two. She now says 'I can see the hole in the Frisbee and actually catch it'. When she, unrelated to her DIY VT efforts, enrolled for a course of slack-lining (walking a tightrope), one of the exercises was to catch things while keeping balance. 'Even though I was shaking like hell and did not find a stable balancing position, I was able to catch everything. Now I can also catch with my left hand, even without looking directly at the object.'

This is remarkable for a clumsy strabby who was never able to catch anything before! As she already acquired some stereovision, this is something to look forward to. Nevertheless, the benefits of stereovision are much broader than being able to catch stuff. From what I read, it's a whole different way of life. For now the punch line is that I'm making good progress and the best is yet to come. We ain't seen nothing yet!

Additional reading on vision, the brain and football

If there are any football clubs out there wanting to sponsor my
strab rehab or you just like my blog... ;)

Saturday, June 21, 2014

The accommodative rock demonstrated

This is a video of me performing an exercise called 'accommodative rock' or a version thereof. You need a tiny letter chart to hold in your hand and another big letter chart on the wall in front of you. The exercise simply consists of alternately reading a letter from the paper in your hand and then a letter from the chart on the wall.

That sounds pretty easy and straight forward but with a history of strabismus (surgery), it isn't. Both stimuli require very different responses from both they accommodative as vergence systems. It's taken me years to just be able to produce these responses correctly but achieving both states isn't enough. You need to be able to 'rock' back and forth between them in an automatic, fluent motion without losing too much time, juice or concentration! Ideally it should not require one's full attention merely to execute the physical movements. My goal is to be able to do it well and without effort. Have a look at my current level when executing the accommodative rock.

What can we say about this aside from the fact that I need to work on my decorating and directing skills?

I gradually move the handheld paper to the right. Maybe because I get tired, maybe because it's easier to view it that way or both. That compensating behavior has to go.

- Wandering OS. The left eye is my inferior, 'lazier' eye. To remedy this lack of speed and control it could be appropriate to execute this exercise also while patching one eye. This way I strengthen each eye individually as well as the team.
To specifically stimulate my left eye or the brain activity associated with it, I already apply a blurry filter on the right lens of my glasses each morning until I get tired. I prefer 'blurred out' patching over full occlusion because it still allows sunlight to enter both eyes.

- The far away target needs to be on the same height as your face, not up. On this occasion my webcam was blocking the view but normally it'd be straight ahead to stimulate near and far viewing at the same height. The shift to superior gaze is an extra hurdle we want to keep for later.

- Needs to be executed more slowly to solidify skills.

- You can't see this in the video but when looking at the nearby letter chart I get double vision midway of the exercise. In this case the misalignment was vertical. The print is very small and requires very precise eye movements. Halfway I was already tiring and my accuracy was getting sloppy. This kind of motor imperfections will ultimately be eliminated entirely.  I know this because I've seen things improve again and again over the last three and a half years. Refine, refine and more refining.One day I'll simply wake up with a rock solid gaze.

Also watch:
- Instructional video with more information on how to execute the 'accommodative rock'
- You want more evidence? I'll give you some evidence right here!

Also read
- VT and eye movements

Thursday, June 5, 2014

Can standing on your head result in better vision? Please read before you go around breaking your neck.

"My lazy eye turned on on New Years Day, I don't have amblyopia anymore and I do have depth perception for the first time in my life. The whole world is more beautiful than I ever could have imagined. I will be 70 years old in the fall. 

Last June I started standing on my head every morning as a fitness exercise. It wakes up and tones the muscles all up and down my body, why not my eye muscles, too? I can't say for sure that's what turned the eye on, but try it. Even if it doesn't fix your eyes it will still be good for your body.

Bill Johnston."

LOVED this story! A seventy year old man standing on his head and boldly going where he'd never gone before. Hell yes. I'm not implying we should all go standing on our heads to recover our vision, much less do I want to be held responsible for any aneurysms resulting from it. I did want to explain why this, however strange it might sound, is a totally reasonable quote from a neurological standpoint. I'm sure most doctors will already be getting in line to say there is no scientific basis for any of this but that's just because they are not interested in looking for one. In the early days neurologists went around calling synesthetes crazy, whereas we know now there are very valid neurological explanations for eg. seeing sounds and hearing colors!

So why might standing on his head have contributed to BJ's visual recovery? Because it works on the integration of (what I randomly call) the holy trinity of Vision Therapy: (eye) muscle tone, visual input and balance.

1. (Eye) muscle tone - Proprioception
Standing on your head radically changes the demands for muscle tone and no muscle in the body is exempt from this. Everything has to be re-calibrated which might induce lasting changes and more flexibility in the  contraction of muscles. Your eyes don't move in isolation and shouldn't have individual agendas. Ideally they move seamlessly and harmoniously in accord with the rest of your body. This daily re-calibration might contribute to this overall effect.

2. Visual input
Standing on your head puts your worldview upside down. That reminds me of a study I read about earlier.

"Incredible plasticity in the adult visual system has been demonstrated in psychology experiments by application of inverting prism in normal adults. Initially when wearing these prisms, the world appears upside down and backward. However, after wearing the prisms for several days, the world returns to its normal appearance, demonstrating the amazing plasticity of the visual-perceptual apparatus, as well as the vestibular-ocular reflex, which must also invert. Upon removing the prisms, the world is again, upside down and backward until the visual and vestibular systems reorient." - Vision Rehabilitation

Thus standing on your head taps into the same measure of adaptation and will enhance visual plasticity. This change, this call upon action due to frequent (daily) new environmental demands, might have reinforced the connection between the visual system and vestibular system (sense of balance). This might have created the need for his vision to become more binocular and in turn activate the 'lazy' or amblyopic eye. Contrary to popular believe amblyopia is not so much about the reduced acuity in the 'lazy' eye as it is about reduced overall SPATIAL vision. Amblyopia is a disorder of spatial vision first and a visual acuity disorder second. Integrate the amblyopic eye into the binocular team using the 'vestibular back door' and the acuity will catch up as a consequence as happened in Mr. BJ's case. Nothing we do in life goes without neurological consequences.

3. Balance - Vestibular System
Sense of balance can be the 'secret' VT weapon spurring on our binocular vision to get better in order to successfully cope with a balancing assignment. Standing on your head clearly puts your vestibular system to the test and is similar to the use of yoked prisms in VT. Yoked prisms also work on the three factors mentioned here. They shift the perceived image in a certain direction changing visual and muscle tone feedback. This makes it considerably harder to move through space and maintain balance. Coordination of movements and sense of balance are highly dependent on steady visual input so messing with that input will result in a challenge. I'd say standing on your head can compete with yoked prism training. Likely, it's even harder! Go seventy year old Mr BJ!

In short, standing on your head is a great way to integrate these three essential elements needed for good vision. I would say however it is something for the later stages of therapy, if at all. Standing on your head is not for everyone but  there are definitely compelling reasons to believe this kind of gymnastics contributed to BJ's visual rehab. In this case, the underlying neurological and environmental conditions were such that standing on his head  further integrated motor and visual skills and took Mr BJ from monocular vision to stereo vision. Brave new world!

Want more of this? Support the blog by donating!