Sunday, March 29, 2015

Cheiroscope: video, drawing samples and implications

After a nice theoretical post, let's get down to the nitty gritty. How can we get a tangible look into how someone perceives his personal space? How can we determine inconsistent perception of space interfering with the construction of solid brain maps?

As vision writes spatial equations for the muscles to solve, cheiroscopic drawing is an interesting way to gauge the state of ocular motor ability and spatial vision. During cheiroscopic drawing, one's visual system is completely stripped of contextual aids. Broader context often helps strabismics to get around and complete certain tasks by circumventing proper ocular motor movement or spatial vision and by relying on sub-optimal, monocular vision adaptations and other senses. When using a cheiroscope none of that is possible. Your drawing hand and fingers HAS to take its cues from the eyes. The movements of the hand are based on the movements of the eye. If the eyes are positioned well, move together in a smooth and harmonious manner and can maintain a steady posture, you will succeed. If not, you will come up with an inconsistent and skewed drawing. It's that simple. A direct connection. No more adaptations, no more tricks, nowhere to hide from your visual shortcomings. It's a head-on confrontation with your visual limitations but also an opportunity to improve and to chart and compare that improvement over time.

I made a little, informative video about a cheiroscope that can be used at home. I apologize in advance for the constant movement of the camera. My video recording skills also need more work!

Here are some more of my practice run results produced by using that device (March, 2015). They are each of them unique and contain small mistakes. The variations in the drawings are variations in my vision and ocular stability. My vision is still volatile and unstable. Yet, it's a far cry from where I've come from years ago. This maze is very detailed and requires a fairly sophisticated level of ocular control on which to base your solution. Merely being able to try this exercise is already a triumph for me.

Let me show you where I've come from, going all the way back to February, 2011. For that purpose, I will be showing drawings made by me with another type of cheiroscope. This is a standup variation of the cheiroscope. It is called the Wolff cheiroscope named after Bruce Wolff, OD, who designed it.

Recently, at the VT office, we were comparing some cheiroscopic drawings I had made over the years. These pictures compare the results of the same cheiroscopic drawing exercise. The upper drawing was done on October 16th, 2012. The lower drawing was done on March 16th, 2015.

The relative position of the drawings is different because of different eye positioning. Also the quality of the drawing itself is markedly different because of improved ocular stability. In 2012 the left hand drawing was so inconsistent that the sun wasn't even staying her box. Hell, there was not even a clear box! And, as someone acutely pointed out, now the suns do have a smiley face!

What's even more startling is the fact that, on October 16th, 2012, I had already been in Vision Therapy for one year and eight months! Here are two cheiroscopic "Van Orden Star" drawings comparing February, 2011 to October 16th, 2012. The drawn lines should converge onto the highlighted fold. In the first drawing, in 2011, this certainly wasn't the case. I had a considerable vertical misalignment too.

Van Orden Star
Notice that, in the picture with the sun drawings, the upper drawing was drawn on the same day as the lower Van Orden Star drawing. This nicely demonstrates that improvement is relative. On October 16th, 2012, I was delighted about my improvements regarding the "Van Orden Star" drawing. However, the more visually demanding and detailed sun drawing exercise left much to desire. Now, another two years later, the sun drawing too have improved significantly and I will continue to go down this road of more ocular stamina and accuracy. The only thing one can do is to consider his current vision status and keep on stacking incremental improvements to eventually get to a better place in the future.

My primary vision therapy goal is not stereo vision. Stereo vision seems to be a combination of various basic vision skills. Overcoming the crippling legacy of strabismus surgery, which has thoroughly destroyed already ailing basic vision skills, is my primary vision therapy goal. To be specific, I need smooth tracking, reliable saccades and a stable vestibulo-ocular reflex. When I accomplish that, I'm golden. From what I hear, stereo vision will be a nice bonus on top of having these basic visual skills. These basic visual skills by themselves are pretty awesome too though! Without eye muscle surgery, I would already be seeing in stereo! However, as the cards have been dealt this way, these extra hurdles have to be taken. There is no other way.

Me and my Vision Trainer summarized the current situation as follows. "No one would have thought you would have come this far when you walked through the door, more than four years ago, but now you possess the basic visual skills. You can see through both eyes, you start having fairly good eye motility, you have some fusion in polarized targets and you can even figure out depth in tranaglyphs with a reference object like your finger or a stick! You have all the ingredients and now have to go a little furter and combine them into a good menu." 

The only missing ingredient is more time and work. I can do that. The cloak of subdued dysfunction is slowly lifting itself. I have mentally prepared myself it might take until January 2017 for me to reach workable levels of vision. After six years, I think, this Vision Therapy thing will start to lose some of its charm. Hahaha. Cheers, everyone!

Saturday, March 14, 2015

The visual system's important role in figuring out where you are

Developmental strabismics often learn how to suppress sight coming through one eye. Many times they even learn how to alternate between both eyes. This is a useful short term neural adaptation but has many disadvantages in the long haul if not corrected. Having been, and to some extent still being, an alternator, I know how it works in practice and how it feels. If feels like you can shift between two ways of seeing. You are not only switching between your physical eyes but also between two viewing positions in your mind. You litterally have two "mind's eyes". When paying attention to this weird ability and supposing your head/body is a vehicle you are maneuvering, it feels like you can change the driver's seat's position. One moment you are in a normal car. The next moment you are in a Brittish car. You can shift what is called your visual midline (visual midline shift). When I was younger even colors used to look slightly different depending on which eye I was using! I remember when I was fourteen asking my mom: "When I switch from one eye to the other I sometimes get color changes. Do you also get that?". Reasonably enough she didn't really understand what I was talking about and had a disturbed look on her face!

In developmental strabismics the act of alternation is often a subconscious one. Because we developed this way we can usually apply it to our benefit as much as possible. It's not optimal but if you master and control it, it can be manageable. For me problems started occurring when, firstly, this learned visual neuro-adaptation started to unravel by itself due to external pressures (because it is not an optimal nor stable neural equilibrium).  Secondly, these problems were aggravated when the correspondence between how my eyes moved physically and how my neurology worked was radically disrupted through eye muscle surgery. That is why the first couple of days after surgery I even had to relearn seemingly simple acts such as keeping balance and walking. On the surface I learned quickly but a lot of extra unnecessary baggage had been added to tasks of daily living. I did my best to pick up the pieces and held my own for a couple of years but ultimately it was not possible to just forget about the problem and live a normal life. Untangling this neural and physical dissonance is a work in progress.


That is why following passages taken from the book Vision Rehabilitation strongly resonated with me. These can be found in Chapter 4 on Spatial Vision, written by Robert Sanet and Leonard Press.

"While walking, patients with ABI may demonstrate a shift in visual midline and altered gravitational sense termed visual midline shift syndrome (VMSS). These patients demonstrate balance impairment and associated motor dysfunction, including leaning, falling, or veering to one side during mobility. VMSS can have an immediate and dramatic effect on the motor dysfunction. 
The sense of awareness of one’s position in space is predicated on what has been referred to as “the invariant.” Without having a stable frame of reference of self, it is impossible to organize space efficiently and accurately. As an example, consider what it would be like to find the location of a specific place on a map using only the coordinates “two miles west and one mile to the north.” One cannot derive the answer without knowing the initial piece of information: “From where?”

 The invariant provides a stable frame of reference upon which we build spatial constructs. The mental representation of space, and perception of straight-ahead body orientation, are related to a number of internal reference frames, including visual, vestibular, proprioceptive, and tactile information that allow us to build accurate spatial maps. That is to say, the brain orchestrates movement using a series of internal models, maps, or schemes of external reality. Even before initiating the movement, the brain has already taken the visual information, anticipated the consequences of the movement, and formulated a series of motor actions to accomplish the goal. The antigravity system, therefore, relies on the integration of many neurological processes, principally as follows: 
- Visual system input that aids in the determination of vertical and horizontal frames of reference, and the perception of self-motion that comes from optic flow patterns across the retina. 
- Vestibular system input through the otolith and semicircular canal systems of the inner ear give information about head position relative to gravity, and changes in acceleration and deceleration. 
- Proprioception system input from the stretch receptors in the muscles that give information on body position.
Visual input to the vestibular and proprioceptive systems that direct movement, such as when adjusting balance or moving the body and hand to grasp an object or to catch a ball, is due in large part to subcortical “unconscious” visual pathways. The automatic, unconscious visual prediction and computation that supports motor planning and execution of accurate motor movement is often disrupted when patients experience ABI. This results in visual-spatial confusion and inaccurate visual guidance of motor movement."
This short clip by the BBC nicely demonstrates how disrupting changes to visual input can be for balance and motor ability.

I particularly like the concept of having a stable frame of reference of self in relation to the environment constructed upon various sensory streams of information referred to above as "THE INVARIANT." Vision plays a crucial role. Simply put, the visual system has four essential questions to answer:
1. Where am I?
2. Where is it? (an object or objects of interest)
3. What is it?
4. What do I need to do or say about it?

If that primary sense of awareness of where one is in space (the invariant) has become variable because of conflicting visual information due to for instance eye teaming difficulties, the answer to the first question has been compromised. If the invariable becomes variable, spatial uncertainty is compounded. This will have far-reaching effects on the visual system's ability to answer question 2 to 4. This interference and uncertainty will negatively impact the ability to oversee situations, interact with objects or find relevant information. Secondly, it will also compromise movements, memory, verbal ability and might cause serious fatigue and mental confusion. In short, without controlled and stable visual input to the brain, the ability to interact and build proper spatial brain maps suffers greatly.


To get back to my own story... Nowadays my, what is supposed to be, invariant is all too often variable and this has a profound effect on my ability to function. I am physically strong but this leak in the system can throw me off balance and drain my energy without mercy. I like to move but I do it in settings where I can easily retreat when needed. Over time my variable invariant is getting more fixed and coherent. When I have good moments and have relatively high amounts of ocular control, I can see abilities and talents I knew I have had all along flaring up. If I can get my invariable to be invariable more often and hopefully indefinitely, the sky is the limit.

One example of this is a basketball video I recorded a few weeks ago on "a good eye day".

This is pretty good for having no stereovision.  However, I cannot play like this consistently. Same goes for reading performance or any other kind of performance. It depends on whether I have good or bad ocular control that day or that moment. As optometrist Myron Weinstein once said: "Vision writes spatial equations for muscles to solve." Can my brain rely on the visual and proprioceptive input provided by my eyes?  Isn't it too exhausting to get my eyes in line? Those factors will determine how variable my "invariable" is at that moment and how well I will perform.
"We are never tired as long as we can see far enough"  ,- Emerson
Fortunately I know I can improve indefinitely, even with damaged eye muscles, and I will. As there is no other option but to do this rehabilitation thoroughly, I should not settle for damage control but I should try to unify these two alternating monocular ways of seeing into one coherent binocular system. This in turn will contribute to my body's sense of position, motor abilities and my ability to construct brain maps of any kind.

If you are interested in learning even more about strabismus, suppression and brain maps, I had a first attempt at making a watchable video tutorial about this topic. Enjoy!

Tuesday, March 3, 2015

Jaw clenching, Vision Therapy and earthquake resistant structures

Personally I learn a lot from reading/listening up on vision rehab and anatomy but I learn just as much from having conversations with other strabismics. I think it's a practice that could be useful to anyone with any problem. Don't compare yourself to people with a very differing, in this case neurological, background. Learn from people who are similar to you and dealing with similar day-to-day problems. What follows is a blog post constructed on this type of conversation.

PASQUALE: Hi Michael, in many blog entries you mention jaw clenching. I too have said that I engage numerous facial muscles while I try converging and diverging at different targets.  It feels like the brain is recruiting other muscles because it still hasn't figured out how to properly use the eye's extra-ocular muscles.

MICHAEL: I always think of it like learning how to do something with your left arm (unless you are left-handed). First you use your entire arm, often in a contorted way. Then you move on to more specialized movements of the joints and ultimately you can do things smoothly having very fine control over your arm, hand and fingers. Theoretically the potential for improvement is limitless.

Let's transpose this to the visual realm. At first, when trying to accomplish a visual task, you are doing it very clumsily and inefficiently. Your brain is trying to accomplish a task which requires fine ocular motor skill but it's not succeeding because of a lack of (lasting) control. Because many of us are hardheaded we redouble our effort and adjacent regions and resources like facial muscles are drawn into the process to little or no avail. Not good. Instead of redoubling our effort employing a very limited set of visual skills we should go back to the drawing board and improve and multiply our skills. Technique is more important than 'brute' force.

The visual system involves six of the the twelve cranial nerves. That's a lot of guns to fire and potentially misfire. When I experience jaw clenching after too much reading or just a visually or otherwise stressful situation, that implies I've gone beyond my current visual skill level and I need to back down.

Trigeminal nerve - 5th cranial nerve

PASQUALE: Have you figured out exercises that eliminate engaging other muscles except for those needed to coordinate the various components of the eyes.

MICHAEL: Well, any activity that encourages 'the eyes', meaning the appropriate muscles and neural processes associated, to do the work without recruiting other muscles. That implies not going too far beyond your current skill level and paying a lot of attention without getting frustrated. For me it means slowing down and lowering expectations while gathering finer motor control. As long as my jaw doesn't clench, I'm in the safe zone. Once I start hurting, I'm overdoing it. It's not always easy to be patient and sometimes there are just visually stressful tasks I have to deal with. Then I'm tired, dizzy and in pain.

When thinking about this problem I'm reminded of something I learned about earthquake resistent structures. There's no such thing as a completely earthquake resistent building but you can improve a buildings capacity to withstand external shifts to a large extent. There are various approaches you can adhere to when going about the seismic retrofitting of a structure.
- You can increase the global capacity of a structure. (strengthening)
- You can isolate the foundation so the structure can shake on it. (partial flexibility)
- You can impose intelligent structural changes. Structural vibration control technologies minimize forces and deformations. (flexibility)
The last option implies that various individual parts of the building can move or flex allowing for shock absorption.

Vision Therapy is akin to a seismic retrofit for the visual system. You make structural changes in how it works and learn how to control and flex individual parts. You learn to lean into a quake rather than stiffening up.  That way you can withstand more external demands, with reduced energy drainage and avoid collapse of the structure/system.

For me, eye teaming remains a big challenge but I'm getting there. A related challenge is to gain more independent control over vergence and accommodation, i.e. taking on any binocular stance while manipulating my eye lens as I please. Either component should have limited effects on the other one's performance and there should be a certain ease in doing this. Just like using indivudual fingers while playing the piano.  An increased 'isolation' of these visual components gives more freedom of movement. To continue the piano anology, you'll be able to play 'visual Mozart' instead of just hitting the keys indiscriminately with all fingers at once.

As far as particular exercises are concerned, there are plenty of options to choose from if you understand the underlying principle. Magic eye stereograms, prism/spherical flippers, Eccentric Circles, Aperture rule, even just playing freely with your vision, ... Many VT practices are grafted on this idea one way or another. They are looking to improve smooth eye teaming, lens focusing and then increasing skill level by adding more activities (balance, body coordination, cognitive skill, ...).

In that respect, I particularly liked a quote from the interview I did with Mark last month. It illustrates this point very nicely.
MARK: I still have strabismus but I have a greater degree of control. The reduced suppression helps. I can line everything up that I need for stereopsis (fixation on an object, in focus, no suppression, awareness of peripheral vision etc.). It can be an enormous effort but it's like any other form of learning. Repetition is the key and progress, however slow, will be made!
The only catch 22 when talking about all this 'control' is that you won't necessarily attain it by going about this like a control freak. Be relaxed, patient but determined.

One month later... 

PASQUALE: It has taken me over eight months to finally feel that my brain can move my eyes with better coordination without trying to recruit a battery of other facial, non ocular muscles. I have gone through an entire slew of other muscles including those around the temple region, jaw, even moving my ears. The worse was when I actually felt my upper jaw putting tremendous stress on my entire skull as if trying to separate one from the other. I have to say that I see more positive progress now that my brain isn't trying to move my eyes through the recruitment of all those other muscles.