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!

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.

Mark B, strabismic pilot with eyes on the skies

Around a year ago I met Mark B. through our DIY Vision Therapy Facebook group. Every so often he'd post a picture of a little airplane or an air field on his Facebook profile. I thought he must really like planes but since he was strabismic he probably doesn't fly them himself. Turns out I was wrong!

MICHAEL: Hi Mark, where do you live and how old are you?

MARK: I live in the Brittish midlands, in Redditch more specifically. That's just south of Birmingham. I'm 39 years old and will turn 40 this year.

MICHAEL: When did you develop strabismus? 

MARK: As far as I know it's congenital, although the term "strabismus" is relatively new to me. Growing up it was simply a "lazy eye" which was "treated" with eye patches. The patching was a regiment of forced reading with one eye. I don't think the patching did anything to align my eyes and improve the strabismus as such. At the time I didn't really know why I was doing it either. However, clearly the patching helped me keep vision in both eyes (avoiding amblyopia which is another relatively new term for me) so I'm grateful for that!

MICHAEL: So just to be sure... You never had eye muscle surgery, right?

MARK: No, the patching happened around the age of 5 or 6. Then, I can't remember exactly, maybe around 6 or 7 I had a few hospital visits and had lots of tests. They wanted to do eye muscle surgery but I was horrified and refused!  Over time I learned to control my eyes so they looked straight(ish). On the other hand, I also learned to suppress vision in one eye and developed a distinct head-tilt. I'm glad I never went in for the surgery. My parents were cool with backing out of it and never made a fuss about it.

MICHAEL: Clever kid, good for you! Did you have a hard time academically? What did you study?

MARK: I do remember when I was very young, reading was very difficult for me. I had above average intelligence and a very inquisitive nature but I struggled to read words as they jumbled all together. I would lose my place when moving to the next line. Over time, my reading got better as I learned (as I now realise) to suppress the image from one eye. At school I studied Science and went on to study Physics at university.

MICHAEL: Cool, what kind of work do you do currently? 

MARK: I'm currently working for a water company. It's a great job. It takes me to a lot of different places and I meet a lot of interesting people.  I work as a planning and scheduling manager - I've got groups of people dotted around the place who organise crews to go and respond to customer issues and make sure we maintain the pipes and overflows so we don't cause pollution. There's a lot to keep me busy!

MICHAEL: Sounds like an interesting and useful job! Water is important. How then did you get involved in aviation?

MARK: I started flying a few years ago - just a lesson a month which was very slow going. I've always liked planes and the idea of flying. It was my wife who suggested I should start flying lessons. I never really believed I could afford it or have the ability. I trained for a few years and got my private pilot's licence last year.

MICHAEL: That's awesome! What a supportive wife you have! Did you have to pass some sort of vision exam to obtain your licence?

MARK: To get a private pilot's licence you need a class 2 medical which involves a reasonably thorough medical examination by an aviation doctor including a "routine eye exam" (basically medical history, no "abnormal" eye conditions, a reasonable level of visual acuity and colour vision although the latter only restricts night-flying).

Last autumn I got the crazy idea of pursuing a career path in aviation (commercial work or instructing) but for that I would need a class 1 medical (thorough examination including very detailed ophthalmology exam, cardiogram, audiogram, blood tests etc.).

I spent a day at Gatwick airport doing this but failed due to strabismus. The guidelines for a pass on the vision exam are:: -

(1) At 6 metres:
2.0 prism dioptres in hyperphoria,
10.0 prism dioptres in esophoria,
8.0 prism dioptres in exophoria;
and
(2) At 33 centimetres:
1.0 prism dioptre in hyperphoria,
8.0 prism dioptres in esophoria,
12.0 prism dioptres in exophoria
 should be assessed as unfit.

MICHAEL: I guess they placed prisms in front of your eyes to elicit certain reactions and those were your limits or something...

MARK: I failed due to 8 dioptres hypertropia . My eye positioning was not fixed and would change all the time, even during the measurements. My eyes were just out of my control! They also said it would be very unlikely that I would ever be issued with a class 1 certificate. Nonetheless, at this point I was allowed to renew my class 2 medical (fit to fly - hooray!). That was when I finished my private pilot licence course in Feb 2014.

MICHAEL: It's too bad you were assessed as unfit for a class 1 certificate! Nonetheless, you seem to be endowed with an analytical mind and can do attitude. A problem needs a solution, right? How did you discover VT?

MARK: I think I learned about VT just by searching the web for 'strabismus cures'. I did a bit of research. I went looking for real evidence on websites that they genuinely viewed Vision Therapy as a serious and effective branch of optometry.  I have also seen some websites advertising VT as some kind of miracle cure or pseudoscience which put me off... Anyway, I found several good websites and eventually I also found your blog!

MICHAEL: I always love to hear that people find my blog! Did you ever read Fixing My Gaze? 

MARK: I did, it is a fantastic book! I really like the way it relates to Sue as the person and how she feels and relates to the world rather than Sue solely as the objective scientist. Definitely gave me hope despite years of dogmatic medical opinion that there is nothing that can be done with strabismus apart from cosmetic changes through surgery!

MICHAEL: When you first found out about VT you experimented a bit on your own, right? 

MARK: I did try some VT stuff before I started formal VT appointments but this caused me a lot of frustration. I think I was over stretching myself and trying to work on alignment and fixation without considering the basics like muscle control, attention and posture.

MICHAEL: Here are some of your group updates from around that time: 

January 21st, 2014

"Had an interesting couple of days. I'm experimenting with different things myself at the moment before handing over money to somebody who says I will never see in stereo.

The anaglyph Tetris is going okay but it's hard work. I'm still not fusing both images into one so it's like trying to guess how many columns to move the piece to land it. Interesting though, I thought my left eye wandered upward but it moves slightly to the right as well! I know it's helping me overcome suppression but it is hard!

I'm having much more fun trying to view 3D anaglyph (blue/red) photos, I'm finding that if I relax my eyes and un-tilt my head (I have a head tilt), I get fleeting moments of 3D vision. I tried to explain to my wife that it's like suddenly looking through a piece of glass in front of your face and everything looks beyond or in front of that piece of glass. Everything looks a lot clearer and sharper as well. Those fleeting moments are quickly lost but will hopefully build up.

I'm getting brief moments of stereo vision in every day life as well. They're few and far between but getting more frequent. This is going to take some serious time but I believe I will get there!"

March 26th, 2014

"Last week I felt I was getting somewhere. I worked on some crossed eyes stereograms for a couple of weeks and started to see in 3D in the real world but it was short-lived! I just went back to flat images and vague 'shadows' of the eye that tends to suppress. I'm going to sort out formal Vision Therapy in the next few weeks... I can't do this on my own!"

MICHAEL: How did you find your behavioral optometrist? You seem to be having very good experiences with the practice you are going to.

MARK: I looked on Google. They are surprisingly hard to find! I think I ended up on the BABO (British Association of Behavioural Optometrists) website www.babo.co.uk. Fortunately I found a behavioral optometrist around 40 miles away which isn't too far. I went with Keith Holland and associates in Cheltenham as it looked really professional and they seemed to genuinely care about what they did. The vision therapist has been working in this field for many years and really takes time to make sure we spend our time productively and focus on the right areas (no pun intended). I really cannot praise them enough and really look forward to our sessions! It is difficult to gauge my own progress as I am, by my very being, subjective but I have really improved my visual range (i.e. movement range of the eyes), ability to focus on specific points and stereopsis when viewing stereograms. I see the Vision Therapist every month and I think I'm due for a review with the optometrist every six months. I have a long way to go but I've definitely got some momentum going here!

MICHAEL: Yeah, you also went in with some fleeting moments of stereopsis which is a nice starting point! I would sign up for that any day! Here are some more group updates you posted after you officially started VT. I always liked your updates as they are so positive and excited.

August 27th, 2014

"Well, I finally had my first appointment with a behavioural optometrist today. I was warned that I might get permanent diplopia (double vision) if VT breaks my suppression but I can't fuse images. That's just something that could happen. The alternative is living with the strabismus which I don't want to do. I should get some news next week about starting proper vision training!"

September 15th, 2014

"I started vision therapy today!!! It went really well. The therapist said that a lot of people in my position (i.e. late thirties) find out about VT and start a program having done a lot of research and having a good idea of what it is about. As it was the first session, we covered lots of different things.

One thing that surprised me was that there was emphasis on balance and perception of surroundings. It had something to do with re-wiring the brain and creating new neural pathways in order to accept 3D vision. For instance, for one exercise I wore a pair of prism glasses which gave me instant double vision (no suppression). I had to look at my hands in front of me (there were four of them) and we went through each one (numbered 1,2,3 and 4!) to make me believe each hand was real. I'm not entirely sure what the purpose of this was but I will ask next time - possibly starting anti-suppression?

Anyway, I've got an eye-patch and my own brock string with a timetable of daily exercises for next time. I'm working on balance (walking in a straight line with legs crossing in front of each other), eye stretching (patching one eye and fixating to the far ranges of the unpatched eye) to strengthen the muscles and to "convince" the brain that it would be good to start looking in places where I currently cannot, and a brock string. I'm trying to get the "V" shape. I'm sort of struggling so far but I will persevere! There was one brief super exciting moment where we had a go at a polarised stereo pair plate and I could "see" one circle "in front" of the other. I've had brief flashes of 3D before but this was quite controlled. Apparently neurons going into overload and building new pathways when that happens! Looking forward to more of that! Next session in four weeks!!!"

September 19th, 2014

"Almost a week later and I'm starting to really break things down. The brock string is great. It shows you how things really are. It gives instant feedback on whether both eyes are "switched on" and if you're really fusing/fixating on an object (rather than your brain telling you not to worry about it!). Doing big eye muscle stretching exercises every day. I think they're helping. I can "fix" a bead on the string after doing stretches. It's just going to take some serious repetition and practice. Onwards and upwards!"

October 14th, 2014

"I had my second VT session on Monday and we covered loads! I tried brock string with red/green glasses which really helped. It seems to help break the suppression as the two images are clearly different colours. I've now added those to my VT pack. We did some more balance work with prisms to alter my view point. We're working on centering my brain and body. My VT is big on looking at vision as a holistic sum of many parts, not just the eyes!

Did some more work on the polarised tranaglyph. I'm sort of seeing depth but really struggling without another reference point to compare it to. I've been given some homework to work on hand/eye coordination and estimating depth by threading a straw with a cocktail stick and to keep with the brock string.

A final thing we did was called the "Van Orden Star" which is a bit like a stereogram lensed viewer where you join opposite sides by drawing with a pencil to where you think they meet. I think it gives an objective visual representation of how you see the world (how your eyes are positioned, that is). One side seemed higher than the other which would make sense. We're going to do it again in a few months to see how I've improved (!).

In every day life, I'm suppressing less by fixating on objects with my eyes more rather than turning my head. This is bringing on some diplopia but it is completely within my control and is useful feedback on where my eyes are pointing and how far I am off. I'm sure my brain would prefer I didn't do this but it's tough.  It's going to have to adapt I'm afraid! I am getting regular flashes of "depth" also - very briefly but more often. I just need to keep pushing myself. Onwards and upwards. This VT stuff really does work."

ANDREW: Apparently you have some 3D vision and it's gradually getting stronger and stronger. It doesn't seem that you just suddenly *got* it. Some people mention 'layers of depth' in regard to object array auto stereograms without really seeing depth in every day life. It seems like it's a sort of low-level stereopsis. With higher-level stereopsis, I'd imagine that you would see depth exactly as you would Y and X dimensions. 

MARK: Yes, the depth I see is something I've discussed a lot with my Vision Therapist. I refer to it as relative depth as I can differentiate between different depth planes in a very real way. They seem nearer or further away. Nonetheless I really struggle with tying that up with their absolute position in space. I think judging absolute positions of objects and the environment by stereoscopic depth perception is a learned skill which most people learn throughout infancy. For us strabismics, however, it's another step in the Vision Therapy chain of neural learning.

ANDREW: Do you have still have strabismus, i.e. a perceptible misalignment?

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!
  
MICHAEL: Things seem to be moving in the right direction for you! That was October last year. How have things progressed since then?

MARK: Ever since I started formal Vision Therapy I've been making leaps and bounds of progress. It's been hard for me to judge as things don't happen quickly but I have regained a lot of muscle control and I have a better degree of stereopsis. For example, when I was first assessed, I was shown a stereoacuity test "the fly" which was just a polarized stereogram of a fly. I was asked what I could see and, with my alternating suppressing ways I answered that I could see two slightly different images - it depended on which eye I looked with. I had completely forgotten about this when I was shown it again a few weeks ago when I saw a fly with different levels of depth, it was very clear but I didn't know what the big deal was! These things creep up on you, I think I had been doing a lot of stereogram tests and failed to appreciate the progress I was making! For me, the results are not dramatic and immediate but do build up over time. I'm amazed at how little understood and acknowledged VT is in the medical community given that they estimate that 10% of the adult population has stereo-blindness due to vision alignment problems. Every time I have had an eye test they tell me that my vision is perfect, 20/20 and that I have nothing to worry about and nothing can be done except for surgery!

MICHAEL: How does Vision Therapy fit into your aviation activities and plans?

MARK: I am currently doing some more flying courses (flying on instruments, night flying) to keep the flying going while I go through Vision Therapy. Flying will always be fun even if I don't ever work in aviation. Nevertheless, I do plan to go back to Gatwick sometime and get my class 1 certificate and who knows where I'll go from there. I do intend to keep working my full time job for the time being but the eventual aim is to get a full commercial licence and train to be an instructor. I think I'll retire as a flight instructor in the Scottish highlands, taking people on pleasure flights. In comparison to my current job, flying is so much simpler but much more exciting and with a better view!

MICHAEL: That sounds like a great plan. It's good to have plans and goals to aspire to. It will certainly keep you motivated. Thanks for taking the time and good luck with everything you do, Mark! Onwards and upwards!

Looking back at 2014 and looking forward to 2015

I just reread my post from December 25th, 2013. It's always interesting to compare thoughts over time. Often we get lost in the day to day to remember the overall progress we have made. I remember being able to do some bar reading for the first time ever in January 2014. I also remember being able to do head turns without the view going double and shaky in May. This still isn't always the case, depending on fatigue, but that's when it happened for the first time. Stabilizing the Vestibulo-Ocular Reflex will be of utmost importance to complete this visual rehab process. Two major milestones right there.

These firsts produced themselves under controled circumstances and while maintaining a regimen including lots of rest. They need to be solidified but they are obviously good signs. I still face trouble reading and using electronics due to convergence problems BUT there is improvement. Improvement is what we are going for. You can't expect to directly go from being partially paralized to running marathons. It feels like I'm litterally completing a picture and filling in the holes, motorically and perceptually. Each year, since I discovered Vision Therapy, I have added or improved underdeveloped or damaged visual skills and it's compiling into something substantial. I hope all these elements will come together, integrate and anchor themselves through sensory fusion and hopefully stereovision the upcoming year. In the end it will have been worth every second. As the years go by I feel less shell-shocked and post-traumatic stressy and more grounded and armed with more adequate visual artillery to face the world and its challenges. If I can pile another year of improvement on top of that, who knows where that will lead me. I'm eager to find out and pursue that road. Usually the results always produce themselves but the timeline is always more extended than I'd hoped for. God, give me patience! :) Happy New Year!

It might have to be the next Christmas, or the one after that,
but I will get what I'm after.

VIDEO: Current convergence status + The 'time-of-day-effect'

For a previous post I uploaded a video recorded in December, 2011 and went on to compare it to a video captured in May, 2014. The images were self-explanatory and it was pretty spectacular! I recommend for anyone with strabismus to make videos of their eyes. It's great to monitor VT progress and, in doing so, keep motivation levels high. Adhering to that idea I made some more flattering videos.

In those earlier videos I converged on a pen. In 2011 I failed radically. In May 2014 it finally started to look like something you'd call convergence. Converging on a pen was just a way of demonstrating the problem because, in reality, just being able to maintain that static pose won't get you far in terms of every day visual activities. In other words, there's still a lot of work improving more dynamic convergence activities such as the tiny saccades needed for reading. While reading I have to do a lot of correcting my eye movements. These corrections drain your energy, up the frustration and visual confusion levels, diminish reading comprehension. Generally it just brings you down! However, that's very hard to get on camera... Those mistakes and their consequent corrections are now likely to be something akin to nano-millimeters, at least initially. From the inside these issues are very noticeable but not so much from the outside.

Because of this, I thought of a different way to register my remaining convergence issues by shifting the convergence frontier to the extreme. Instead of converging on a pen, this time I converged on the little nose supports of my glasses. Not a very natural movement but useful to elicit and demonstrate remaining convergence problems. You'll see that my left eye can't sustain this posture and drifts out towards the middle.

The first video was recorded around 6PM on December 11th, 2014. I was already quite tired when recording this video so the problem is very noticeable.

The second video was recorded around noon on December 13th, 2014. It was a Saturday so I was able to sleep longer. Sleep is an important factor. No perfect convergence either but a very remarkable difference compared to the first video.

Not only are these videos interesting as a record of my current convergence status but also a reminder that the time of day and fatigue levels can influence the results of a vision exam! Sometimes you do better or worse at the optometrists's office than is generally the case! Keep that in mind.

In an unspecified period of time I will post a similar video in which I will be able to sustain this kind of convergence without trouble.  Haaaa, one of the final frontiers in order to improve reading stamina and overall visual stamina. This is a big deal, people. A BIG DEAL! Back when I was a full-blown and manifest strabismic, I thought 'Convergence Insufficiency, how hard can it be?' but I admit it's a b*tch.

PS: It's my birthday! :)

Session 79: A short Aperture Rule update.

Recently a VT friend of mine named Pasquale asked me how I had progressed in executing the Aperture Rule ever since I wrote 'Doing time' two years ago. Last week I asked my Vision Therapist whether I could try the AR again to verify.

Two years ago I only recently started having single vision some of the time. Back then I was able to execute the AR up to level 4 (of a total of 12) both with the exo and eso settings.

Right now I am able to execute the AR successfully up to level 7 using either the exo or eso aperture. Not too shabby! Certainly when considering my Vision Therapist said that even people with 'normal vision' often have trouble going beyond level 9 or 10.  

Good. This is where binocular vision problems come to die a slow and painful death. 

The vestibular system and vision

I've been reading up on the link between vision and the vestibular system. It's been quite instructive to say the least. Of course it's annoying not to be able to align the eyes and have double vision while reading etc... However, there's more. It's very interesting how compromised eye movements, in large part due to eye muscle surgery, and consequently a compromised Vestibulo-Ocular Reflex are likely to be the biggest source of disability and fatigue for me personally. When going beyond my relatively low visual endurance limit, the sensory conflict between the visual and the vestibular gets exacerbated. It sometimes feels like being drunk and can even give me something resembling to a hangover later on. Not merely alignment of the eyes but also the integration of these ocular motor skills with the vestibular system will be crucial in terms of lasting vision therapy results and daily functionality.

What is the vestibular system?

- Peripheral
The term 'vestibular' comes from the Latin 'vestibule' which means room. This 'room' is located in the inner ear and contains a minute amount of chemical fluid. Its workings involve the detection of fluid movement by receptor hair cells in various differently oriented semicircular canals. Vestibular injury may or may not be accompanied by hearing loss.

- Central
The vestibular sense is often misunderstood or overlooked. That's because, for instance, there is no such thing as a primary vestibular cortex.

'There is, rather, a complex of cortical targets many of which remain difficult to understand. From the brainstem, vestibular signals reach a subcortical structure called the diencephalon. Tucked in between the cerebral hemispheres the diencephalon houses such important structures as the pineal gland, hypothalamus, and thalamus. Compared to the cerebral cortex the diencephalon is small in size but is very rich in nuclei for sensory, motor and limbic pathways. The thalamus is a central relay station for all incoming sensory signals excepting olfactory information.' - Vision Rehabilitation

Without going into detail, we can conclude this sense is for a large part located in the primitive,  reptilian part of our brain which houses many basic but vital functions. In fact, this sense is so essential to our functioning and well-being, that the vestibular nerve is the first fiber tract in the brain to begin myelination during pregnancy. This process starts by the last week of the first trimester. By the end of the fifth month of pregnancy, the vestibular organ has reached full size with ongoing myelination of pathways to the eyes and the spinal cord.

- Function
Whereas the anatomy and chemistry of the vestibular system itself are fascinating, its interaction with the visual system and other somato-sensory systems are even more interesting.

The vestibular system is responsible for
(1) detecting linear and angular head movement and head position in space;
(2) assisting gaze stabilization of the visual field;
(3) maintaining balance and postural control; 
(4) providing spatial orientation or perception of body movement.

The primary role of the vestibular system is to provide the brain with information to regulate posture and to coordinate eye and head movements. Proper vestibular functioning and integration with the other senses is of major importance to good overall health, optimal functionality and vision.

Link with vision?

'The vestibular system plays an important role in the generation of eye movements that compensate for head movements. Through vestibular nuclei in the brainstem, each SCC (semi-circular canal) is able to communicate with motor neurons of extra-ocular muscles to cause eye deviation in each canal’s own plane. This interaction is the basis of the vestibuloocular reflex (VOR), which stabilizes gaze upon an image or the visual world during head movement. If the VOR is impaired, loss of gaze stabilization is the result. For example, as the patient turns the head while walking an object in the visual field or the whole visual environment appears unsteady or “bouncing.”

Demer described the VOR as a “synergistic” interaction between the vestibular and ocular systems. Normal VOR stabilization is needed for “functional vision, and vision optimizes the performance of the VOR”. Dynamic visual acuity (DVA) plays a role in maintaining a sharper image on the retina, while the VOR steadies gaze during head movement. This interaction is called the visual vestibuloocular reflex (VVOR).' - Vision Rehabilitation

And in turn...

'Sensory receptors in the eyes provide important feedback regarding orientation of the body in space. In other words, where is the head in relation to the horizon? As discussed in Chapters 5 through 7, dysfunction in the visual perception of “straight ahead,” common following brain injury, can cause dizziness, disorientation, and imbalance. In the process of orientation, visual input also provides information regarding possible environmental hazards, barriers or avenues of escape. In the presence of impaired inputs from either the somatosensory (sensory projections from all over the body) or vestibular or both systems there is a strong dependence upon visual input. Defective input from one of the three systems (visual, proprioception/somatosensory, vestibular) may be compensated for by the remaining intact systems such that the patient is able to function, albeit with some discomfort and loss of efficiency. However, dysfunction in two of the three systems will result in significant disability.' - Vision Rehabilitation

Problems?

Even though the vestibular sense might often be overlooked by physicians, one will be made aware of its existence in case of dysfunction.

- Inappropriate nystagmus
'Spontaneous nystagmus, occurring when the head is static (still), is an indicator of acute peripheral vestibular loss. Nystagmus is often along the horizontal plane. Vertical or torsional spontaneous nystagmus usually indicates a direct injury to the brainstem. The cause of this inappropriate nystagmus is a direction-specific imbalance in the VOR as brainstem neuronal circuitry is activated. Inappropriate nystagmus may also be related to medication toxicity, such as some antiseizure medications.' - Vision Rehabilitation

Inappropriate nystagmus may also be provoked by head shaking and indicates an imbalance of dynamic vestibular function.

An indicator of inappropriate nystagmus of central origin, caused by brain dysfunction rather than dysfunction of the peripheral organ, is often the inability to inhibit nystagmus with visual fixation.


- Dizziness
Feeling disoriented, especially in dark areas, or feeling spacey, floating, rocking, or lightheaded. Dizziness is not always related to vestibular dysfunction but may indicate non-vestibular causes, one of which being visual disorders. However, when dizziness is mentioned, involvement of a vestibular dysfunction must be considered.

- Vertigo
Even though dizziness and vertigo are often used interchangeably, technically there is a difference. Vertigo refers to the illusion of movement, typically rotational, when no actual movement is observed. True vertigo refers to vestibular system involvement.

- Motion sickness
What causes motion sickness?

'There is a hierarchical preference to rely on visual input more than any one of the other two systems (vestibular, proprioception) involved in balance. Vision, as proposed by Bronstein, had a dominant role or “hierarchical preference” over proprioceptive input in the process of maintaining upright posture and balance. However, Mallinson et al. suggested that a “visual preference strategy” would not apply to some individuals who have an intolerance for any disagreement between visual and vestibular signals. Paige had previously called this disagreement between the two systems as a “visual vestibular mismatch” (VVM) and others referred to it as a “sensory conflict.” By 1996, the “sensory conflict” theory for the development of motion sickness had been accepted within the scientific field studying this subject.' - Vision Rehabilitation

- And more...
Balance problems, gait ataxia, ...

Of the top of my head I can think of two interesting cases I read about involving vestibular dysfunction.

In the book 'The brain that changes itself', Norman Doidge described a woman who felt like she was perpetually falling due to vestibular injury.   Her vestibular organ was damaged but her central vestibular processing capabilities were intact. We can't even start to imagine how she felt. It completely ruined her life. Until a certain Doctor thought of the idea to supply her brain with 'vestibular input' in a different way. He connected an accelerometer to a tongue outlet which gave her a certain signal depending on the direction towards she was falling. Through the mechanisms of brain plasticity she learned to ignore her vestibular organ and to stabilize herself using this new input stream. Somehow over time, as her brain re-calibrated, she became less dependent on the device and needed it less and less.

Another vestibular story was featured in Oliver Sacks' 'The man who mistook his wife for a hat'. A Parkinsonian, 93 year old, retired carpenter whose vestibular sense had become more and more unreliable started walking tilted over to one side without knowing it. His senses deceived him until he saw himself on camera. He was speechless. After this discovery he wondered whether he could apply the mechanism of a spirit level to his problem. He designed a pair of glasses including some sort of spirit level which he could then use to teach himself to walk upright again. Essentially he retrained his impaired vestibular system using visual feedback. At first it took a lot of conscious effort but later on it got easier and easier. Just like learning how to drive a car.

Psychological impact of vestibular dysfunction

'There are a variety of reasons why patients suffering from episodes of vertigo develop anxiety, depression, poor self-esteem, and a growing sense of disability. The fear of falling or the fear of heights is common. Concern for a sudden onset of vertigo and the loss of control in public venues often leads to avoidance behaviors or “safety-seeking behaviors,” as coined by Gurr and Moffat. The appearance of staggering, falling, and confusion may lead observers to believe that the person is intoxicated. The patient soon finds him/herself avoiding social events and staying home to avoid embarrassment. Physical activity is avoided for fear of provoking an episode.' - Vision Rehabilitation


Testing

- Static and dynamic balance testing. Dynamic balance tests require input from the Vestibulo-Ocular Reflex to stabilize the visual field and make rapid adjustments in posture. Dynamic gait, sit-to-stand, ...
- Dix Hallpike maneuver
- Bithermal Caloric irrigation test (COWS): spraying water in the ear. Check it out on Youtube. It's pretty cool.
- Comprehensive Vision Testing: gaze, tracking, binocular vision, perceptual, functional, nystagmography, ...

Please read Chapter 9 of 'Vision Rehabilitation' for more detailed information. 

Rehabilitiation of the vestibular system

Vestibular injury or dysfunction can impose dramatic alterations in a patient’s once active lifestyle. There will be occasions when medication can be helpful in the short term. Surgery is the rare choice. Therapists take caution when a patient has other disabilities (brain trauma, stroke, peripheral neuropathy, spinal conditions, and/or vision disorders), which may limit choices of exercises.

'A key factor in achieving the best outcome will be patient compliance. Education is the greatest tool used by a good therapist to engage a patient’s willing participation in what is usually a difficult treatment program. Between, both, the vestibular therapist and the psychotherapist the patient is assisted in understanding the basics of the dysfunction: Why symptoms occur; the emotional response; and how treatment should help. Initial treatment typically provokes unpleasant symptoms but feeling worse comes before feeling better. Another factor in achieving the best outcome involves adequate intensity and duration of the treatment program.

Progression of function is the best gauge for the effectiveness of treatment. The process of treatment involves strategies for adaptation and substitution by using other strategies, habituation (desensitization), and retraining of balance. As the patient is able, exercises are expanded to include cardiorespiratory conditioning. Goals of vestibular rehabilitation are to (1) optimize compensation in the balance system; (2) habituate abnormal vestibular responses to rapid movements; (3) reduce fall risks by improving balance and postural control; and (4) educate the patient.' - Vision Rehabilitation

Is it a vision problem or vestibular problem?

It's important to figure out whether you are suffering from a vestibular problem with a visual component or a vision problem with a vestibular component. For strabismics who identify with some of these issues, the answer is probably 'a vision problem with a vestibular component'.

That is why in the more advanced stages of Vision Therapy you are not only training eye movement. You are to stimulate your way towards overall sensory and thus vestibulo-visual integration. There's a million ways to skin that cat. Some of the things I do as vision therapy loading: walking, head turns while attempting to keep my gaze stable, walking a beam with yoked prisms, balance board, jumping on a trampoline, standing on my head, running, ...

When my vision tends to go blurry or double and I feel dizzy, it's time to take a break. I flirt with my limit, take sufficient rest and remind myself that sometimes you do have to feel worse before feeling better. Improving these elementary vestibulo-ocular skills does influence and improve more sophisticated and more cognitively taxing ocular motor activities such as reading. The ground is being prepared!

'The ticking time bomb that split my world in two'

About a week ago me and a man named Ryan Brooks had a thought-provoking conversation on my Facebook wall.  I had just shared my latest blog entry 'The margin of error'. He commented "I always find your posts extremely interesting. I had a bleed in the brain stem which has left me with double vision. This is how I see now."

That is not your every day Facebook comment but I knew the visual phenomenon he was talking about of course. As I'm always open to learning about how other people deal with visual brain problems, I asked him whether he wanted to share more about what happened to him. He was prepared to do so and I am happy for it. Even though our histories are different (developmental vs cerebral incident), we are talking about closely related visual issues and symptoms. Thank you for sharing your incredible story, Ryan!

I present to you, Mr. Ryan Brooks.

Part 1
RYAN: "I am 40 years old. I live in Newcastle NSW, Australia. I was an occupational health and safety manager in the mining industry and traveled the world to places like New Caledonia and New Guinea to name a few. I had only been home for eight weeks when the incident happened. Over a period of three months prior to the bleed I had experienced three separate dizzy spells and racing heart episodes but only lasted for about ten minutes. I attributed it to maybe anxiety due to my stressful job.

The brain bleed happened on the 25th of June, 2012 at 11.15AM, I woke up feeling great and drove down to a cafe on the beach for a coffee. As I walked down the beach to the cafe my vision started to blur and I felt a strange buzzing feeling at the back of my head near the base of the skull. I put it down to still being half asleep. I ordered a coffee and sat at a table outside watching the surf. The buzzing started to get worse. I started to feel like I had butterflies in my stomach and felt increasingly faint. I got up to go to the bathroom to wash my face. As I got to the door... Boom. Suddenly I felt as if pins and needles were penetrating my face. Down my left arm and leg I felt numbness as well as pins and needles. All this combined with a feeling of complete disorientation. I managed to stumble back to the front counter and said "Call an ambulance, I'm having a stroke." Then I passed out over a table. A short while after, I came back to and noticed no one was helping me. I was in a bad way. I remembered there was no phone signal inside so I got on my hands and knees and crawled out the front door. I laid on the path, rang my sister and told her what had happened and for her to call an ambulance. The people at the bar told my sister that they thought I was a drug addict having an overdose. My sister went absolutely ballistic. The ambulance arrived 20 minutes later and off to hospital we went. After some brain scans the doctors realized that I had a bleed in the upper mid brain, which is part of the brain stem. More conspicuously, by merely looking at me, they could see my left eye was turned in so hard towards my nose you could barely see it. "

Ryan and his daughter

 Part 2
"The official diagnosis was a cavernous malformation. In plain English this means that a blood vessel wasn't formed properly at birth and it took 38 years to wear out and rupture. In other words, a ticking time bomb."

MICHAEL: After the incident and the diagnosis, did they do something about that blood vessel?

RYAN: "They did an angiogram and injected ink into my brain which basically gave them a map of all the blood vessels in my brain and of the problematic area of vessels in particular. They didn't do anything because the brain area where it happened is very complex. The vessels in that area of the brain stem are the size of a strand of hair. Fortunately they were not arteries. Doing something to 'fix' it would entail too much risk. An intervention might kill me or give me a major stroke. Instead we opted for yearly brain scans. There's no guarantee it won't happen again."

MICHAEL: How did things proceed from there on out?

RYAN: "After four initial weeks of rehab for partial paralysis down my left side everything started to get back to normal. Sort of... Concerns regarding double vision as a result of the bleed and nerve damage remained.

MICHAEL: Can you describe your current visual situation?

RYAN: "The official definition of the visual dysfunctions caused by the brain bleed goes as follows. Bilateral asymmetrical superior oblique paresis, cranial nerve paresis with convergence retraction nystagmus and some myopia in the left eye. But I would like to try and explain what that really means from my point of view.

From the outside my eye alignment looks normal other than a slight turn of the left eye.  Yet from the inside that's a different story. When I look straight ahead the image of my right eye looks pretty level but the image of my left eye is on a 45 degree vertical angle.The left eye also has very bad torsion.

When I tilt my head up and down the torsion becomes worse.  I have vertical up gaze palsy and so when I try to look up my eyes wiggle. Notwithstanding, when I tilt my head slightly to the right it pulls the torsion nearly square. In that moment my brain relaxes because it almost feels like I have normal and steady binocular vision again. Sadly I can't sustain the binocular posture. It's like a stare and after five seconds my left eye starts to drift.

When I turn my head left and right the images split up and down so I have to patch my left eye. It is very hard after 40 years of normal sight to now have two separate images that 'do what they do'.

When I walk without the left eye covered, the image coming from that eye bounces. So when using my right eye, with my left bad eye covered, the eye's movement compensates for any head movement. The image stays stable and straight (proper Vestibulo-Ocular Reflex). On the other hand, when I close my good right eye and only have to draw on my left eye, the image inadvertently moves up and down following head movement (compromised Vestibulo-Ocular Reflex). Not only does the image move up and down, but it also tilts because of the torsion. It's quite nauseating and throws my balance out. If I walk with only my bad left eye open,  it feels like I'm walking across a very steep hill. The image just bounces around inconsistently.

I have also noticed that the color isn't as good in my good right eye. At night my right good eye doesn't see as well as my left bad eye. Everything is a sort of tinted darker when looking through my right eye.

When I close one eye, my vision feels quite normal. although I had to get used to the difference in depth perception. At night, when there is little light, it feels like my vision is back to normal which stops the headaches. That's the only time my brain isn't fighting to get properly aligned binocular input. Then I can relax.

Considering all the above, using my vision is a very fine balancing act."

MICHAEL: How do you make these example images? Do you use an app?

RYAN: "You are actually the one who inspired me to investigate the internet and thus coming across the apps to help explain what I see to other people. These are the two apps. My Doctor was very impressed with the idea of taking photos of what I see and simulate what I see as I move my head into different directions. The images shift when doing so. This way he can see exactly what I see."

MICHAEL: What kind of treatment have you been getting or participating in?

RYAN: "I have been seeing a strabismus specialist in Melbourne at the Private Eye Clinic by the name of Dr Lional Kowal. I had VT for 12 months. While doing VT I was also going to Melbourne every three months for examinations. The VT pulled my eye nearly back to its normal position but the double vision remained.

After that initial year of VT, I have had five correctional surgeries but none have been successful due to damage to the 3rd, 4th, 6th, 9th and 10th cranial nerve. Every time a surgery was done it had a negative effect on either the vertical or horizontal relative positioning of the images. Unfortunately after five surgeries, two of which were to undo previously performed surgeries which had made my double vision worse, I am back to square one."

MICHAEL: I'm just thinking out loud... You had the incident in June 2012. Then you had one year of Vision Therapy aka Visual Neurorehabilitation. That brings us up to August 2013. So you must have had five surgeries in one year? How did that go? You seemed to be making VT progress, albeit slow. Who proposed the surgery? What did the Doctor tell you about its effectiveness, risks and possible outcomes?

RYAN: "As the double vision wasn't disappearing mainly due to the torsion aspect of my case, the Doctor or Neuro-Ophthalmologist suggested surgery. They explained the risks. He was confident he could give me an improvement.

The first operation was performed on both eyes and made the double vision worse. Five days later that surgery had to be undone.

Another three months later I had more eye muscle surgery on both eyes while being awake using only the use of anesthetic drops. They placed a black letter T on the ceiling and also on the wall in front of me. He started with the left eye. Cutting and manoeuvring the muscle a millimeter at a time. Then he'd wash out the eye, take the eye clamps out and tell me to look at the T and ask if there was any difference. Then he'd sit me up and tell me to look at the T on the wall in front of me and ask whether there was any difference. My response was 'it has adjusted slightly'. So back down for more adjusting. This process went on thee times until he said he couldn't do any more. He stated that if he overstretched the muscle it was irreversible. Next we repeated the same process for the right eye.

It was an extremely stressful experience. I could hear my heart racing. I was boiling hot due to the lights and surgical blankets. To be honest, after you have had your eye ball cut open, the eye muscles cut  and then flushed out with water, the mix of blood and water makes your vision quite blurry. So any indication of what I was seeing was compromised and not really accurate. My eyes kept drifting as my muscles were cut, my vision was blurred and the environment was extremely stressful.

A week later after letting my eyes recover a bit the double vision was worse. Another week later I went in for surgery again in an attempt to undo things. Under total anesthesia this time.

Four months later, one more surgery was done to do some slight tweaking. I was completely under for this one. Whatever the result was, I was going to have to live with it."

MICHAEL: You said 'I am back to square one'. Do you feel the surgeries were just a useless exercise or would you say it deteriorated the situation? I'm asking out of genuine curiosity, not because I myself had a very bad experience with strabismus surgery.

RYAN: "Now it is more or less back to where it was after the brain bleed, although a little different. Looking back I'm glad we gave it a try because now I know that at least we tried. I put my trust in my Doctor and we came out the other side not having gained but not having lost much either. He was a wonderful Doctor and only charged me for the first surgery. All the other surgeries he put through my medical fund at a significant price reduction. That was an incredibly kind gesture and showed that he was more interested in my case than in my money. On top of that I was extremely fortunate to have wonderful friends and family who organized a charity events such as a dinner party, an auction and a golf day. They ended up raising enough money to cover my surgeries, anesthetist, flights, accommodation, check ups, glasses, lenses, ... That all amounted to 30.000 dollars. If they read this, I want to thank Brett & Gail Purcell, Nathan Palmer, Tim & Macushla Spencer, Chad Edwards, Leeanne & Jeremy Symes and many other friends and family members who were involved. I had been 14 months off work so without this bunch of phenomenal friends my treatment would definitely have been cut short. I'm immensely grateful to them all."


Part 3
"Nowadays I'm using a tailor made contact lens that looks normal but really isn't. The outer edges are clear so you can still see the colour of my eye but the area covering my pupil is completely blacked out. I had to have my pupil measured so it looks cohesive with my other eye. This means that I am basically blind in my left eye when I have the lens in. Well, not completely blind... I still get peripheral vision from my left eye as the dot on the lens is a little smaller than my pupil and pupil size is variable depending on light conditions. Therefore, I still wear my glasses.   When I'm not wearing my glasses, I have learnt to ghost the images of my left eye but after a while this gives me head aches. So back on go the glasses! Looking at me you couldn't tell anything is wrong. However, without my blacked out lens and my glasses the double vision still gives me constant headaches. .

In general, my life has changed considerably following my accident. I no longer work in the mining industry. I now work as a disability case manager and spend much more time at home with my beautiful daughter."

The margin of error

Interestingly, my strabismus was developmental since the age of three but in a relatively short amount of time I lost many of my adaptations (suppression, strabismic ways of eye teaming) to cope with misalignment of the eyes. First my suppression gradually declined because of life style, i.e. overly zealous studying, and then the way my eyes moved and alternated was abruptly changed through eye muscle surgery. This left me without any reliable adaptation to deal with my abnormally developed visual system.

So the only option then, is pick up the pieces and start all over again. My visual system seems to act as a binocular system that was disrupted rather than a visual system which developed strabismically. It has no real inclination, or possibility for that matter, to go back to monocular viewing, alternation or any of its other former ways. There's a strong incentive to use both eyes, and it's constantly trying to do so, with varying rates of success. It's a binocular system whose inability to move its eyes accurately is cramping its style. Because of its poor handling, my case more resembles strabismus which was acquired later in life through brain injury than that of a developmental strabismic equipped with coping tools safeguarding functionality.

The level of spasticity or lack of control when it comes to eye movement is fortunately declining. It has been declining for some years and every improvement is a win. As can be seen in previous video posts, it's getting harder to spot there is any problem at all! However, automation is the goal, not merely the ability to execute the movements using disproportionate amounts of attention and energy resources.

Despite already increased accuracy and speed, there is still a considerable margin of error when it comes to my eye movements. I can not entirely rely on solid binocularity yet. It's either right or not right, and if it's not right you need to waste extra energy on correction which could have been used for observation and interpretation of visual input. Another issue associated with the continual trial and error, and the exertion it requires, is the build up of tension. Because of the lack of eye muscle control, surrounding areas of my body (face, jaw and gradually the entire body) start to tense up. The efforts to keep my left eye in check and attempts to keep up binocular performance will often result in jaw cramps on the left side and headaches. In order to avoid such an escalation it's recommended to allow for a margin of error and try to cut the visual system some slack.

What activities allow for a margin of error?

Reading vs General Navigation

Given this larger than normal margin of error, I prefer to avoid situations which require specific eye behavior.and do not leave much room for error. An obvious example of such an activity that requires precise and infallible eye movements is reading. There's a number of different ways to read but they all require impeccable eye movement control. That's why reading with audio back-up is much more agreeable with me. There's more room for eye movement error that way.

In contrast, the general observation of a road, square or real life situation can be done using an endless variety of eye behaviors. Some are definitely more effective than others but you can still get around.  For someone whose eye behaviors start looking deceptively normal such activities requiring an accuracy level of 'approximate' are starting to be fine. It's starting to get less overwhelming, less out of control. More ocular control will be very welcome over the upcoming year(s) but it's already quite manageable.

Driving is actually easier than walking or running because my body and head stay more or less in position, especially on a highway. Because the road and the mirrors are much larger than the words on a page while reading, and driving is less cognitively taxing, my current level of eye control is okay for driving. In fact, driving is pretty calming as it allows for staring and the use of peripheral vision.

Individuals vs Groups

The difference between reading, general viewing of scenes and driving is pretty straight forward. Here's something which might be more unexpected, or maybe not. Perhaps people without eye muscle palsy experience this difference too. Meeting with one person is a lot more taxing to my visual system than meeting with a bunch of people. I don't look strabismic anymore so it's not about  appearance. Meeting with one person just doesn't allow for much of an error margin when it comes to eye behavior. When talking to someone you have to look at that person. That's specific. It's likely you will have to hold your gaze steady but every once in a while you have to look away. The social situation dictates your eye behavior and your eye muscle control system better be up to the task. Most people I know and enter in contact with are aware of my vision issues and if I do act a little more peculiar than normal and start staring in the distance, I just explain. No biggy. Nonetheless, I try to keep up the eye contact dance. After all, it's good practice! It's also an important means of communication but you need the physical eye fitness to do it. 

When meeting up with larger groups, there is more room for errors in eye movement. You can just listen to the conversation and stare randomly every so often. Attention is divided and you don't always have to look at the person who's doing the talking. It clearly also depends on how familiar you are with the group. An entirely new group in an new environment is a probable overload. I will have trouble moving my eyes to explore and keep up with the new situation, people and environment, especially over extended periods of time. Not much room for eye movement errors in that case because you'll preferably need your brain to deal with the situation rather than an eye movement deficiency. You're losing attention to something that should be working automatically.

Factors that decrease the margin of error

Short term

When I'm going to do something relatively visually taxing, which includes many daily activities in varying degrees, you want to have me well fed and well rested.

I burn calories like you wouldn't believe and when I get hungry my accuracy diminishes and errors occur more frequently. So I'm eating a lot of the time these days as my appetite returned after a couple of very stressful years. This has a double benefit. It more or less keeps up my visual performance in the short run and makes me look less emaciated in the long run.

Naps seriously improve my vision. Even an half an hour nap will seriously improve my visual performance for the night. Don't be a hero, take naps.

Basically I'm just a baby learning how to see. Now we know why they too eat and sleep all the time.

Long term

Current practice consists of finding ways to allow a margin of error while slowly crushing that same margin as time goes by. Sometimes it is not possible to avoid situations that are too visually stressful. Then I do have to hurt myself by pushing it too far, resulting in tension and headaches. But by minimizing the time I exceed my limit and by granting the visual system relative rest, the comfort zone slowly expands.

Eye control and eye alignment should be invariable but is, in my case, all to often variable. Invariable and reliable eye movement control is a great advantage when executing bottom-up visual processing (taking in new visual scenes and observing them) and top-down visual processing (combining stored memories with what is seen). Virtually any human activity employs these kinds of visual processing. Therefore, I'm very curious about the dormant potential that might be uncovered as the rate of movement errors further declines. Stereo vision, for one.   If I ever want to live a 'normal', independent life, there's no other way but to keep working on accuracy, speed and stability of eye movement.


Eye movement control and the use of glasses for hyperopes

It's still frail and not ready to be stress tested, but it's happening. As my gaze gets steadier and the margin of movement errors declines, there is less need for my glasses. As vergence gets easier, I can focus more on the accommodation aspects of visual training. Seamless interaction and collaboration of vergence and accommodation is crucial to obtain a lasting end result in VT. As I'm farsighted (+2.5 in each eye) this evolution could have been expected. The glasses are more a way of avoiding fatigue and thus gaze instability than a way of providing better visual acuity. In fact, I often have to look over them to read things far away. As gaze stability is maturing I actually see better in daily life without the glasses. Ultimately they will just be reading glasses for near point work. Sometimes it even has a calming effect to take them off, even refreshing in a way. I'm still wearing them daily but every so often I let my visual system have a go on its own. Even though my glasses are rimless, it feels different not to wear them. I can believe people have an easier time seeing 3D without glasses or with contact lenses. Glasses have a way of distorting light and possibly binocular vision. However, I'm not going in heals over head... They are a useful anti-fatigue tool while I acquire more eye movement control.