Monday, January 26, 2015

When you hit a wall and can't push through it, erode it

When you hit a wall and can't push through it, erode it.

"It's always impossible until it becomes inevitable." - Jeffrey Sachs 

So far I've already reached some major visual goals I set out to achieve. Good! I know more or less how this process works and how real unexpected change can and does happen over time. Good! The downside is that the time table always turns out to be much longer than I'd hoped for. Nevertheless, results do materialize. I watched some of my previous eye videos, some of which were more than two years apart, and re-examined the progress made. It dawned on me that, for my vision to be completely automated, I'd might need another some such amount of progress as was achieved in between those two videos.

Thus when being completely honest with myself I realize that it might take another two years. I'm hoping one year but I should mentally prepare for the worst. It's clearly possible to streamline my visual system and remove the remaining blockages providing me with a proper functional level but it will take some more time and concentrated effort. Not to get lost or discouraged I work in blocks of six months. When looking at it this way there are only four of those blocks left! That doesn't sound too bad!

I'm already much less in a warlike state of mind than four  years ago. It's interesting how my temper has cooled as my vision has further improved. However, there is still a vital need for improvement. Drawing on the last twenty years of experience I learned that you can't just go running around like some idiot hoping things will resolve themselves. Therefore I organised myself and got the political support I need to pursue my goal. No man can do it alone. Certainly not if there is no official support system whatsoever (clueless ophthalmologists/strabologists screwing over their patients, no social security when binocular vision problems impair productivity, you name it, ...). The current main stream treatment of strabismus by the medical establishment, only offering surgery, is nothing less than continued and organised character assassination of people with binocular vision problems. To survive this you need to approach Vision Rehab as a regular enterprise: deal with the disability and damage inflicted by surgery, find funding and support for your recovery, do the research and ultimately do the work in order to get to the end of the tunnel they have carved out for you. No potential has ever been harnessed without some type of investment. Reliable and workable vision and basic reading ability is one of the fundamental elements of independent life and therefore a must. I'm not planning on depending on others forever. I rather die. It's that simple.

I should never forget to be pragmatic though. In that respect, I'm unrolling some new projects this year. First of which were the Rapid Alternation Goggles as mentioned in my last blog entry. It's going to be a good year! :)

Saturday, January 24, 2015

"Electronic Rapid Alternate Occlusion Goggles" as Anti-Suppression treatment

Following an interesting thread on Facebook and some e-mailing back and forth with Patricia Simone Fink OD and Eric Hussey OD who were generous enough to share their time, research and experience with me, I decided to make another investment in my vision in the form of Electronic Rapid Alternation Occlusion Goggles. New year, new projects and new ways of approaching existing problems!

What are Electronic Rapid Alternate Occlusion Goggles?

"Electronic rapid alternate occlusion (ERAO) using liquid crystal lenses is used to treat suppression of binocular vision, a defect affecting the sensory combination of two eyes’ images into actual binocularity; that is, simultaneous two-eyed, bi-foveal vision. Suppression remains a primary focus of the investigation of visual sensation in strabismus and amblyopia. However, abnormal binocular sensation in the form of suppression also occurs in the absence of strabismus and amblyopia as intermittent central suppression (ICS). As the name implies, intermittent central suppression is a repetitive on-and-off form of loss of central visual sensation. Active therapies for suppression, and ICS in particular, almost always involve two components: a bilateral (bi-optic) visual environment (e.g., a stereoscope) and visual motion."

Demonstration videos

By Eric Hussey OD

Idea and research

Without stealing too much of Eric Hussey's spotlight I want to explain some of the ideas behind the treatment.

In his study 'Remote treatment of intermittent central suppressionimproves quality-of-life measures' Dr Hussey extensively tests this type of goggles on young adult students at Job Corps with significant reading difficulties due to diagnosed intermittent central suppression. These are students without strabismus or severe amblyopia but have lapses of interrupted binocular vision disrupting their reading abilities.

Why does this type of intermittant suppression happen? Traditionally suppression was thought of as a cortical inhibitory process all the way back at the visual cortex. Hussey, however, proposes that suppression is not solely contributable to inhibition at the cortical level. He suggests that suppression is the result of lack of development or disruption of the motion (magnocellular) neural pathway. This lack of development in the early stages of the visual process results in a lack of binocular integration further down the line, notably at the visual and extrastriate areas of the cortex.

"As an alternative to the cortical inhibitory explanation, Iʼve suggested that motion is the “on-switch for seeing” and that ICS (Intermittant Central Suppression) is a deficiency in the motion pathwayʼs ability to keep the image alive. Lack of motion signal lets the visual sensation drop out through the same mechanism as Troxlerʼs Perceptual Fading. That would explain why anti-suppression therapies revolve around visual motion in a bilateral field. Since Troxlerʼs probably happens at or near the Lateral Geniculate Nucleus, viewing that visual drop-out in the context of developing visual neurology in an infant might well explain some of the cortical changes in strabismus and amblyopia. Defect at a neurologically lower area will affect development of neurology in higher areas. This differs from the more top-down conventional wisdom summed up in the word Bielschowsky used to explain strabismic suppression: Diplopiaphobia. ... Merrill Allen theorized that a 9 Hz alternation rate made use of the Bartley Phenomenon brightness enhancement, in this view representing an improved visual signal at the cortex." - From the User Document accompanying the goggles

This principle is further elaborated in Eric Hussey's paper 'Is Anti-Suppression the quest for visibility' which will be published in the journal of Optometry & Visual Performance in the near future.

So if in cases of Intermittant Central Suppression inhibition at the visual cortex is not the main problem but rather an underdeveloped primary visual motion pathway, treatment should be targeted accordingly. Motion should be used stimulating this pathway and consequently encouraging more solid binocular vision.

"This does mean Iʼm suggesting suppression is a primary visual problem that is a result of lack of development of the motion (magnocellular) neural pathway. Developmental, yes, although Iʼve documented whiplash-produced ICS in an adult who did not show a suppression prior to the trauma. I suspect suppression and ICS in particular is not a simple function of stress. Development and/or trauma are involved. Thatʼs why we treat it with therapy and why lenses do not eliminate suppression. Lenses may reduce fatigue, fatigue may make ICS more evident, and therefore lenses may increase reading time before sensory meltdown, but lens application doesnʼt eliminate suppression." - From the User Document accompanying the goggles

In short when using Rapid Alternate Occlusion while doing a binocular activity these goggles provide a constant motion stimulus, even if put on a frequency at which motion is no longer consciously perceived. Frequent use wakes up this underdeveloped motion pathway, increases binocular viewing time and gradually 'glues' the eyes together. To learn about the consequent improvements in reading ability in students undergoing the treatment, which are above those of control groups and not attributable to any other factors, you should take the time to read the 'Remote treatment of intermittent central suppression improves quality-of-life measures' study.

Other ways this device may influence binocular vision (according to me)!

Vision is as much about retinal information (the visual stream) as it is about extra-retinal information (proprioception and efference copy). If you don't understand some of those words, that's alright.

As mentioned above, the goggles stimulate the visual motion perception pathway by the constant motion of the rapid on off alternation and thus a constant change in retinal input. That is the grunt work of anti-suppression, as Eric calls it, and should ultimately 'glue' the eyes together.

Rapid Alternate Occlusion might also influence the interplay of retinal and extra-retinal information. During the brief period of occlusion your brain doesn't have a visual reference of where your eyes are pointing, forcing your visual system to rely on other mechanisms like proprioception to keep its gaze steady and avoid uncontroled retinal slippage. If during occlusion the visual system relies too much on (absent) retinal information to stabilize gaze, and too little on extra-retinal information, one or both of the eyes will start drifting. Uncontroled retinal slippage is what sometimes happens to me while using the goggles because the proprioception and control of the muscles surrounding my eyes (extra-ocular muscles) has been significantly impaired through strabismus surgery.

Therefore, another effect of these goggles then is that they constantly force the visual system to re-evaluate itself and stay busy relying on different neural information to accomplish gaze stability. This too will improve visual stamina! As it forces the visual motion pathway to stay active and develop itself more fully, it also forces these two types of neural input to integrate more fully to deal with the visual challenge imposed by the goggles.

How I currently use it 

I have a visual history of alternating strabismus with pretty good eye sight in both eyes. I have experienced constant double vision for a couple of years. Nowadays my eye alignment has improved to the point that I have aligned eyes most of the time. Traditionally I used to be a esotrope but after surgery my strabismus became non-committant with a tendency towards exotropia. Right now I still have Convergence Insufficiency and intermittant suppression in certain fields of vision resulting in a lack of real binocular fusion.

I'm pretty confident as far as further ocular motility improvements go. I can eliminate the Convergence Insufficiency by continuing my visually conscious lifestyle. It's also important to realize that these are not separate issues. If Convergence Insufficiency disrupts eye alignment for near tasks, there is no fusion. If there is no binocular fusion, eyes have a tendency to wander.

With these goggles I hope to continue and accelerate the 'grunt work' of anti-suppression. It will do so by means of a combination of the retinal and extra-retinal information mechanisms described above.

I use it every day while doing not so spectacular tasks like watching TV, daily domestic activities (if it doesn't get in the way) or maybe some brief reading. I have yet to use it with a Cheiroscope as demonstrated in the video next time I go for VT. It does feel intense and the increased visual load tires you. Unsurprisingly it also tires people without a history of binocular problems. Go figure.

I have been instructed to use it 40 to 50 minutes a day, 5 to 7 days a week. If that is too taxing, I should work up to it. That is what I am doing. I think I'm more or less at 20 minutes a day. I use it in periods of 5 to 10 minutes a time at a setting of 5Hz with equal 'open time' for both eyes as I am not severely amblyopic. As Eric puts it: "The hope would be that we literally improve/wake up the central visual sensation or central visual signal which means your brain should have the information necessary to glue your eyes together. With diligent use, I’d like to think that the end of the year might bring some improvement. Neurology is tough stuff, though."

Nevertheless, the theory makes sense and it feels visually intensive in various ways so I'm very curious about what the results of my experiment will be!

More information about another provider of Rapid Alternate Occlusion treatment and trails

Monday, January 5, 2015

How does it feel to live with Ménière's syndrome?

Earlier I wrote about the intricate link between the visual and the vestibular system. They cannot be understood separately. During this research on the vestibular system I stumbled upon something called Ménière's syndrome.

What is Ménière's Syndrome?

(Taken from the book 'Vision Rehabilitation'.)

"The etiology of Ménière’s syndrome is not completely understood but is considered to be idiopathic (meaning the cause is unknown) endolymphatic hydrops. Symptoms occur when excessive amounts of endolymphatic fluid swell the endolymphatic space in the membranous labyrinth. Onset is typically spontaneous with symptoms of severe rotational vertigo, fluctuations in hearing, tinnitus, and aural fullness.

Intervals between episodes are symptom- free and may be days, weeks, months, or years. Triggers may be stress, fatigue, changes in barometric pressure, some foods, excessive dietary salt, or by other illnesses. When the initial episode of Ménière’s occurs following TBI, it is identified as posttraumatic Ménière’s syndrome.

It is uncommon and symptoms may not be manifested for weeks or months or years after the injury. Hamid reported that a diagnosis of Ménière’s syndrome is “certain” in the presence of
(1) two or more spontaneous episodes with rotational vertigo for 20 minutes or longer,
(2) audiological assessment showing hearing loss (unilateral or bilateral), on at least one occasion,
(3) tinnitus or aural fullness reported in the affected ear,
(4) other etiologies were excluded (i.e., vestibular schwannoma), and
(5) histopathological findings in the temporal bone.

Treatment begins with a trial of medical management with diuretic therapy and a restricted sodium diet (2000 mg/day). During severe episodes of vertigo, diazepam (antianxietal), or meclizine (antihistaminic vestibular suppressant) may help. Abstinence from alcohol, nicotine, and/or caffeine can be beneficial. Studies involving intratympanic injections of gentamicin (an ototoxic antibiotic) are exploring other methods to relieve severe vertigo. However, vertigo may be relieved but some hearing loss could occur. Vestibular rehabilitation can be beneficial for teaching the patient to use movement and balance strategies. Prognosis may be good with early identification and treatment. If aggressive medical management fails, a final resort involves surgery to destroy vestibular nerve tissue or to prevent vestibular signals from going to the brain."

What is it like to have Ménière's?

It just so happens that a little while after reading about Ménière's that I met someone suffering from this syndrome over the internet. She likes her privacy so she won't be mentioned by her real name. Let's call her Hillary for sake of simplicity.

Hillary is 56 years old and lives in Minnesota. Because she suffers from Ménière's, a vestibular disorder, her Vestibulo-Ocular Reflex is impaired. She has nystagmus, balance, posture and gait problems. She has tried to do gaze stabilization through vestibular therapy but it hasn't worked as well as she wished. That is the reason why she is exploring the workings of human vision and visual rehabilitation. Here's an excerpt of a conversation I had with Hillary.

HILLARY: When I was in Vestibular Therapy, I noticed during the gaze stability exercises how much my jaw, neck and shoulder muscles worked harder to keep my head steady. It was contributing to my vertigo. It felt like I was trying to thread a needle on a moving train.

While watching your short videos demonstrating your eye movements, I think I noticed this in you too . The forehead muscles or the jaw muscles moved first, then the eye followed – the other body muscles try to help get the eye on task. 

I think part of the problem is that you are holding the fixation target (the pen) yourself. An OT suggested that I find an old-fashioned desk pen holder so I don't use my other postural muscles to complete an ocular fixation task. The idea is to keep the jaw, neck and shoulder muscles out of the equation 

I try to develop static postural control and keep my head in the same plane in space while moving my eyes independently. Maybe that is similar to focusing on your eyeglass supports as you do in the beginning of the video. It’s more static – you aren't including any micro movements from you jaw, neck or shoulder muscles.

MICHAEL: You are quite the observer! Amazing! The 'thread a needle on a moving train' metaphor is very spot-on too! One of the biggest problems I experience because of the remaining Convergence Insufficiency is the cramping up of my left jaw while reading or trying to read. After a relatively short amount of time I usually have to stop because of jaw pain. Then I have to 'unwind'. The pen holder might be a good idea. How did Vestibular Therapy turn out for you?

HILLARY: Vestibular therapy helped somewhat. I have fluctuating symptoms (Ménière's) so everyday is unpredictable. I'm working on gaze steadiness now. Six years ago, if I were to direct my eyes upward, I would fall down.

MICHAEL: Ha, I read about Ménière's syndrome recently. I'm sorry to hear you had such a hard time. Do you have any idea about what caused Ménière's in your case?

HILARY: Ménière's is idiopathic - which means they don't know the specific cause. I'm sure mine was caused by a series of genetic and environmental triggers. One ear has a slow-draining tube then add to that several ear infections as a child, allergies, a poor functioning immune system, etc. I had several Meniere's episodes - maybe one a year - from age 20 to age 35. Episodes became more frequent after that. I think I was diagnosed around the age of 40. The average age of diagnosis among Ménière's patients seems to be in the 4th decade. There were only a few doctors in my area that had the equipment and experience to diagnose this condition. 

credit to Shayne Town and his Meniere's in Art facebook page

MICHAEL: Wow, I see. That puts a perspective on things... Clearly our situations are different but I identify with the unpredictability even though I don't suffer from Ménière's exactly. Taking naps does somewhat help for me. Do you experience Tinnitus (perception of sound when no external sound is present)?

HILLARY: Tinnitus! Yes, it would drive me batty. I did TMJ exercises and can now modulate it down from a roar to a hum. I think part of controlling the Tinnitus has to do with controlling blood flow pressure.

MICHAEL: Honestly, I don't know what TMJ means but congrats for making such great progress! Gosh, you have been fighting your way through A LOT of sensory attacks!

HILLARY: TMJ stands for temporomandibular joints. Clenching the jaw can reduce blood flow to ear. Hearing damage and some medications can cause it too. I wear my earplugs often in loud places as a prevention measure too.

Before I understood how much eyes and vestibular are connected, I would think of the British women who learned to still hang out the wash in between the World War 2 bombs because "Monday is washing day."

A lot of reducing the anxiety of unpredictability is establishing whatever predictability you can muster. That's one reason I try to "anchor" the object I am trying to see.

MICHAEL: I like the World War 2 anecdote. I often felt like that. Whatever came down, you have to try to keep calm and carry on.

Understanding the problem itself helps a lot though. So there's that. Gradually stabilizing my visual world is helping to take a lot of that uncertainty away. External problems are relatively easy to overcome when you have mastered the internal neurological problems. I'm very glad I posted the videos and got your insights, Hillary. Thanks a lot!

HILLARY: After fifteen years of vestibular and physical therapy, I learned a few things! I enjoy your writing very much and thanks for sharing the video! Now I'm typed out because it takes a lot of effort for me. While some activities are invigorating mentally, they can be very taxing neurologically later on. I'm sure you understand. Talk to you later!