A New Year’s Snellen Resolution

We’ve long struggled to effectively communicate the distinction between “sight” and “vision”.  Oh, I don’t mean we’re not effective in creating this distinction. We know how basic this is, and tools such as the great George Page video makes the distinction so obvious.  Obvious to us, that is.  But the public still seems to have a difficult time grasping this.  The past decade of laser surgery to “correct vision” has only served to confound the issue, as marketing wrapped the idea of “perfect vision” as related to seeing 20/20 or better.

So at what point do we decide to accept that the public isn’t getting the message the way we’re sending it?  Those Snellen Charts with the International “NO” symbol around them aren’t deterring the public from conflating sight with vision.  Here’s a typical example from the website Health Central:

To determine how clearly a person can actually see, the Snellen eye chart is used, with rows of letters decreasing in size:

• From a specified distance, usually 20 feet, a person reads the letters using one eye at a time.
• If a person can read down to the small letters on the line marked 20 feet, then vision is 20/20 (normal vision).
• If a person can read only down through the line marked 40 feet, vision is 20/40; that is, from 20 feet the patient can read what someone with normal vision can read from 40 feet.
• If the large letters on the line marked 200 feet cannot be read with the better eye, even with glasses, the patient is considered legally blind.

Heck, even the www (widely worshiped wikipedia) conflates visual acuity, spatial resolution, and “20/20 vision”.  So what do you say?  Is it time, on this first day of January 2012 to drop the charade?  I’m going to make an argument that it is.

Fernette and Brock Eide, two physicians outside of the vision care field who have a greater grasp of what we do in developmental/behavioral optometry than most of their colleagues, put together a great PowerPoint on The Different Ways of Seeing.  Therein lies the best argument for shedding the distinction between eyesight and vision.  There is no verb for vision, at least not in the eye or vision care field.  If you Google Visioning you’ll come up with uses of the verb, but related to strategic thinking and planning.  When we think of vision operating as a verb in the ophthalmic and vision care fields, we’re stuck with some aspect of seeing.

No other sensorimotor modality has this verbiage problem.  In the auditory domain the public seems to have accepted that hearing sharply doesn’t equate to the full range and cognition of the auditory system.  The idea of central auditory processing deficits as distinct from auditory acuity is now widely recognized.  I suspect that is in part owing to ENTs keeping their noses, or at least their ears out of the domain of expertise of audiologists and speech-language pathologists.  This makes it simpler for educators and the public to receive a coherent message.  We have no such unanimity in the “eyecare” field.  So for this year, at least, let’s drop the tired and ineffective distinction between “vision” and “sight”, and go down the auditory path.  There’s hearing, and there’s central auditory processing.  In fact, the auditory field has dropped the central and they simply refer to it now as auditory processing, or the brain part, as distinct from hearing, or the ear part.  Ear is structure, auditory processing is function.

In parallel fashion, there is sight and there is visual processing.  Simple.  Screw the Snellen Chart and 20/20-isms and vision.  It’s as irrelevant as decibels.  Do you hear what I hear?

Transplanted Corneas Are A Window To The Soul

You may remember the movie At First Sight, starring Val Kilmer and Mira Sorvino, based on the true story of Virgil, penned by Oliver Sacks.

The Sacks story on Virgil’s bilateral corneal transplants, To See and Not to See, was also published as a clinical vignette in his book, An Anthropologist on Mars.  Here is an excerpt.  It’s a striking and poignant reminder of how vision is a learned process, and the dynamic and inseparable interplay of eyes, brain, and visual pathways.  Virgil’s story was a forerunner of Mike May’s experiences, which I wrote about in the Journal of Behavioral Optometry.

Let’s transition from Oliver Sacks to Mind Hacks, the superb blog from authors Tom Stafford and Vaughan Ball.  Their post today bears the title above.  It lends a fascinating note on the social meaning of eyes and why people are much more reluctant to donate the cornea after death than other bodily organs, citing a recent article from the journal Transplantation.  Here is an excerpt that speaks volumes:

“Medicine and science have long understood the body as a “machine.” This view has fitted with medical notions of transplantation, with donors being a source of biologic “goods.” However, even a cursory glance at the rituals surrounding death makes it apparent that there is more to a dead body than simply its biologic parts; in death, bodies continue as the physical substrate of relationships. Of all the organs, it is the eyes that are identified as the site of sentience, and there is a long tradition of visual primacy and visual symbolism in virtually all aspects of culture.

It therefore seems likely that of all the body parts, it is the eyes that are most central to social relationships. A request to donate the eyes therefore is unlikely to be heard simply in medical terms as a request to donate a “superfluous” body part for the benefit of another. That the eyes are not simply biologic provides one explanation for both the lower rates of corneal donation, compared with that of other organs, and the lack of adequate corneal donation to meet demand.”

- Leonard J. Press, O.D., FCOVD, FAAO

 

 

 

 

http://visionhelp.wordpress.com/2011/06/02/mind-hacks-and-medical-foibles/

 

 

The Wastepaper Basket Test

In the course of searching for something else I came across a wonderful site this morning, a compilation of neuro-ophthalmology nuggets.  The site belongs to the gentleman pictured on your left, Lars Frisen, an MD, PhD at the University of Gothenberg in Sweden.  Dr. Frisen has quite a sense of humor, pictured here with his neuro-ophthalmology mentor, Dr. William Hoyt from UCSF with a fountain of knowledge between them, as he notes.  Dr. Frisen is a member of the Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, at the University of Gotehnberg (which I still remember from my lecturing gig in Sweden many moons ago is pronounced “You-ti-ber-ya”).

Ah, yes – the wastepaper basket test.  It’s not what you’re thinking, and has nothing to do with value judgments, though if you do the test chairside you’ll be sure to raise a few eyebrows.  It’s one of a number of tests that Dr. Frisen details for unmasking hidden ocular torsions with a 3D twist.  Peruse the whole website – there are many hidden gems here!

- Leonard J. Press, O.D., FCOVD, FAAO

The Divided Brain

In a prior post, The Paradoxical Brain, we mentioned that in acquired brain injury, or ABI, patients typically experience damage to the right hemisphere which results on hemispatial neglect or inattention in the left visual field.  The left hemisphere, which directs the right visual field, is typically involved in sustained, broad, open attention characterized by vigilance and alertness.  The right hemisphere, which directs the left visual field, is characterized more by narrow, sharply focused attention to detail.  Consider this in the context of the psychiatrist Iain McGilchrist’s presentation on the divided brain.

Another psychiatrist who has explored visual implications of the divided brain is Frederick Schiffer.  His theories may have you looking at the emotional implications of hemispheric differences massaged through binasal occlusion.  Here are the goggles that he describes using:

- Leonard J. Press, O.D., FCOVD, FAAO

Seminar on VT at NJIT Biomedical Engineering

I mentioned the other day that I’d follow up on the seminar I gave Friday morning to the New Jersey Institute of Technology’s Department of Biomedical Engineering.  It was a joy to do the presentation, and I learned much about the institution and their work that I hadn’t previously been aware of.  Though the Department of Biomedical Engineering is only in its eleventh year, it already boasts the largest number of Master’s Degree candidates in the country, currently at 140.  They have 45 current Ph.D. candidates, which isn’t too shabby either!  The point person who invited me was Tara Alvaraez, Ph.D. who along with her grad students has developed a specially adapted system, VisualEyes, for objectively studying the effects of optometric vision therapy.

Some brief lineage here.  Dr. Alvarez did her post-doc work with Dr. John Semmlow at Rutgers Biomedical Engineering.  Dr. Semmlow is a close colleague of Dr. Ken Ciuffreda at SUNY Optometry, stemming from their mutual mentor, Dr. Lawrence Stark who, as you can see from this video, was a fascinating individual.

Dr. Ciuffreda has collaborated frequently with Dr. Semmlow, and Dr. Alvarez joined in several of their projects and publications.  Dr. Ciuffreda works closely with Diana Ludlam, COVT, in the field of neurorehabilitative optometry, and it was they who initiated an invitation to Dr. Alvarez to speak at the NORA conference in 2008.  It was there that she met Dr. Vince Vicci and began a collaboration that continues to bear significant fruit.

My seminar looked at the common linkage between convergence insufficiency, visual attention, and Traumatic Brain Injury (TBI).  I used the construct of Post-Trauma Vision Syndrome (PTVS) introduced by Dr. Bill Padula through which to study these associations.  I reviewed the concepts of visual attention, probing why individuals with convergence insufficiency have difficulty with attaining and sustaining visual attention in near space.  We differentiated between sustained attention, alternating attention, and divided attention.  We then looked at likely anatomical substrates for PTVS through some human and animal models, and centered on midbrain structures such as superior colliculus as a site where shearing forces and coup/contrecoup effects can derail both attention and convergence in one’s peripersonal space.  We finished with an interactive demonstration of some procedures used optometric vision therapy beyond raw vergence, including the concepts of divided attention, ambient/focal integration, and central-peripheral balance.

The graduate students were delightful to interact with, and after the seminar I had the chance to visit with Dr. Alvarez in her lab and gain more insight into her prior, current and projected work.

- Leonard J. Press, O.D., FCOVD, FAAO

Mindsight, Neural Integration and Goldie Hawn

Sounds like the straight line for one of Carnac the Magnificent’s brain teasers, doesn’t it?  Except this is no joke.  I’ve just posted some background on Goldie’s new book about mindfulness on my personal blog here:

http://pressvision.wordpress.com/2011/10/04/goldie-hawns-10-mindful-minutes/

… and you can learn more about the background of Goldie Hawn’s work through her Foundation here:

http://www.thehawnfoundation.org.

Reflections, Relationships, and Resilience are the Three R’s that are every bit as crucial in a child’s learning and development as the traditional “Three R’s” of Reading, Writing, and Arithmetic.

That should be sufficient background to launch you into the TED-MED talk that Goldie presented in San Diego along with Daniel J. Siegel, M.D., who wrote the foreword to her new book.  It’s a powerful message that resonates with anyone engaged in a learning and/or therapeutic environment with children.

- Leonard J. Press, O.D., FCOVD, FAAO

New Evidence-Based Support for Amblyopia Therapy

Dennis Levi, O.D., Ph.D. is Dean of the College of Optometry at U.C. Berkeley.  It’s also safe to say that he’s the leading researcher in the world on amblyopia therapy. I wrote an essay for the Journal of Behavioral Optometry that chronicled how I re-connected with Dennis at a Vision Sciences Society meeting, and how this ultimately led to Sue Barry and I joining Dr. Levi at a meeting during which we saw the seeds for this reserach being planted.

Ironically, in the same issue of the JBO, Dr. Jeffrey Cooper published a paper that included a review of his computerized program, Amblyopia iNet, as a support to amblyopia therapy.  So clearly we’ve known for some time clinically that an interactive video game-like format can enhance the results of amblyopia therapy.  And, as our colleague Dr. Dan Fortenbacher pointed out last year, eye patching alone is no longer the standard of are in optometric vision therapy.

Dr. Ed Melman, a skilled and well-read primary care optometric physician and colleague in New Jersey, called our attention this morning to an article from Levi’s Laboratory that he was excited to share.  It’s from the August 2011 issue of  PLOS Biology, and is entitled Video-Game Play Induces Plasticity in the Visual System of Adults With Amblyopia.  The release from U.C. Berkeley interviewing Dr. Levi and fellow researcher Roger Li can be found here.  The significance of this work is not only that active therapy achieves results beyond what passive occlusion accomplishes, but adds to the impressive body of literature regarding residual plasticity in the adult visual system.  This is welcome news for adults with amblyopia who are receptive to improving their visual function.

- Leonard J. Press, O.D., FCOVD, FAAO

 

Practical Wisdom – Part 5: The Neural Architecture of Pattern Recognition

In part 4 I indicated that we’d carry on with a look at some of the neural architecture of pattern recognition.  Schwartz & Sharpe introduce this part of the basic architecture and operation of cognitive networks.  At the heart of neural networks is the concept of a flow of information proceeding from input units to output units, mediated by hidden units in between, and trained by backpropagation – a fancy term for feedback.  Here is a beautiful website that gives you all the basics of neural networks, and you’ll immediately be struck by the parallels between the modeling and how we approach vision therapy.

At the most basic level, the output unit might be function such as cyclopean vision.  The visual system receives input from the two eyes, performs a series of operation within the hidden units binocular function, and generates a unified output indicative of these operations or functions.  As we said earlier, the flow of information isn’t strictly forward, from the eyes through the rest of the brain and the body.  There is massive parallel processing going on in numerous areas simultaneously and the feedback of information, or backpropagation in learning, is every bit as crucial as the flow of information forward.

A model of this as applied to a crystalline lens system would postulate an input signal, processing of the signal through intermediate operations, an output of the lens in the form of a response, and feedback to the beginning of the loop.  The key, as far as we’re concerned, is modulation of the input signal.  This can occur externally from the visual environment as an external signal, or internally from within the visual system.

A few more global points from Schwartz & Sharpe:

1) Cognitive network theories hypothesize that the process of going from a naive child to an experienced, pattern-recognizing adult is a process by which the vast set of connections is tuned by this kind of experience.

2) Most of the tuning is done by changing the pattern and strength of connections in the intermediate units.  This is where the pattern that is to be recognized resides.

3) It is the tuned network that provides rapid pattern recognition, allowing the elements of the network to operate in parallel.

4) Each unit essentially influences, and is influenced by many others.

5) Elements are redundant throughout the network, allowing for some ambiguity so that the system doesn’t get thrown out of whack when conditions aren’t perfect.

- Leonard J. Press, O.D., FCOVD, FAAO

Emotional Vision

What’s love got to do with it?  Tina Turner doesn’t necessarily have the eyes in mind when she belts out that tune, but neuroscientists do.  Trolling for something else this morning, I came across a a great viewpoint piece I had forgotten about, with the provocative title of EMOTIONAL VISION – Nature Neuroscience 2004 It’s written by Ralph Adolphs, a social scientist who hangs his hat at Cal Tech in Pasadena and his coat at the University of Iowa’s Department of Neurology.

The gist of the article is that emotions can directly influence sensory processing, and can do so at surprisingly early stages.  Surprising, that is, only if one is not  familiar with the concepts of behavioral and developmental optometry.  In this diagram, the components of the  amygdala, the major brain structure involved in emotions, can be seen to modulate key visual regions of the brain that follows a ventral stream of information which helps us in recognition objects and form.

A dramatic example of emotions affecting visual processing is the Streff Syndrome, in which patients exhibits constriction of their visual field and reduced visual acuity unrelated to structural damage of the eyes.  Other manifestations of visual stress include the  cognitive imbalances seen in patients with acquired brain injury and strabismus.

It is still not known precisely how visual information from the retina reaches the amygdala, but as neuroscience learns more about about these connections we will have an even better model for understanding the power of optometric vision therapy that complements, but goes well beyond the kinematics of eye movement or the optical power of the eye’s structures.  Our good colleague Dr.  Bob Sanet is fond of quoting Dr. Lawrence Macdonald as saying: Eyes don’t tell brains what to see; brains tell eyes what to look for, and the amygdala connection provides further evidence of this.

Another intriguing concept cited in this article is that abnormal activation of the fusiform gyrus and amygdala observed in people with autism when viewing faces may result from impairments in the same mechanism.  Ralph Adolphs speculates that dsyfunctional modulation of visual cortices early in life might contribute to the development of abnormal social perception in persons with autism.  This theory is consistent with an article I co-authored with my mentor and colleague, Dr. Jack Richman, on Optometry’s role in the early detection of Autism Specturm Disorders, in a theme issue on Autism for the journal Optometry and Vision Development.

- Leonard J. Press, O.D., FCOVD, FAAO

 

Sacks Appeal – The Mind’s Eye – Part 5

I hadn’t planned to write anything further about The Mind’s Eye, but the book review of it in today’s LA Times moves me to add a few more words.  Most of the reviews of Oliver Sacks’ latest book mention the story of “Stereo Sue” only in passing, and typically that Sue’s story serves as a contrast in the joy of stereopsis gained, whereas Oliver’s revelation is the pain of  stereopsis lost.  Meehan Crist goes beyond the obvious in her observations about the significance of  what it is like to experience perceptual alterations of the kind that Sue has discovered and that Oliver has endured.  Have a look at it here.  A few other sources for fans of the book are the review in today’s NY Times; the B&N online interview; 20 questions at Kansas City.com; and a video interview of Oliver about his life’s work by NY1.  Regrettably I haven’t been able to take advantage of being in proximity to Oliver’s recent talks about his work and this monumental book, but these pieces add to the delight of how well he expounds not only on the sense of sight, but on his personal vision and that of others.

- Leonard J. Press, O.D., FCOVD, FAAO