Congratulations to the 2014 BC Optometrist of the Year: Dr. M.K. Randhawa!

In a ceremony earlier today, the British Columbia Association of Optometrists named Dr. M.K. Randhawa, its 2014 Optometrist of the Year!

Visual system plasticity

There has been considerable evidence that the plasticity of the human visual system persists beyond a so-called "critical period" in early childhood.  The most famous example of this is the case of neuroscientist Susan Barry, who achieved 3D vision for the first time in her life at the age of 47 through optometric vision therapy.  Her book about that experience, Fixing My Gaze was Amazon's fourth most popular science book of 2009. What vision therapy did for Susan Barry was an example of how visual rehabilitation is possible well into adulthood because od the plasticity of the visual system.  

As another example, the National Eye Institute funded a study that showed that amblyopia can be treated in young adults, well beyond the critical period of early childhood which was previously thought to be the limit beyond which no change was possible. 

A new study published in the Proceedings of the National Academy of Sciences of the United States of America examined a small number of patients who experienced early-onset (it began before age 1 year), extended-duration ( it lasted 8–17 years) severe visual impairment due to cataracts in both eyes. When the cataracts were removed and the corrective lenses implanted, the patients displayed considerable improvement in contrast sensitivity, which is a measure of vision ability.  The study adds to the body of evidence that improvement in visual function can be achieved well beyond early childhood.   The authors comment on the results as follows:

These results reveal that the visual system can retain considerable plasticity, even after early blindness that extends beyond critical periods.

However, it is still true that the earlier that vision problems are caught and treated, the easier it is and the better are the results.  That's why it is recommended that children have an eye exam at six months of age and then every year thereafter.  We still want to catch vision problems as early as possible. 

Source

Development of Pattern Vision Following Early and Extended Blindness Proc. Natl. Acad. Sci. U.S.A 2014 Feb 04;111(5)2035-2039, A Kalia, LA Lesmes, M Dorr, T Gandhi, G Chatterjee, S Ganesh, PJ Bex, P Sinha

Amblyopia treatment

A large focus of what we do at our Vancouver eye clinic is the treatment of amblyopia using optometric vision therapy.

Developmental optometrists have long used active forms of therapy to rehabilitate the lazy eye that does not see well in amblyopic patients. The advantages of therapy over patching are that therapy is much more enjoyable for children than wearing an eye patch.  Moreover, therapy develops the binocularity (i.e. binocular vision or the two eyes working together as a team) of the visual system.

While optometrists have been doing this for a very long time, only recently have eye surgeons and the wider medical community come on-board with this approach. Dr. Leonard Press has found this passage in a new book on Vision Development by Dr. Daw, Professor Emeritus of Ophthalmology and Neuroscience at Yale University, where Dr. Daw acknowledges that vision therapists have been using effective active forms of therapy for a long time.

“Use of perceptual learning and video games has helped by increasing activity and attention as the therapy is done. Many of the principles have been employed by pediatric vision therapists for some time, but the publicity generated by “Stereo Sue” and others has helped to broadcast them.”

As stated in this passage, much credit goes to Dr. Susan Barry (known as "Stereo Sue") and her book Fixing My Gaze for increasing awareness of vision therapy techniques.  Dr. Barry is a neuroscientist, who was born with strabismus (an eye turn) and had lived all her life without stereo vision, meaning that she could not see in three dimensions. Her case was also the subject of an article in the New Yorker by Oliver Sacks.

She had three surgeries to "correct" the eye turn cosmetically but she still could not see properly and the eye was still turned, although less than before. She had lived this way for over 40 years until she met optometrist Dr. Theresa Ruggiero. Dr. Ruggiero treated Susan with vision therapy which corrected the eye turn and allowed her see in three dimensions for the first time in her life.

Thanks to vision therapy and the work of developmental optometrists, amblyopia is now widely regarded as a binocular problem, not a monocular problem upon which the old treatment of eye patching was based.  Here is one quotation from a study that makes the point:

amblyopia is an intrinsically binocular problem and not the monocular problem on which current patching treatment is predicated. Thought of in this way, the binocular problem involving suppression should be tackled at the very outset if one is to achieve a good binocular outcome as opposed to hoping binocular vision will be regained simply as a consequence of acuity recovery in the amblyopic eye, which is the current approach and which is often not found to be the case.

Hess, Robert F.; Mansouri, Behzad; Thompson, Benjamin, A Binocular Approach to Treating Amblyopia: Antisuppression Therapy. Optometry & Vision Science:September 2010 - Volume 87 - Issue 9 - pp 697-704

Related Articles

Risk Factors for Amblyopia in Preschoolers
Dec 12, 2013

Evidence that patching alone is not enough for amblyopia treatment
Apr 29, 2013

Patching alone is not good enough for amblyopia ... - See for Life
Apr 22, 2013

More evidence that patching alone is not enough for amblyopia treatment ...
Apr 29, 2013

The ultimate amblyopia infographic - See for Life
Jun 01, 2013

Advance treatment for amblyopia (lazy eye) - it's not patching
Friday, September 20, 2013

Active therapy is more effective for amblyopia
Nov 20, 2011

Take your kids to see "Thor": doctor's orders!
Thursday, October 25, 2012

Video Game therapy, optometric vision therapy are more effective than patching alone in treating amblyopia
Sunday, November 20, 2011

Is your child at risk for a vision disorder? Take this interactive quiz to find out. Wednesday, February 8, 2012

Vancouver Parents: Amblyopia treatment in a nutshell!
Monday, July 1, 2013

Vision therapy for vergence and accommodation

A new case report was published in the latest issue of the Journal Optometry & Visual Performance, which supports the effectiveness of in-office vision therapy for the treatment of vergence and accommodation dysfunctions.

Vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision.

Accommodation  is the process by which the eye changes its focusing power to maintain a clear focus on an object as its distance from the eye varies.

The case report discussed a patient who was 10-years and 10 months old and underwent 16 visits for vision-based therapy along with home reinforcement (vision therapy homework). The authors used several methods to measure accomodation and vergence before and after therapy, including the Convergence Insufficiency Symptom Survey (CISS), near point of convergence (NPC), positive fusional vergence range at near (PFV), accommodative amplitude, and accommodative facility. The measures taken showed decreased symptom severity following therapy.

The in-office vision therapy program used in the study was identical to that used in the well known Convergence Insufficiency Treatment Trial studies and produced measurable changes in vergence and accommodation in the case subject, who also had convergence insufficiency.

The results not only demonstrate the efficacy of vision therapy but also provide an illustration of the plasticity of the oculomotor system, which is not fully developed at 10 years of age and responds well to interventions like vision therapy.

Source

Optometry & Visual Performance
Objective Assessment of Vergence and Accommodation After Vision Therapy for Convergence Insufficiency in a Child: A Case Report Optometry and visual performance 2014 Feb 04;2(1)7-12, M Scheiman, KJ Ciuffreda, P Thiagarajan, B Tannen, DP Ludlam

Cosmetic contact lenses sold on the internet attract bacteria

A new study published in the journal, Contact Lens Anterior Eye looked into whether surface pigments on cosmetic contact lenses lead to increased adherence of bacteria.

The researchers bought 15 brands of cosmetic contact lenses over the Internet. To determine whether the lenses had surface pigments, the researchers did a standard rub-off test to confirm whether the pigments were on the surface or embedded.  Most of the brands failed (13 out of 15) the rub-off test meaning that the pigments were on the surface and these brands showed significantly higher bacterial adherence.

The conclusion is that purchasers of cosmetic contact lenses risk bacterial infections unless they make healthy choices for their contact lens wear.  Consult your eye doctor before buying contact lenses over the Internet.

Source

Contact Lens & Anterior Eye: The Journal of the British Contact Lens Association
Microbial Adherence to Cosmetic Contact Lenses Cont Lens Anterior Eye 2014 Jan 16;[EPub Ahead of Print], KY Chan, P Cho, M Boost

Stereo vision (depth perception) in preschool children - what if my child can't see 3D?

One of the easiest ways to diagnose a vision disorder in a very young child is to test his or her stereo acuity or depth perception.  Poor 3D vision is often caused by a vision disorder, some of which may be serious disorders that are best treated in early childhood.  Poor 3D vision may even be the sing of life threatening diseases such as tumours, as in this famous story from Ontario.

A new study published in the journal Optometry & Vision Science examined the a large population of pre-school children and tested their depth perception using the Stereo Smile II test.  The researchers then looked at the association of poor 3D vision with vision disorders.

The study found that children with vision disorders had significantly worse median stereoacuity than that of children without vision disorders. Children with the most severe vision disorders had worse stereoacuity than that of children with milder disorders.

The researchers also found that testability was excellent at all ages of the children included in the study. The results support the validity of the Stereo Smile II for assessing random-dot stereoacuity in preschool children.  The results also point to the need to take children who have poor stereo vision to a developmental optometrist to be evaluated and treated for developmental vision disorders that may be the cause of the poor stereo vision.

For more information visit our 3D vision web page at http://www.visiontherapy.ca/3dmediaandvision.html

Stereo vision, vision therapy and the TED talks

Stereo vision and treatment of depth perception problems with optometric vision therapy has been the subject of TED talk featuring neuroscientist Dr. Susan Barry:

Related articles on children and depth perception

What is 3D Vision Syndrome? 

Don't like 3D movies? You may have 3D Vision Syndrome

Take your kids to see "Thor": doctor's orders!

Life threatening disease found in girls eye - lack of 3D vision was the clue

Fixing My Gaze - Can you imagine not having 3D vision?

TED - ideas worth spreading - Susan Barry on how vision therapy gave her 3D vision

Source

Stereoacuity and Vision Disorders in Preschool Children
Optom Vis Sci 2014 Jan 23;[EPub Ahead of Print], EB Ciner, G-S Ying, MT Kulp, MG Maguire, GE Quinn, E Graham, D Orel-Bixler, LA Cyert, B Moore, J Huang