Saturday, August 17, 2013

Eye injuries from party foam, silly string and artificial snow

Image: www.jakegarn.com
Eye injuries are the most common cause of blindness in kids.  And the most common cause of eye injuries is sports.  But a new study published in the June 2013 issue of the journal Cornea puts the spotlight on chemical eye injuries resulting from contact with "silly string," "party foam," or fake snow.

The study looked all patients who came to two particular hospitals with eye injuries over a two year period.  Around 100 patients had come with injuries related to party foam.

All patients suffered from chemical conjunctivitis (100%).  Chemical conjunctivitis is also kown as chemical pink eye or "toxic pinkeye".  It can also be caused by getting smoke, liquids, fumes, or chemicals in the eye. Chemical conjunctivitis can look like this:

Image: Wikipedia


79% of patients had superficial punctate keratopathy, which involves the death of small groups of cells on the surface of the cornea (the clear layer in front of the iris and pupil). Symptoms of superficial punctate keratopathy include the following redness, watering, and sensitive to light and decreased vision.

The study authors observed that 85 patients were seen in 2007 compared wit only 11 in 2008. The authors claim that the reduction was directly attributable to increased public awareness because of media coverage (newspapers, radio, and national TV) on the dangers posed by silly string.

Chemical eye injuries of the kind caused by silly string are usually easily treated in the optometrist's office.

We hope that this blog post will increase awareness and therefore contribute towards the prevention of this eye injury.

Source:

Cornea
Party Foam-Induced Eye Injuries and the Power of Media InterventionCornea 2013 Jun 01;32(6)826-829, A Abulafia, F Segev, E Platner, B Simon

Silly string image: Jake Garn, www.jakegarn.com, used with permision.

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Wednesday, August 14, 2013

Myopia control in children and spectacle lens design - how the right lenses can keep your eyes from getting worse

We have written extensively on the very big problem of mypoia and myopia progression.  Not only is it problematic that a child's vision gets more and more blurry as myopia progresses, it also puts the child at higher risk of developing glaucoma and retinal detachments, both of which can cause permanent vision loss.

So far, the best treatment for slowing and even stopping myopia progression is orthokeratology.  A number of studies have shown that orthokertology is effective:


Orthokeratology slows or stops the progression of myopia in children July 6, 2013

Study suggests that young children may benefit from orthokeratology February 14, 2013

New study confirms orthokeratology for slowing myopia progression January 30, 2013

Orthokeratology is shown to be safe for correcting myopia in chidlren Aug 11, 2012

Orthokeratology is shown to be effective in correcting astigmatism and myopia Jun 18, 2012
New study supports orthokeratology for myopia control and for astigmatism correction Jan 10, 2012 

As children's eye doctors we are very interested in treatments that can slow or stop the progression of myopia.

A new study published in July 2013 in the journal Investigative Ophthalmology & Visual Science suggests that the right spectacle lens design can slow the progression of myopia.   The study was titled "Peripheral Defocus and Myopia Progression in Myopic Children Randomly Assigned to Wear Single Vision and Progressive Addition Lenses".

The researchers looked at eighty-four myopic children between the age of 6 and 11 years with myopia that was measured between -0.75 and -4.50 diopters.  They were randomly assigned to wear single vision lenses or progressive addition lenses (often called "progressives" or "no-line bifocals").  The researchers then took measurements to investigate the association between peripheral defocus and the one-year change in central myopia.

The study concluded that the progressive lenses caused a myopic shift in peripheral defocus. Superior myopic defocus was associated with less central myopia progression. This suggests that lens designs like progressives that result in peripheral myopic defocus can potentially be used to slow myopia progression. 

However, orthokeratology is still the most effective way to slow myopia progression and is the only treatment that has been shown to stop myopia progression.

Citation:

Invest. Ophthalmol. Vis. Sci. 2013 Jul 09;[EPub Ahead of Print], DA Berntsen, CD Barr, DO Mutti, K Zadni

Source:
Investigative Ophthalmology & Visual Science
Peripheral Defocus and Myopia Progression in Myopic Children Randomly Assigned to Wear Single Vision and Progressive Addition LensesInvest. Ophthalmol. Vis. Sci. 2013 Jul 09;[EPub Ahead of Print], DA Berntsen, CD Barr, DO Mutti, K Zadnik


Tuesday, July 30, 2013

Visual information is more important than vestibular input in causing motion sickness

Here is more on motion sickness and see-sick syndrome. An Australian study conducted in 1996 concluded that visual information is more important than vestibular input in causing motion sickness. Here is the abstract:

Aviat Space Environ Med. 1996 Oct;67(10):955-62.
Visual and vestibular components of motion sickness.
Eyeson-Annan M, Peterken C, Brown B, Atchison D.
Source
Centre for Eye Research, School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia.
Abstract
BACKGROUND:
The relative importance of visual and vestibular information in the etiology of motion sickness (MS) is not well understood, but these factors can be manipulated by inducing Coriolis and pseudo-Coriolis effects in experimental subjects.
HYPOTHESIS:
We hypothesized that visual and vestibular information are equivalent in producing MS. The experiments reported here aim, in part, to examine the relative influence of Coriolis and pseudo-Coriolis effects in inducing MS.
METHODS:
We induced MS symptoms by combinations of whole body rotation and tilt, and environment rotation and tilt, in 22 volunteer subjects. Subjects participated in all of the experiments with at least 2 d between each experiment to dissipate after-effects. We recorded MS signs and symptoms when only visual stimulation was applied, when only vestibular stimulation was applied, and when both visual and vestibular stimulation were applied under specific conditions of whole body and environmental tilt.
RESULTS:
Visual stimuli produced more symptoms of MS than vestibular stimuli when only visual or vestibular stimuli were used (ANOVA F = 7.94, df = 1, 21 p = 0.01), but there was no significant difference in MS production when combined visual and vestibular stimulation were used to produce the Coriolis effect or pseudo-Coriolis effect (ANOVA: F = 0.40, df = 1, 21 p = 0.53). This was further confirmed by examination of the order in which the symptoms occurred and the lack of a correlation between previous experience and visually induced MS.
CONCLUSIONS:
Visual information is more important than vestibular input in causing MS when these stimuli are presented in isolation. In conditions where both visual and vestibular information are present, cross-coupling appears to occur between the pseudo-Coriolis effect and the Coriolis effect, as these two conditions are not significantly different in producing MS symptoms.
Related Articles

See sick syndrome - diziness, light sinsitivity, motion sickness, vestibular problems
Monday, July 29, 2013

Motion sickness and vision therapy
Apr 18, 2012

Vertigo is often a symptom of eye disorders- dizzy patients may benefit more form a developmental vision examination than an MRI
Apr 20, 2013

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Monday, July 29, 2013

See sick syndrome - diziness, light sensitivity, motion sickness, vestibular problems

Image courtesy of winnod / FreeDigitalPhotos.net
Many patients come to us with motion-sickness type symptoms.  Dizziness and sensitivity to light are common symptoms.  Many of these patients have been to many other specialists, such as the family physician, neurologists, vestibular specialists, ear, nose and throat specialists and even acupuncturists.

Typically, all of these professionals tell the patient that there is nothing wrong.  That may be true as far as their particular specialty is concerned.  This is not surprising, as studies have shown that vertigo is an underestimated symptom of eye and vision disorders. Many professionals that a patient consults are simply not equipped with the knowledge or experience to diagnose an eye or vision problem that can cause vertigo-like symptoms.

However, something is definitely wrong.  Many of these patients can no longer drive safely and cannot even go to the supermarket without feeling nauseous.

One recent case found us after she went to her optometrist after consulting various doctors for over a year. The optometrists found that the patient's eyes were misaligned, a condition that commonly causes the dizziness and vertigo-like symptoms she was experiencing.  The patient was referred to our Vancouver eye clinic for treatment.

Patients like this often suffer from "see sickness syndrome", also known a neuro-ocular vestibular dysfunction - it has also been referred to as supermarket syndrome because trips to the supermarket often trigger nausea in these patients.

Dynamic adaptive vision therapy is an effective treatment.  Vision therapy relies on the principle of neuroplacticity and involves a doctor and therapist treating the patient with exercises to "re-wire" the eye-brain connection, teaching the patient new eye and motion related skills.  In this way, vision therapy is similar to speech therapy or occupational therapy but focused, of course, on the eyes and visual system.

See Sick Syndrome (SSS) is the combination of motion sickness and photophobia. SSS is not well understood by many professions and is not typically diagnosed during a standard eye or medical examination. However, many patients will recognize themselves when presented with a list of symptoms.

Based on clinical observations by Dr. Gillilan (an American optometric physician and a leading doctor in this field), SSS occurs in approximately 6% of the female population and 1% of the males, and it is usually familial.  Dr. Gillian's website is at http://www.seesicksyndrome.com/.

Symptoms of see sick syndrome

The severity and frequency of various SSS symptoms can vary widely. Most SSS patients have at least two of the following:

  • motion sickness (e.g., nausea, headache, dizziness, fatigue, malaise, drowsiness, depression, bodily warmth, pallor, and/or cold sweats) 
  • repeated eye movement, especially when observing rapid motion
  • unusual sensitivity to light. 

The symptoms of SSS and the ability to manage motion can vary from day to day. One reason is that motion effects can be cumulative. An exposure to motion can make one less able to handle a new exposure for up to three days later.

SSS symptoms are usually mild in children but become more severe over a period of years. This is may be caused by an avoidance of  symptom producing activities by adults and the resulting loss of adaptation and coping strategies.

Almost all SSS patients have life-long histories of carsickness, which occurs almost exclusively in the daytime. The reason for this is that you see less peripheral motion when driving at night. Reduced awareness of objects in the periphery (functional tunnel vision) also occurs in SSS but patients usually don't notice this although the often report a history of clumsiness, which is consistent with having reduced peripheral awareness.

The following conditions can make SSS worse:

  • fatigue, 
  • pre-menstrual syndrome (PMS), 
  • hypoglycemia 
  • inner ear conditions 
Here is a chart of symptoms organized according to severity and symptom category that proves more detail and outlines the breadth of the SSS cases that we encounter.
 Mild
 Moderate
 Severe
 Car Sickness
·   Mild car sickness.
·   Cannot read (look down) in a car more than a few seconds without nausea, headache and/or dizziness.
·  Necessity to be the driver to avoid nausea while traveling in a car, even on a straight road.
·   Inability to look backwards in a car without nausea. 
·  Nausea when driving on tree lined roads when the sun casts shadows across the road.
·   Riding in or even driving a car for more than a few minutes may result in severe HA, fatigue, and/or nausea.
 Light sensitivity
·   Unusual sensitivity to light to a moderate degree. 
·  Must wear sunglasses outdoors, even on cloudy days. 
· Feels uncomfortable in brightly lit buildings or places with shiny floors such as grocery stores, classrooms, offices, or malls.
·   Eye pain or headache when exposed to a “flash of light” or being outside without sunglasses, even on cloudy days, or being in a brightly lit place.
·     Unusually long after images after looking at most sources of light (several minutes). 
·  Computer screen brightness causes discomfort. 
·  Sensation of being “blinded” when looking at oncoming headlights.
·   Severe sensitivity to light both indoors and out.
·   They are the type of person to turn off lights and pull down shades.
·  severe dislike of light
 Visual
·  Inability to sit close to a movie screen or watch movement of a train or a carnival ride without nausea, headache, and/ or dizziness.

·  Inability to look at stripes or watch rapid movement on television without nausea,headache, or dizziness.
· Inability to watch more than minimal motion without dizziness or nausea, such as watching ones own hand while eating.
 Headache
· Frequent and sometimes daily “dull” or “pressure” headaches.
·  Exposure to any activities which involve observations of movement or eye movement for more than a few minutes can cause severe headaches which may last a few days.
·   Constant or very frequent nausea, headaches, or dizziness which can range from mild to severe.
Dr. Gillian has a YouTube channel under the name MotionDoctor1,where you can watch some informative videos.  Here are some of them:




Related articles

Vertigo is often a symptom of eye disorders - dizzy patients may benfit more from a developmental vision examination than an MRI... - See for Life
Apr 20, 2013

Motion sickness and vision therapy - See for Life
Apr 18, 2012

Sunday, July 28, 2013

Autism and vision - looking askance, poor eye contact, side viewing


We work with autistic patients, mostly children, at our Vancouver eye clinic. As parents and autism care providers know, vision based behaviors are characteristic of autism. Here are a few examples:

  • Poor eye contact, 
  • staring at lights or spinning objects, 
  • looking askance, 
  • side viewing, 
  • general difficulties giving attention to visual stimuli, 
  • Squints or closes an eye, 
  • Stares at certain objects or patterns, 
  • Looks through hands, 
  • Flaps hands, flicks objects in front of eyes, 
  • Looks at objects sideways or with quick glances, 
  • Shows sensitivity to light (photophobia), 
  • Becomes confused at changes in flooring or on stairways, 
  • Pushes or rubs eyes, 
  • Has difficulty making eye contact, 
  • Widens eyes or squints when asked to look, 
  • Bumps into objects, 
  • Is fascinated by lights and shadows, and 
  • Touches walls or tables while moving through space. 

People often assume that most autism spectrum behaviors are caused by the disorder. But they could be caused by underlying and treatable vision problems. Read more.

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