Vision therapy for saccades improves reading

Dr. Dominick Maino has an excellent post on the blog of the College of Optometrists in Vision Development about a new study published in the journal Clinical Pediatrics by a group of researchers including one from the Illinois College of Optometry that shows that vision training (vision therapy) for saccadic eye movements improves reading in children. Read more

When changing or replacing contact lenses part way through the day does not improve discomfort - a new study explains why

An interesting study was published in the October 2013 issue of Optometry & Vision Science.  It addresses a situation well known to many contact lens-wearers. Over the course of a day of contact lens wear, discomfort increases for some people.  And for some of these people, changing or replacing the lens to a fresh lens part way through the day does not help. Why is that?  This study may have an answer and suggests that it is not the lens, it's physical changes happening on the surface of your eyes.

The study examined the comfort reported by patients throughout and at the end of a 10-hour day of wear. Subjects were surveyed on a 0–100 scale for comfort on two separate days.

On the first day, nothing was done to the lenses they wore throughout the day, and study participants reported decreasing comfort during the day. This result was expected, as many optometrists observe this in the clinic. Doctors have long argued about the cause of this discomfort. Was it due to ill-fitting lenses?  Or was it due to changes in the surface of the eye caused by contact lens wear?

To answer that question, on the second day the lenses were removed after 5 hours of wear. After removal, either the same lens was reinserted, or it was replaced and a new lens. The assumption was that if lens comfort improved by removing and replacing the same lens, then the surface of the eye was to blame.  On the other hand, if comfort improved after switching to a new lens, then the fit of the lens may be at fault.  The control group wore lenses continuously for 10 ours with no reinsertion or switching to a new lens.

The results showed that there was no difference between the control group (that wore the lenses continuously for 10 hours) and either the group that removed and reinserted the same lens or the group that switched to a new lens.  This lead the researchers to conclude that the increasing discomfort throughout the day was not related to the lenss. They suggested that the likely cause of increasing discomfort was a "fatigue-like response in one or more ocular tissues or stimulation of ocular surface nociceptors induced by the presence of the contact lens."

Source

Consequence of Wear Interruption for Discomfort With Contact Lenses
Optom Vis Sci 2013 Oct 17;[EPub Ahead of Print], EB Papas, D Tilia, D Tomlinson, J Williams, E Chan, J Chan, B Golebiowski



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Long-Term Orthokeratology Patient Satisfaction

Yet another study supporting the use of orthokeratology (also known as corneal reshaping) appeared in the November 2013 issue of the scientific journal Contact Lens.  The new study found that long-term satisfaction rates with orthokeratology treatment were high.  We have provided orthokeratology at our Vancouver eye clinic since we opened.

Orthokeratology is a safe and effective vision correction method where patient wears a lens retainer at night that reshapes the cornea of the eye.  The result is clear vision the next day without the need to wear corrective lenses during waking hours.  A number of studies have also shown that orthokeratology is effective in slowing or stopping myopia progression and that is save and effective in children.

The researchers who conducted the new study used a questionnaire where patients rated their visual experience and satisfaction levels with orthokeratology on a scale of 0-10.

The results of the study showed that light distortion in low light conditions decreases over time and decreases more quickly in younger patients and in patients with lower amounts of myopia. Predictably, visual performance declined after a patient skipped a night of lens retainer wear but this was usually tolerated.  In addition, the majority of patients report that they skipped overnight wear at least 1 night per week, but tolerate the resulting transient decrease in vision. Overall satisfaction was high, even after skipping a night of lens wear.

Here are the results in the study's own words:

More than 50% of patients skipped lens wear at least 1 night per week. The most common wearing pattern was 6-8 hours a day for 72.7% with 54.5% of patients wearing lenses every 2-3 nights only. Subjective vision scores after lens removal was 9.1 ± 1.1 after having worn the lenses and 8.1 ± 1.4 after skipping lens wear for 1 night. Subjective vision scores before lens insertion at the end of the day was 6.9 ± 2.0 and 5.8 ± 2.4, respectively. The number of hours until noticeable blur reduced with increased level of baseline myopia (r = 0.396; P < 0.001). 

Source:

Eye & Contact Lens
Subjective Satisfaction in Long-Term Orthokeratology Patients Eye Contact Lens 2013 Nov 01;39(6)388-393, E Santolaria, A Cerviño, A Queirós, R Brautaset, JM González-Méijome

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Depressed? Anxious? Maybe your eyes are too dry. Dry eye syndrome linked to depression and anxiety.

A study published in the journal Current Eye Research examined anxiety and depression in patients with dry eye syndrome.  The authors of the study concluded that “anxiety and depression are correlated with Dry Eye Disease, demonstrating that [it] is an important public health
problem that merits increased attention and research.”


Vision Source Vancouver optometrists see the effects of dry eye syndrome on patients every day.  Sometimes it is an irritating thing in the background.  However, dry eye syndrome can get so bad that it can wreck your life by taking away the things you love to do and ruin your relationships with your loved ones.


Dry eyes may seem trivial but for chronic sufferers of dry eye syndrome, their dry eyes significantly decrease their quality of life.  Many of these people are not able to drive, work on the computer for very long or even watch TV with family because their eyes will not tolerate the activity for more than a few minutes. Dealing with the discomfort, burning, scratching, and pain of dry eye syndrome can make your life bad enough that you may become clinically depressed.


People who are older and who have had dry eye syndrome for longer are most at risk of depression and anxiety.  This suggests that the earlier you seek treatment the better it is for your mental health. 


For dry eye sufferers, the best advice is to go see your eye doctor as soon as possible because a wide variety of effective treatments are available for dry eye syndrome and one of them can probably improve your dry eye symptoms.  For most dry eye sufferers, it is possible to avoid the spiral of discomfort, pain, burning and eventual depression and anxiety that can come from dry eye syndrome. 


For some more information about dry eye syndrome read these posts:

• Caffeine improves dry eye syndrome
• Women make dry eye worse with makeup
• The basic facts about dry eye syndrome
• Dry eye can come from computer use (because you blink less)

Caffeine improves dry eye syndrome - according to new study from Tokyo researchers

Caffeine intake can significantly increase the eye's ability to produce tears, a finding that could improve treatment of dry eye syndrome.  This is according to a new study published in the journal Ophthalmology by researchers at the University of Tokyo's School of Medicine.

Dry eye syndrome affects millions of people.  Depending on the study you read, between 5% and 30% of the population will experience dry eye syndrome at some point in their lives.  The severity of dry eye syndrome ranges from an annoyance to a debilitating, vision threatening illness that can ruin lives by making it impossible for the sufferer to hold down a job or drive a car.  Women and people who have had LASIK surgery are more at risk of dry eye syndrome although it can affect anyone.

All of the 78 participants in the study produced significantly more tears after consuming caffeine than after taking a placebo.

Dry eye syndrome has a number of different causes that include slower than normal of tear production, tear quality that is worse than normal or tears evaporating faster than normal from the surface of the eye.  Dry eye syndrome is sometimes called tear dysfunction syndrome to focus attention on the chief culprit of the disease: some sort of problem with tears. 

Caffeine is known to increase the secretions of various glads in the body.  For example, caffeine increases the secretion of saliva and digestive juices.  The study suggests that it may stimulate the gland the produces tears.

Dry eye can negatively impact the quality of your life.  If you think you have it, go see your optometrist.  A number of different treatments are available and it is likely that one of them can help you.

Here is a recent post we did on dry eye syndrome:

• Women make dry eye worse with makeup

In a city like Vancouver BC, where our clinic is located, there is a Starbucks on every corner.  I wonder if optometrists write fewer per capita prescriptions for dry eye medication.  If public health researchers do a study on that, you will here about it here first! 

The image at the top of this post is the chemical structure of caffeine.

Study proves that half the eyewear sold online is junk. Why read the study when you can enjoy this cool infographic?

It is becomming more well known that a recent research study from Pacific University has proven  that half the eyeglasses sold online are junk.  This blog wrote about the study just yesterday. 

Today, the BC Doctors of Optometry have come out with this infographic on the topic.  The information is in line with what we actually see in our Vancouver optometry clinic with patients comming in with headches, blurry vision and glasses that just don't work, fit or suit the patient's needs. 

Studies show that half the glasses sold online are junk. What kind of problems might I experience?

A research study from Pacific University has proven what most eye doctors have already been told by their patients, that half the eyeglasses sold online are junk and can cause lots of problems. 

But how might substandard eyeglasses affect you and what problems might you experience if you were the unfortunate owner of a pair of substandard eyeglasses? 

Dr. M.K. Randhawa, of Vision Source Vancouver optometrists, talks about this problem in this video:



Here is a link to the study from Pacific University:   http://optometrists.bc.ca/upload/documents/Speak_Out/Safety_and_compliance_of_prescription_spectacles_ordered_by_the_public_via_the_Internet.pdf

Incidentally, studies have also found that half of ready-made reading glasses are junk. 

Another risk of strabismus surgery? Increased risk of learning disabilities and attention deficit hyperactivity disorder (ADHD) because of exposure to anesthesia.

Strabismus - a condition where the eye abnormally turns in or out due to one or more of the eye muscles malfunctioning - is often treated with surgery in which the properly functioning muscle is cut and re-attached so that it balances with the malfunctioning muscle, hopefully making the eyes look straight. 

Strabismus surgery has well many well-known risks and complications.  However, there is a growing body of research that is causing even more worry for strabismus surgery patients because these patients are often very young and must frequently endure repeat surgeries, which means repeat exposure to anesthesia and therin lies the risk.  

Recent research suggests that the risk of developing learning disabilities and attention-deficit/hyperactivity disorder (ADHD)increases after early exposure to surgeries requiring general anesthesia - surgeries like strabismus surgery.

Repeat strabismus surgeries are common

Eye surgeons often lament the need for repeat eye surgeries for strabismus patients. Surgeon, John W. Simon,  notes that "patients must regularly contend with the unfortunate reality that even the most  accurately planned and carefully executed surgery may not totally eliminate the deviation [i.e. the misalignment of the eyes] or completely normalize rotations.  In addition, strabismus tends to recur over time."  This limitation of sugery often results in the the patient being subjected to repeated surgeries - all of which may be unsuccessful.  It is not uncommon for a patient to have had two or three or more surgeries and still have a noticeable misalignment or poor binocular vision together with depth perception problems or all  three. For this reason, the surgeon's view is that  "strabismus is less a problem to be cured than a problem to be controlled, with the minimum number of surgeries": Simon, John W. Complications of Strabismus Surgery. Current Opinion in Ophthalmology. 2010. 21: 361-366.

One study found that only 45% of children had successful alignment of the eyes at an eight-year follow up to their strabismus surgery.  And while the low percentage was disappointing enough, 20% of the children had to undergo repeat strabismus surgeries which were ultimately unsuccessful: Awadein A, Sharma M, Bazemore MG, et al.Adjustable suture strabismus surgery in infants and children. J AAPOS 2008; 12:585–590.

Recent studies link repeat exposure to anesthesia at an early age to learning disabilities and ADHD

The latest study to link repeated anesthesia exposure to learning/behavioral disorders was  published by researchers at the Mayo Clinic in February, 2012 in Mayo Clinic Proceedings.  It linked repeat surgeries requiring anesthesia to a doubling of the risk of developing ADHD.  The study's authors concluded that "children repeatedly exposed to procedures requiring general anesthesia before age 2 years are at increased risk for the later development of ADHD even after adjusting for comorbidities."

The February 2012 study follows up on earlier studies that linked repeat surgeries requiring anesthesia to an increased risk of developing learning disabilities.  The authors of an October 2011 study on anesthesia and learning disabilities published in the journal Pediatrics stated the alarming conclusion that "[r]epeated exposure to anesthesia and surgery before the age of 2 was a significant independent risk factor for the later development of [learning disabilities] but not the need for educational interventions related to emotion/behavior. We cannot exclude the possibility that multiple exposures to anesthesia/surgery at an early age may adversely affect human neurodevelopment with lasting consequence."

Similar results were published in a 2009 study published in the journal Anesthesiology which looked at children under the age of 4 who were exposed to anesthesia.  The researchers concluded that “exposure to anesthesia was a significant risk factor for the later development of learning disabilities in children receiving multiple, but not single anesthetics. These data cannot reveal whether anesthesia itself may contribute to learning disabilities or whether the need for anesthesia is a marker for other unidentified factors that contribute to learning disabilities."

The three studies referenced above were undertaken after studies in animals showed that repeat exposure to anesthesia at a young age caused damage and degeneration in the brain that manifested in the animals as learning and behavioral problems.  The research conducted so far in humans indicates that the worrisome findings from the animal studies apply to humans as well.

UPDATE: new study shows that even a single exposure to anesthesia during surgery is associated with developmental problems in children. [updated January 18, 2013]

There is now new evidence that even a single exposure to anesthesia can be dangerous for a child.  A study published in December 2012 in the journal Evidence Based Medicine  found that children exposed to anaesthesia for surgery under 3 years of age were found to be at significantly increased risk for developing disabilities in receptive language, expressive language, total language and abstract reasoning at age 10.

The study authors commented that:

This study was the first to report the effects of anaesthetic exposure early in life on neuropsychological outcome using individually administered neurocognitive tests. Perhaps due to the greater sensitivity of these tests, Ing and colleagues observed disability even following a single exposure in early childhood, while several previous reports, utilising group-administered tests, had only detected learning abnormalities following multiple exposures.

Is general anesthetic used for young patients undergoing strabismus surgery?

While topical and local anesthesia are used for some strabismus surgeries in certain patient demographics, it appears that general anesthetic is commonly used for children younger than the mid-teens. Click here to read more about anesthesia use in strabismus surgery. According to Cyber-Sight, a program of ORBIS International, a non-profit organization that prevents and treats blindness by providing quality eye care, "most immature patients (younger than midteens) require general anesthesia for extraocular muscle surgery."

Because doing strabismus surgery early in life is generally considered important to its success, surgery in children younger than age 2 is not unusual. Surgery for strabismus is done as early as 3 months of age in serious cases, particularly if the strabismus is detected early.

Non-surgical alternatives

Given the potential for very bad outcomes following repeat surgeries and the high risk of repeat surgery for strabismus, it is prudent to employ non-surgical treatments where they are available.  Vision therapy is an effective non-surgical treatment for most kinds of strabismus. The success rate of vision therapy treatment of strabismus is in the range of 75%-87%.

Unfortunately, some forms of strabismus do not respond well to vision therapy and surgery may be required.  If surgery is necessary to treat a young patient, surgical approaches that do not rely on general anesthesia, if they are available, should be considered. 

Unanswered questions

While the studies referenced above looked at very young children, at what age does the risk of of learning and behavioral disorders diminish and at what age does it disappear?  Does the risk ever disappear?  We don't know the answer yet but we know that the brain continues to develop until the age of about 25. What is the risk of damage during the full 25 years of brain development?

Ask your doctor the right questions

Patients contemplating strabismus surgery should have a frank discussion with their doctor and raise the issue of repeat surgeries and the risk of learning disabilities and ADHD that comes with repeat exposure to anesthesia.

Also note that strabismus surgery has other complications and risks in addition to the risk posed by repeat exposure to anesthesia.

Research shows that half the eyeglasses bought online are junk

Researchers from Pacific University published a  study in 2011 that tested glasses purchased on-line for compliance of optical and safety requirements. Of the 154 pairs of glasses purchased from the top ten U.S. online spectacle vendors, almost half of them failed at least one parameter of testing.

Staff at my clinic have reported many people comming in with glasses bought online that have numerous problems. 


Some are funny, like the kids who walk in with glasses that are way to big for them.  Their parents want them adjusted so that they fit properly but that is not possible since the frames so big should never be sold to a child.  It is often no consolation that in 5 or 6 years the child may grow into the giant frames. 


Others have headaches from lenses that do not align properly with their eyes.  Some people have progressives that are unusable because no one explained to them the best lens choice for their vision and lifestyle.  The list goes on.