South Asians are at higher risk of glaucoma - January is Glaucoma Awareness Month

Look out South Asians living in North America! You have a higher risk of glaucoma than other ethnicities, according to a new American study that looked at glaucoma risk among Asian Americans, including those of Indian and Pakistani ancestry. While the study looked at Americans, the findings will likely apply to Canadians who share a similar diet and lifestyle.

The study concluded that, among Asian Americans, Japanese Americans have the highest risk (9.5%) followed by Indian and Pakistani Americans (7.7%) of open angle glaucoma, the most common variant of the disease.


If you have a high risk of glaucoma, the best thing that you can do to protect yourself is to see the eye doctor at least once a year. Glaucoma can only be detected early enough in an optometric eye examination. It does not cause pain or blurriness or other obvious symptoms. That is why doctors often call glaucoma the "silent thief of sight". The disease is so gradual that you will likely not know that you have suffered permanent vision loss, beginning with your peripheral vision. Some people with undiagnosed glaucoma are no longer legal to drive and don't know it. Read this older post for more about glaucoma.

For optometrists and ophthalmologists, this study means that they need to carefully examine their Asian patients and check both the pressure inside he eye and assess the condition of the optic nerve as well as perform visual field testing where appropriate.

Vision therapy or surgery for strabismus (esotropia, exotropia)?

Strabismus surgery.  Image: wikipedia.

We here at Vision Source Vancouver think that it makes good sense to use effective non-surgical vision therapy to treat strabismus (sometimes called cross eyes, eye turn, esotropia, exotropia).  The reason is that strabismus or eye muscle surgery has many risks of bad or harmful outcomes.   

This website has featured articles outlining the risks associated with strabismus surgery and reported on studies that demonstrate the effectiveness of vision therapy in treating most kinds of strabismus -without any of the risks associated with surgery.

Professor Dominick Maino, a fellow of the College of Optometrists in Vision Development, recently had a discussion with an eye surgeon on his own blog, MainosMemos, on why surgery, because of the risks and results that are not satisfactory for many patients,  should only be used as a last resort. As only one example of undesirable outcomes, a study on surgery 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. 

Other risks of strabismus surgery include death, infections, blindness, scars, mistakes like surgery on the wrong eye, etc.  You can read more about risks here. 

Repeat strabismus surgeries in children are causing concern because of new research that links anesthesia use in kids to learning disabilities and attention deficit hyperactivity disorder later in life.   In fact, the eye surgeon who commented on Professor Maino's blog had these same concerns, writing:

One can't ignore the studies regarding anesthesia and the potential for future cognitive impairment. This is a work in progress and the pediatric specialties are following closely.

However, the surgeon goes on to say:

Like anything in medicine (and you should be well-versed since you received an "Excellence in Medicine" award) you have to consider the risk-vs.-benefit ratio. If I have a young patient with a 40 PD decompensated exotropia who is in danger of developing irreversible amblyopia and loss of stereoacuity, 30-40 minutes of anesthesia for strabismus surgery is not going to prevent him or her from getting into Harvard. [NB vision therapy and patching will not touch a 40 XT]. People need to be properly educated, look at all of the facts, and not over-react.

If there are no studies that prove that anaesthesia during strabismus surgery is totally safe, our point is that it is not sensible to take the risk when you don't need to.  The basic ethical principle in medicine is "do no harm".  If there is a treatment option that has no risk of harm, it should be the first choice.  There are some types of strabismus that vision therapy cannot effectively treat, and for those surgery is probably a good idea given the cost-benefit analysis.  But for the most common kinds of strabismus, vision therapy is a safe and effective treatment. 

Dr. Maino referred to the following recent studies on strabismus surgery that highlight the reasons why it should not be first choice option for treating strabismus:

Haridas A, Sundaram V. Adjustable versus non-adjustable sutures for strabismus. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004240. DOI: 10.1002/14651858.CD004240.pub2

"No reliable conclusions could be reached regarding which technique (adjustable or non-adjustable sutures) produces a more accurate long-term ocular alignment following strabismus surgery or in which specific situations one technique is of greater benefit than the other. High quality RCTs are needed to obtain clinically valid results and to clarify these issues. ......"

Rowe FJ, Noonan CP. Botulinum toxin for the treatment of strabismus. Cochrane Database of Systematic Reviews 2012, Issue 2. Art. No.: CD006499. DOI: 10.1002/14651858.CD006499.pub

The majority of published literature on the use of botulinum toxin in the treatment of strabismus consists of retrospective studies, cohort studies or case reviews. Although these provide useful descriptive information, clarification is required as to the effective use of botulinum toxin as an independent treatment modality. Four RCTs on the therapeutic use of botulinum toxin in strabismus have shown varying responses ranging from a lack of evidence for prophylactic effect of botulinum toxin in acute sixth nerve palsy, to poor response in patients with horizontal strabismus without binocular vision, to no difference in response in patients that required retreatment for acquired esotropia or infantile esotropia. It was not possible to establish dose effect information.Complication rates for use of Botox™ or Dysport™ ranged from 24% to 55.54%.

Elliott S, Shafiq A. Interventions for infantile esotropia. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004917. DOI: 10.1002/14651858.CD004917.pub2

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

Br J Ophthalmol. 2012 Oct;96(10):1291-5. Epub 2012 Aug 11.Surgical intervention in childhood intermittent exotropia: current practice and clinical outcomes from an observational cohort study. Buck D, Powell CJ, Sloper JJ, Taylor R, Tiffin P, Clarke MP; Improving Outcomes in Intermittent Exotropia (IOXT) Study group. 

After surgery 65% had fair to poor outcomes and 20% of the subjects remained XT or the XT recurred

BMC Ophthalmol. 2012 Jan 18;12:1. doi: 10.1186/1471-2415-12-1.The improving outcomes in intermittent exotropia study: outcomes at 2 years after diagnosis in an observational cohort.
Buck D, Powell CJ, Rahi J, Cumberland P, Tiffin P, Taylor R, Sloper J, Davis H, Dawson E, Clarke MP.

....8% ...of those treated surgically required second procedures for overcorrection within 6 months of the initial procedure and at 6-month follow-up 21% ... were overcorrected ....

January 2013 is Glaucoma Awareness Month

January is Glaucoma Awareness Month. We urge everyone to take control of their eye health and have an eye exam to help minimize the risk of developing glaucoma.  When you lose vision to glaucoma, you never get it back.

Glaucoma is the second leading cause of blindness in Canada. Even so, public awareness around glaucoma is low. For example, according to a recent survey by the American Optometric Association:

• 90% of respondents think glaucoma is preventable. Only
10% know it's not, but that it's treatable.
• 86% don't know what part of vision glaucoma affects.
• 72% think glaucoma has early warning signs.

The truth is that the only defence against glaucoma is early diagnosis and treatment. People who wait until something noticeable happens to their vision are too late. They have already suffered permanent vision loss.

Regular eye exams are the first line of defense for early detection of glaucoma. Glaucoma is often called the silent thief of sight because it often strikes without pain or other symptoms. That's why it is critical for patients to receive a dilated eye exam from their eye doctor so that eye pressure and and the nerves in the eye can be examined for signs of glaucoma.

Ethnicity affects your risk of developing glaucoma. For example, South Asians have a higher risk than Europeans of developing glaucoma.

Recent studies show that Canadians are not taking basic steps (getting eye exams) to protect themseves against glaucoma. And by the time they are diagnosed, they have already lost vision that they will never get back. It does not have to be that way if you take control of your health and get regular eye exams.

Related Articles
The best protection against glaucoma
Feb 27, 2012

Vision loss from glaucoma - preventable if caught early
Nov 02, 2011

South Asians are at higher risk of glaucoma
Apr 28, 2011
Health warning on eye drop - glaucoma risks
Jan 05, 2012
The myopia epidemic: why it is so dangerous- myopia and glaucoma risks
Oct 12, 2011

Only 38 years old and risking blindness - man suffers permanent vision loss after avoiding the eye doctor for years 
May 24, 2011

Children's eye exams

Did you know that a child should have their first eye exam at the age of six months and then annually thereafter?  Like most medical conditions, eye health and vision problems are much more treatable when caught early.

Good vision in infants is also critical for visual, brain and overall development.  A child with poor vision is prevented from effectively exploring and understanding the world and deprived of valuable brain stimulation.  Studies have also proven what eye doctors already know, that vision problems that persist lead to adult problems such as joblessness, incarceration, lower income and behaviour problems.  Life threatening diseases can also lurk in the eyes of young child.  Read more...

 

Here is a video of Dr. M. K. Randhawa talking about a patient story from our Vancouver eye clinic involving a five-year-old girl who had been legally blind her whole life - until she came in for an eye exam:

Image courtesy of arztsamui / FreeDigitalPhotos.net

Can nutrition fight glare, increase contrast, help you see farther, and help you process visual information faster?

This is Viso XC lens coating that fights glare.
Can the right eye nutrition do this?

Much attention has been devoted lately to macular pigment (MP), which is composed of the  carotenoids lutein and zeaxanthin.  Macular pigment is found in a part of your eye called the retina.  In fact, it is found in high concentrations in a part of the retina called the macula.   People who have lots of lutein and zeaxanthin in their system have a much lower risk of developing eye diseases like cataracts and macular degeneration.  Those diseases can cause permanent vision loss and blindness.

The interesting thing is that, in addition to protecting you from very bad eye diseases, recent science has discovered that lutein and zeaxanthin have the following every-day vision benefits...Read more...