Measuring the Eye - Axial Length

The thing with health science is it keeps evolving! So let me explain what axial length measurement is, why this is useful, and who should be having their eyes measured this way.

As you may know already, we are concerned about the myopia epidemic. An increasing number of people world wide are becoming short-sighted, at a younger age.

Why is myopia a concern? Short-sighted eyes are often longer than an average eyeball, and this is associated with increased risk of eye disease in life.

Fortunately we now have a number of treatment methods which clinical studies have shown to slow down the progress of myopia in children. (Including Miyosmart spectacle lenses, soft contact lenses, and ortho-K contact lenses.)

How does the Eye Axial Length Measurement fit in? If we can identify eyes which are longer than expected, armed with this information we can try to harness as many strategies as possible, and monitor these eyes closely.

Conversely it will be reassuring to know if an eye is average length.

How is Axial Length (AXL) measured? There are a number of methods, but the easiest uses an biometer. This is a painless and non invasive - no eye drops.

A measurement scan using optical low coherence reflectometry (OLCR) biometry measures the axial dimensions of the human eye. From the cornea (at the front) to the retina (at the back). These instruments are readily available in a Ophthalmologist’s (eye specialist) clinic for measurements before cataract surgery.

Who should have their eyes measured? We recommend young people who are myopic, especially those identified as at risk of rapid progression. These are children with highly myopic parents, children who present needing a high prescription at the start and children who are at primary school when they need their first pair of glasses.

How often should eyes be measured? As this is a new clinical procedure we plan to measure once and review. We may recommend a second annual measurement for eyes which appear to be of normal length, if the prescription progresses.

For eyes identified as longer AXL we will likely recommend a review sooner.

Where do I go? Book to see Dr Mark Donaldson, ophthalmologist, at Rodney Surgical Centre, Morrison Drive, Warkworth. Phone 09-425 1190. Request an appointment for Myopia Eye Measurement.

What is the charge? The appointment fee is $75.00

Related Articles: New spectacle lens for Myopia Control - Myoismart

Myopia Control

International Myopia Congress Tokyo

In September I was fortunate enough to attend the International Myopia Congress, held in Tokyo (just ahead of the Rugby World Cup). Myopia, or short-sightedness, means vision close range is clear but things further away (TV, the board at school, road signs) are blurred.

As global rates of myopia increase rapidly, particularly in South East Asian countries, there are concerns about the long term impact this will have on future eye disease (risk of retinal detachment, macular degeneration and glaucoma increase with myopia).

The four day congress brought together researchers, academics and clinicians from all around the world and sessions were presented by authors of clinical and scientific research.

The community is trying is understand what causes myopia. This effort included studies into genetics as well as animal research. Other projects look at epidemiology, trying to figure out who is effected and identify environmental factors which may play a role. So far we know the importance of two hours per day time spent outdoors will delay the onset of myopia in children.

One day was dedicated to studies following intervention strategies, such as ortho-K contact lenses, and soft contact lens designs.

Rising rates of myopia have been described as an epidemic, and resulted in some large scale public health initiatives in Taiwan and Singapore. It was inspiring to hear from individuals who had played vital roles in pushing these program’s ahead.

800 delegates attended in Tokyo. The next congress will be in Rotterdam in 2021.

MiSight® Daily Contact Lenses for Myopia Control

We now have MiSight® Daily Contact Lenses as another option for myopia control. This year at the British Contact Lens Association
(BCLA) meeting some promising results were announced from a three-year study for MiSight®. The results indicate MiSight® dual-
focus contact lenses which have alternating visual correction and treatment zones - are effective in slowing myopia progression in
children by 59%. CooperVision, MiSight® manufacturer, reported data from its Clinical  Contact Lens Study showing these lenses
slowed myopia and eye elongation. 

The prevalence of myopia is projected to increase from approximately two billion people worldwide in 2010 to an alarming five billion
people in 2050, bringing with it both short  and long-term health challenges. “Myopia’s growth has been dizzying and now affects the
vast majority of young adults in some countries, especially in East Asia,” said Arthur Back, from CooperVision. “Not only does it create
blurred vision, but also increases the likelihood of serious and blinding eye conditions later in life.
“Early intervention by parents, in partnership with optometrists, is essential for the short and long-term health and well being of their
children.”

The prospective, multi centre, double masked, randomised study enrolled 144 myopic children aged 8-12 years from Singapore,
Canada, England and Portugal. MiSight® was well accepted by the children who continued their daily activities such as school work,
reading, playing outside and computer use while wearing the lenses.  
Parents of participants gave a very positive response, noting that before the study, many were concerned about their children wearing
contacts.  After their children had worn MiSight® 1 day contact lenses for three years, almost 9 out of 10 parents rated their children
‘extremely happy’ with the overall experience. Children could mostly manage their lens wear independently.

Book Online

International Myopia Conference Updates - Spend Time Outside

Updates are filtering through from the International Myopia Conference, Aston University, Birmingham, UK. Some of the studies are confirming our gut instincts - more outside time is beneficial to preventing myopia (short-sight), as well as slowing myopia progression.

In Taiwan, 20% of 7 year olds are myopic, increasing to 85% by age 18. Pei-Chang Wu presented the results of a school based intervention trialled across Taiwan called the ROC (recess outside classroom). ROC involved spending breaks outside (an extra 40+ min / day), educating parents about the risks of myopia and importance of outside time, along with outdoor diaries and sticker reward systems to encourage outdoor time and breaks from near work at home. A total of nearly 700 Grade 1 children across 16 schools participated. There were two groups, one was a control.

The results? Over a year, this intervention inhibited myopia progression by about 30%. 

This is important as previous data has indicated that outdoor time may only be beneficial to non myopic children, and not once myopia has onset. The ROC program showed a benefit for all children, both myopes and in the incidence of onset of new myopes - 8% in the ROC group compared to 18% in the control group.

The conclusion? This outdoor time stuff really works; for the at-risk pre-myope and the myope. Early interventions matter, provided they result in a change in behaviour.

We look forward to more information coming out of this meeting. If you have any questions regarding myopia please don't hesitate to contact us.

Orthokeratology Society of Oceania

Recently Claire joined the Orthokeratology Society of Oceania (OSO). This group is recognised and trusted as the leading authority on OrthoK in this part of the world. OSO aims to expand the safe use of OrthoK and help reduce the impact of the global myopic epidemic.

Membership of OSO requires completing a training 'BootCamp' and demonstrating skills and understanding of fitting these specialist contact lenses.

We are excited about the possibilities that OrthoK offers. These contact lenses, worn at night, give great vision and freedom from contact lenses and glasses throughout the day. They are also proving very successful in slowing the progression of myopia.  This is a heartening message especially for myopic parents who know from personal experience how eyesight changes throught childhood and adolescence.

Read more about Myopia and OrthoK. Please contact us if you have any questions.

Claire McDonald pictured with OSO Board Optometrists Jagrut Lalu (left) and Alex Petty (right).

Myopia Control

Myopia, or shortsightedness, means distance objects appear blurred and out of focus. In everyday language we use ‘myopic’ to describe a person with a short range focus. Myopia is a growing problem throughout the world. Uncorrected myopia is the second most common cause of blindness globally. Estimates show 22.9% of the world suffers from myopia. Of particular concern are the group with very high prescriptions, or high myopia.

Myopia is not just the need for glasses and high myopia is not simply thicker lenses. With myopia comes increased risk of eye conditions like glaucoma, retinal detachment and macular degeneration. These risks increase with higher prescriptions. 

It is understood there is a genetic component to myopia. Having one parent who is myopic doubles the risk of becoming short sighted. Two parents increase the risk by 8 times. Environmental factors also seem to influence the development of myopia. These include time spent indoors versus outdoors. More time outdoors seems to result in less myopia. Spending a lot of time on close range work, reading and screens, is also associated with more myopia.  

If a child is myopic, the likelihood is this will progress as they grow; while some children have slow rates of progression, for others vision changes rapidly. 

How to control myopia in children has become a hot topic for optometrists. Fortunately there are effective ways to intervene and slow myopia progression. These include Ortho-Keratology (hard contact lenses), multifocal contact lenses, atropine eye drops and progressive or bifocal glasses. Talk to us about the best options for you or your children.

For more information see our resource page, or contact us directly.