Bay Eye Care Actively Slows Myopia
Myopia (short-sightedness) is increasing around the world, with many now calling it an epidemic. Aside from the burden of needing spectacles or contact lenses to function normally, people with myopia have a much higher risk of blinding eye disease later in life.
Bay Eye Care offers a range of treatment options to slow the progression of myopia, protecting your child's eye health in the future.
How common is myopia?
It is thought that ~30% of New Zealanders are short-sighted, similar to Australian levels. The concern is that this percentage is increasing globally. At its current rate by 2050 five billion people will be short-sighted: half of the world's population. High myopia, the severe form of the condition when your prescription is worse than -5.00D, makes up 20% of this proportion.
What makes my child more likely to become myopic?
There are a number of risk-factors for developing short-sightedness:
Genetics: Having both parents that are also short-sighted increases your child's risk of myopia by 6x.
Ethnicity: There may be an increased rate of myopia in children with an east-asian genetic background.
Prolonged periods of reading and close-work is an increased risk for myopia.
Lack of time spent outdoors is a risk for myopia.
Certain problems with eye co-ordination and focusing increase the risk of myopia.
Myopia comes about due to the eye getting longer. Most patients who develop myopia at a young age (under 20 years) tend to have more aggressive myopia progression and will continue to become more and more short-sighted over time until their eye stops growing. Adults that develop myopia can also progress over time however, especially if they do a lot of reading or computer work in their jobs or studies.
People with myopia will be highly dependent on high-powered glasses or contact lenses for any visual tasks. They often have to keep changing their glasses each year as their eye becomes more short-sighted.
More concerning is that all levels of myopia increase the chance of blinding conditions such as retinal detachment, cataracts, glaucoma and myopia retinal degeneration later in life. This risk of these conditions is much higher as the degree of myopia increases. These conditions are far from rare: myopia maculopathy, a worsening condition causing death of the retinal cells, is the fourth most common cause of visual problems in the UK, ahead of diabetic eye disease.
What does this all mean?
Out of context the implication of myopia can be hard to grasp. It can help to compare myopia with heart disease: Studies show us that the risk factor for eye disease due to any degree of myopia is comparable with the risk of cardiovascular disease (stroke, heart attack etc.) associated with untreated high blood pressure. We all know high blood pressure is a real problem that needs controlling; short-sightedness is no different.
An important concept to remember is that while the risks of eye disease later in life are present for any degree of myopia, the higher the amount of myopia - the higher the risk.
If we can stop the progression of myopia to these high levels then a significant amount of blindness in our community can be prevented. Studies suggest that even a modest reduction in the rate of myopia of 33 % could produce a 73 % reduction in high myopia (above 5.00 D).
What can be done?
Prescribing standard spectacle lenses or contact lenses for your child will do nothing to slow the progression of short-sightedness. As a result, they will require frequent changes to their glasses and will be put at risk of sight-threatening problems in the future. Unfortunately, the lengthening of the eye which causes myopia cannot be reversed, making it critical to control myopia sooner rather than later.
The good news is that there is convincing evidence that certain treatments can slow and even halt the progression of myopia. Bay Eye Care will recommend the most appropriate myopia methods for each person depending on a range of factors.
Our Optometrist's Myopia Story
The personal case of our optometrist, Mr Alex Petty, highlights why myopia control is so important. Alex developed myopia before the age of ten. This progressed throughout his teenage years, eventually stabilising at a high -7.50D in each eye. As a result, Alex suffered two retinal detachments in his left eye in 2009 and another in 2014 in his right eye. Fortunately, through timely surgery these were able to be repaired saving his central vision. If Alex had access to myopia control strategies when he was a teenager, it is unlikely his prescription would have worsened as quickly and these ocular emergencies might have been prevented.
At Bay Eye Care we take a proactive approach to managing myopia. We use instruments to monitor the length of our patient's eyes and have access to all the current myopia control treatments used around the world. During a consultation with our optometrist we will discuss which management option is best for your child's scenario. On average the main treatment options offered at Bay Eye Care should provide, on average, at least 50% slowing of your child’s myopia, which will make a significant difference in lowering their risk of other ocular disease later in life.
Treatment options include:
Ortho-K Vision Correction
Orthokeratology (or Ortho-K) is a type of contact lens wear which has been practiced by our optometrist Mr Alex Petty for many years. Ortho-K Vision Correction involves wearing a custom-designed contact lens overnight which reshapes the surface of the eye, giving clear vision the next day without the lenses. As well as being convenient for the patient, the treatment actually slows and in some cases stops myopia progression. Research shows a range of 32%-100% slowing of myopia progression depending on the study. Most reports suggest an average of a 50% reduction in the rate of myopia progression with Ortho-K wear.
It should be noted that these studies used Ortho-K lenses designed for adults to see well. The newest Ortho-K lenses that are designed for children's myopia control show a better myopia control effect than normal Ortho-K lenses. Results in Alex's patients and from other myopia control practices in Australasia using these cutting edge designs show complete halting of myopia progression in some patients.
How does Ortho-K Vision Correction slow myopia?
When myopic eyes are corrected with conventional spectacles and contact lenses, light entering the eye centrally will focus at the retina; however, light entering off centre will focus behind the retina. This is thought to stimulate lengthening at the back of the eye as the retina tries to reach the focal point behind the eye, worsening the condition.
Ortho-K lenses can slow this growth by changing the shape of the eye surface, allowing central light to focus accurately at the retina and off-centre light to focus in front of the retina. The retina will no longer 'attempt' to elongate (see image).
Please refer to our Orthokeratology page for more information about how this treatment works.
Atropine drops have been used for many years to control myopia; however, until recently they have been prescribed at a normal concentration of 0.5% - 1%. Atropine at this concentration causes loss of focusing in young children for near tasks and dilates the pupil significantly, leading to light sensitivity.
Studies over the last decade have found that much lower concentrations of atropine, such as 0.02%, have a comparable reduction in myopia progression, without any noticeable effect on pupil size or near-focusing. For example the ATOM2 study showed the myopia control effect of 75% reduction for the 1%, 0.5% and 0.1% concentrations and 65% reduction with 0.01%. Studies have told us that 0.02% is the highest concentration of atropine that shows no significant change to near focusing or pupil size in children, and has no reported allergic side effects.
Recent reports have suggested that while low-dose atropine strengths like 0.01% that are widely used decrease the change in the spectacle prescription over time, the effect is less significant when evaluating the slowing of eye length - the key determinant of the risk of secondary eye disease later in life. Higher low-dose concentrations of 0.02% and 0.05% show better control of axial eye growth and are therefore being used more often for children with myopia progression risk.
How do atropine drops slow myopia?
It was initially thought that as atropine drops paralysed the focusing muscles of the eye, this was the reason for the myopia control. Our understanding now suggests that the atropine molecule affects a receptor in the tissue of the back of the eye, signalling the eye to stop growing excessively. This mechanism is still being studied around the world.
Atropine drops need to be instilled nightly and can be combined with Ortho-K therapy to theoretically maximise the myopia control effect. Visual side-effects are uncommon at the low concentration of 0.02% and 0.05%, and general side-effects highly unlikely. Atropine drops need to be specially requested by your optometrist from a compounding pharmacy in Auckland as they are not readily available at concentrations below 0.5%.
Soft Contact Lenses
Certain types of soft contact lenses have been used in the past to try to control myopia, although results have been underwhelming. Bay Eye Care has access to a range of modern multifocal soft contact lenses that are more appropriate for children and teenagers at risk of progressive myopia. These include the Coopervision Misight 1-Day lens and VTI’s NaturalVue 1 Day multifocal.
Misight lenses were designed by a research team at Auckland University, specifically for myopia control. The most current study into these lenses shows over a 50% reduction in myopia progression and eye growth compared to a normal soft contact lens over a 3 year period.
If Ortho-K lenses are not suitable for your child, then soft multifocal contact lenses like Misight and NaturalVue are an excellent option to provide reasonable myopia control effect, while giving improved vision during wear. They work to control myopia progression in a similar way to Ortho-K lenses; by changing the way off-axis light is focused on the back of the eye. The main difference with soft lenses is that they are worn during the day rather than at night.
Spectacle lens options
As mentioned previously normal spectacles offer no myopia control benefit. Individuals that are already short-sighted and who show problems with their eye coordination (tendency for their eyes to turn in more than required when reading) or focusing (a child's eyes do not focus enough on a near task they are looking at) may benefit from wearing progressive addition spectacles lenses or bifocals (normally used for older patients who cannot focus on near print) for a myopia control benefit. The near conditions mentioned above are tested by your optometrist during your appointment. Studies are varied but suggest a reduction of myopia progression in the range of 12-55% with these lenses. There are newer spectacle lens designs created for myopia control coming soon that may provide better results for certain patients.
As well as the above treatments, there is some evidence that spending at least 2 hours a day outside in natural light may decrease the chance of myopia progression. There is an excellent website by Richard Anderson which explains in detail all aspects of myopia control with the relevant research included.