Myopia Control

Myopia, or shortsightedness, results in difficulty seeing distance objects clearly. This occurs because the focusing power of the eye is too strong or (more commonly) the length of the eye is too long. While blurry distance vision can be corrected with spectacles or contact lenses, the real issue is the structural changes at the back of the eye which increases the risk of irreversible eye disease.1,2 The higher the level of myopia, the higher the risk.

Our optometrists offer a wide range of treatment options to slow the progression of myopia. If you would like to find out more, book an appointment at our Adelaide or Woodville practices or speak to our friendly staff.

Assess My Child's Myopia Risk Here

How prevalent is myopia?

The prevalence of myopia is increasing drastically, with the World Health Organisation considering it an epidemic. Currently, 30% of the Australian population is myopic and it is estimated that by 2050 half of the worlds population will be myopic.3 Some groups of people are more likely to be affected than others, with both genetic and environmental factors playing a role in the development and progression of myopia. Those that are higher educated, those that live in densely populated areas and those of Asian descent tend to be more adversely affected.4,5

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How does myopia affect the eye?

In myopic eyes, light is focused in front of the retina rather than on it, causing blurry distance vision. This usually occurs because the eye is physically too long. Myopia is a progressive condition, meaning over time the eye continues to grow longer, increasing the level of myopia over time. As the eye grows, the tissues at the back of the eye become stretched. People with high levels of myopia are at an increased risk of irreversible eye disease (e.g. retinal detachments and glaucoma).1,2 Myopia can develop at any age but the younger the onset the higher the risk of progression to high myopia.

What are the associated risks of myopia?

Historically, low myopia was considered a normal variation of the eye. Now there is a clear distinction between the two types of myopia:

  • Low myopia between -0.50 and -6.00 D 6
  • High myopia beyond -6.00 D6

The main difference between low and high myopia is the association with eye growth, or axial length. The best way to assess the risk of eye disease from myopia is to measure axial length and monitor the change over time. Once the axial length exceeds 26.5mm, the risk of eye disease such as glaucoma and retinal detachment is significantly increased.2 This is why slowing down the progression of myopia is so important.

How bad are the risks, even just for low myopia?

A study published in 20121 on the interactions of several factors on myopia found the following:

“Myopia in the so-called ‘physiological range’ represents a major risk factor for ocular disease that is comparable with the risks associated with hypertension for cardiovascular disease or with the risks of stroke from smoking more than 20 cigarettes per day. For retinal detachment and myopic maculopathy, myopia carries a risk far in excess of any identified population risk factor for cardiovascular disease.”

These conditions are far from rare: myopic maculopathy, a progressive condition causing breakdown of retinal cells, is the forth most common cause of visual impairment in the UK, ahead of diabetic eye disease.7 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. The chance of a permanent vision loss in patients with axial length of more than 26mm is 25%, compared to 3.8% in eyes less than 26mm.2 If we can stop the progression of myopia into these high levels then a significant amount of blindness can be prevented.

Case study: Alex Petty

The personal case of one of our previous optometrists, Alex Petty, highlights why myopia control is so important. Alex developed myopia at the age of 9. This progressed throughout his teenage years, eventually stabilising at a high -7.50 D in each eye. As a result, Alex suffered two retinal detachments in his left eye in 2009 and another in 2014 in his right. Fortunately, through timely surgery the damage was controlled with only slight vision loss.

If Alex had access to myopia control treatments when he was a teenager, it is unlikely his prescription would have worsened as quickly and these ocular emergencies might have been prevented. His experience has fuelled a passion to treat young people with myopia and prevent eye disease later in their lives.

How can myopia be controlled?

Standard spectacle or contact lenses will make the distance vision clear but will do nothing to stop the lengthening of the eye or decrease the risk of permanent eye disease. While myopia cannot be cured or reversed, we can slow down and even stop its progression, making early detection and intervention critical. Current evidence shows that orthokeratology, atropine eye drops and multifocal contact lenses are the most effective tools to control myopia.

To find out more, make an appointment with one of our optometrists.

Innovative Eye Care’s myopia control treatment options

Orthokeratology

Orthokeratology (or ortho-K) is a type of contact lens wear which has been practiced at Innovative Eye Care for many years. Ortho-K involves wearing a custom-designed contact lens overnight which reshapes the surface of the eye, providing clear vision the next day without the lenses.

As well as being convenient, ortho-K actually slows and in some cases stops myopia progression.8,9 As the surface of the eye changes, so does the point at which light entering it is focused. Myopes focus light behind the retina, so when reshaped, the light focuses on the retina and the eye no longer attempts to elongate.

Ortho-K has been proven to slow myopia progression by 32-100%, depending on the study.8,9 Most reports suggest an average of a 50% reduction in the rate of myopia progression with ortho-K contact lens wear. Results in our practice and from other myopia control practices in Australasia show complete halting of myopia progression in some patients.

Atropine drops

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 leading to light sensitivity. For young patients that show aggressive myopia progression we will still recommend 1% atropine in order to best control their myopia progression. These drops are used in conjunction with tinted transitions progressive lenses to give protection from bright light and the ability to see for reading tasks.

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.

It was initially thought that as atropine drops paralyse 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 choroid or sclera of the eye (the vascular and structural layers of the eyeball), signalling to the eye not to continue to elongate. This mechanism is still being studied.

Atropine drops need to be instilled nightly and can be combined with ortho-K therapy to maximise the myopia control effect. Visual and general side-effects are highly unlikely at 0.02%. Atropine drops will need to be specially formulated at a compounding pharmacy as they are not readily available at concentrations below 0.5%.

Multifocal contact lenses

Certain types of soft contact lenses have been used and developed to control myopia. Multifocal soft contact lenses are typically used by people over 40 to improve their near vision. These have a similar peripheral area of steepening on the lens like ortho-K, although at a lower level (maximum +3.00 D, whereas the ortho-K example above shows a +8.00 D difference). As a result, when these soft contacts have been used by young patients, studies have only reported a modest range decreased progression of 29-45%.

Specialised soft contact lenses called MiSight (Coopervision) show a 40% reduction in myopia progression. Similarly, a recent case study of VTI brand NaturalVue soft lenses showed that 91% of participants showed an over 70% decrease in myopia progression. If ortho-K lenses are not suitable, these soft contact lenses may be discussed by your optometrist as an alternative option, and may be used in conjunction with atropine drops.

Spectacle lens options

As mentioned previously, regular spectacles offer no myopia control benefit. In some individuals that are myopic and progressing and that show a near esophoria (tendency of the eyes to turn in more than required when reading) or an accommodative lag (eyes do not focus close enough when reading) then progressive addition spectacles lenses may offer some myopia control benefit. The near conditions mentioned above are tested by your optometrist during their appointments. Studies are varied but suggest a reduction of myopia progression in the range of 12-55% with these lenses.

Myovision spectacle lenses are specially designed for controlling myopia but studies suggest they only slow progression by 0-30%. As a result they are infrequently used.

Other considerations

Apart from active interventions, there is also sufficient evidence for the modification of lifestyle factors of time spent on near work and time spent outdoors. Less near work, or more regular breaks plus more time outdoors in natural light are protective against eye length growth.

There is an excellent website by Richard Anderson (myopiaprevention.org) which explains in detail all aspects of myopia control with the relevant research included.

Axial eye length is the best metric of risk and progression for myopia. It has the with the least variability and directly relates to the disease processes that myopia can create. If you are concerned about your child’s eyes becoming progressively short-sighted, please contact our friendly team to arrange a consultation with one of our optometrists to discuss their myopia and what may be done to arrest this progression.

References
  1. Flitcroft, D. I. (2012). “The complex interactions of retinal, optical and environmental factors in myopiaaetiology.“Progress in Retinal and Eye Research31(6): 622-660.
  2. Willem, J. et al. (2016) ‘Association of Axial Length with Risk of Uncorrectable Visual Impairment for Europeans with Myopia’. JAMA Ophthalmol. 134(12): 1355-1363.
  3. Institute, W. H. O.-B. H. V. (2016). ‘The Impact of Myopia and High Myopia.’ Report of the Joint World Health Organisation: Brien Holden Institute Global Scientific Meeting on Myopia.
  4. Chen-Wei, P. Ramamurthy, D. Seang-Mei, S. (2011). ‘Worldwide prevalence and risk factors for myopia’. Opthalmic and Physiological Optics. 32(1).
  5. Goldschmidt, E. Jacobsen, N. (2013). ‘Genetic and environmental effects on myopia development and progression’. Cambridge Ophthalmological Symposium. 28(1): 126-133.
  6. Flitcroft, D. I., et al. (2019). “IMI-Defining and Classifying Myopia: A Proposed Set of Standards for Clinical and Epidemiologic Studies.“InvestOphthalmolVis Sci60(3)
  7. Wong, T. Y., et al. (2014). “Epidemiology and disease burden of pathologic myopia and myopic choroidal neovascularisation: an evidence-based systematic review”. Am J Ophthalmo. 157(1): 9-25.
  8. Na, M. Yoo, A. (2018). “The effect of orthokeratology on axial length elongation in children with myopia: Contralateral comparison study”. Jpn J Ophthalmol. 62(3): 327-334.
  9. Hiraoka, T. et al. (2012). “Long-term effect of overnight orthokeratology on axial length elongation in childhood myopia: a 5-year follow-up study”. Invest Ophthalmol Vis Sci. 53(7): 3913-3919.