What is Myopia?
Myopia is a condition that results from the light being focused in front of the retina (as opposed to right on the retina) due to excessive axial length (length of the eyeball) usually from the eyeball growing too fast. Myopia or nearsightedness is when objects at near are clear but things at a distance are blurry. Myopia happens in those eyeballs that are slightly longer than average. As the eyeball continues to grow and elongate, it becomes more and more nearsighted. This is why most nearsightedness develops around growth spurts in young children and pre-teens. The younger the child is when they become myopic, the more myopic they will end up. It is especially important to help those children who become near-sighted early in their life. Myopia progression is the fastests in children between the age 7 to 10 years of age (Tricard et al, 2022). This is why the earliest possible intervention is ideal. Natural progression of myopia can continue into college years however, most of the worsening occurs in children between the ages of 8-12.
Axial elongation is the main risk factor for development of pathological complications of myopia in adulthood. https://iovs.arvojournals.org/article.aspx?articleid=2164126. Myopia is the most common refractive error among children and young adults worldwide but the most important factor is not simply to correct it with glasses or contact lenses but to try and minimize the higher risk of ocular health consequences due to high myopia. Pathological risk factors associated with increased axial length/high myopia still remain even when an adult has a refractive surgical or laser procedures such as LASIK. High Myopia or pathological Myopia is refractive error > -6.00D, axial length of >26mm. These eyes have an increased risk of visual impairment and ⅓ will experience blindness or low vision. https://pubmed.ncbi.nlm.nih.gov/25208857/
Nearsightedness increases risks of eye diseases and complications such as glaucoma, myopic macular degeneration, cataracts and retinal detachments as they get older. Once Myopia has progressed, the risk of these diseases for the child increases.
Myopia is increasing around the world. It is projected by the American Optometric Association that half of the world’s population will be myopic by 2050. In the U.S., prevalence of Myopia has almost doubled from 25% to 42% over the last two generations (since the 1970’s). Myopia is a significant public health concern. In 2015, lost productivity due to visual impairment from uncorrected myopia and myopic degeneration was estimated at about $250 billion. https://pubmed.ncbi.nlm.nih.gov/30342076/.
Over the years, myopia is increasing due to higher uses of devices among young children and less time spent outdoors. Most recently, during the COVID-19 pandemic during which most children had an increased screen time and near work load, there was a significant myopic shift for kids 6 to 8 years old. https://pubmed.ncbi.nlm.nih.gov/33443542/
What Causes Myopia?
There are multiple factors that play a role in how myopic/nearsighted a child will be and how much a child’s eyes will change.
Genetics – If one of the parents is nearsighted, a child’s chances increase, if both parents are nearsighted, a child’s chances nearly double. Asian children tend to be at the highest risk for developing Myopia with 80% of the Asian population being myopic.
Near work – the more time kids spend with near tasks (such as reading and screen time), the more nearsighted they tend to be. This is one of the main reasons that nearsightedness is increasing all around the world in recent years. In a study of more than 1,000 children aged 7 to 9, those children with higher time spent reading were more likely to be myopic. https://pubmed.ncbi.nlm.nih.gov/11818374/
Outdoor – Kids that spend more time outdoors, tend to be slightly less nearsighted. In a study, kids that spent at least 2 hours outdoors each day, showed slower myopic progression than those who did not. We are not 100% sure yet if it is the lighting or more focusing on far objects that helps in this case but outdoor time is very important. Increased time outdoors is effective in preventing the onset of myopia as well as slowing down the myopic shift but not as much in slowing down progression in an already Myopic eye https://pubmed.ncbi.nlm.nih.gov/28251836/. It is important for young children, especially those with high risk factors for myopia (such as genetics) to be spending as much time outdoors as possible.
Other Things to Consider
Diet – There are no direct studies yet on diet and myopia progression but there are many speculations by experts that say a bad diet likely has a link to progression of myopia.
Preventative Eye Care – Take your child to the eye doctor to have their eyes checked every year starting at school age (or earlier if any problems are suspected). This is when eyes tend to start changing in nearsighted children.
Lifestyle – In addition to the interventional prevention with your eye doctor, don’t forget to increase outdoor time with your child and reduce the screen time. In addition, good lighting as well as good posture is important while your child is doing near activities such as reading.
Can anything be done to reduce the severity of my child’s Myopia?
If your child’s eyes are getting ‘worse’ every year, is there anything that can be done? YES, though not a guarantee to stop progression, we have a few options to help greatly slow down myopia progression (the eyes getting worse and glasses getting thicker every year). The many different ways we try to accomplish this is called Myopia Control. No single treatment has been shown to completely prevent or stop Myopia. The interventions we have are not a guarantee to stop all changes but to greatly reduce the rate at which the eyes are getting worse. Envery diopter we can prevent makes a great difference in not only the vision your child will have but also a much reduced risk of developing potentially visually impairing consequences of high Myopia. Reducing a patient’s final degree of Myopia by 1.00 D reduces the lifelong risk of a complication such as myopic Maculopathy by 40%, regardless of the final Myopia outcome. https://pubmed.ncbi.nlm.nih.gov/31116165/
In addition, the earlier we intervene, the better results we get. Myopia control interventions are the most successful at a younger age, when the progression rates are the highest.
Through the various Myopia Control interventions we seek to slow down the progression or worsening of the eye but any current Myopia (that has so far occurred) cannot be reversed. Also, each child responds differently to the different modalities of Myopia Control and success achieved may vary, even between siblings with similar genetics and those starting out with similar amounts of Myopia. The goal is not to stop all change, we do not have knowledge or the technology to do so at this time.
Myopia Control Methods
There are multiple Myopia Control methods available for children who are progressing/worsening in their vision. Most children progress between the ages of 6 to 12 but for some, myopia does not start till later and continues to progress in their 20s https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2787671. It is beneficial to continue or initiate myopia control even in adulthood especially for those pursuing higher education or mostly at near work. For some, axial elongation can continue even beyond age 50 https://pubmed.ncbi.nlm.nih.gov/33909032/.
There are multiple methods available and what the doctor recommend for your child will depend on the child’s age, their risk factors as well as their current amount of myopia.
As stated before, passively correcting myopia with conventional glasses and/or contact lenses is NOT an intervention in slowing down myopia progression. Children wearing Single Vision (conventional) glasses or contact lenses will likely continue to change and worsen at a rate of progression at about -0.75 D per year. For 7 year olds it is about -1.00 D of progression and about -0.50 D of progression for 12 year olds (Donovan et al, January 2012).
Myopia Control methods include specially designed glasses, specially compounded eye drops, specialty contact lenses and orthokeratology. All these methods of Myopia Control attempt to optimize the clear vision across the entire retina (in the back of the eye) which reduces the stimulus to the eye to continue growing at a higher than normal rate. Re-distributing the clear image on the entire retina (both centrally and in the periphery) acts as a stop signal for the abnormal eye growth.
Myopia Control methods can be started as soon as any progression or worsening even in slight myopia is noted. Some doctors start treatment when the child is -0.50 D myopic, others start as soon as any progression is seen in myopia or axial length that is faster than average for that age. Yet some doctors start treatment in high risk children when lower than usual amounts of hyperopia are found for the child’s age. Normally, children are born hyperopic or farsighted and as part of their normal development and eye growth, farsightedness reduces and ideally the child is left plano (no refractive error). If a child reduces in farsightedness at a faster rate than usual for his or her age or if the eye grows faster than average, Myopia Control interventions can be initiated. Farsightedness acts as a buffer in the early years, therefore, lower hyperopic buffer is a strong, single predictive risk factor of myopia as found by researchers at Ohio State. A child at 6 years old with +0.75 D or less has a significant higher risk of developing myopia. Your child’s eye doctor may recommend more frequent monitoring. Also, increase time outdoors, take frequent breaks from near and focusing activities, especially screens.
The eyeball growing too long too fast is another risk factor for myopia progression, axial length measurement is a great tool to catch early myopia development and those children who will end up myopic. Axial elongation is a risk factor.
When your child has been identified in the high risk category for progression of myopia, an overview of Myopia Control options will be provided as well as the best treatment option recommendation specifically for your child. An Initial Myopia Management Assessment will be scheduled where multiple in depth measurements will be done, all Myopia control options will be discussed, and the best treatment option for your child confirmed.
Even though Myopia Control is a very important topic and will greatly reduce the financial burden on our society in the future, it is not yet covered by insurance. While conventional glasses and contact lenses are (at least partly) covered by insurance, special contact lenses, glasses and the fitting is not yet covered by insurance at this time. You are however, able to use health spending and flex spending accounts, as well as Care Credit. Also keep in mind, the cumulative cost to conventional glasses and contact lenses as the child grows and the prescription becomes stronger and stronger to address the progressive Myopia.
There are 4 main methods to slow down the progression (worsening) of Myopia:
Suggested reference list for Parents
1. Holden et al 2016
2. COMET Group 2013
3. Flitcroft 2012
4. Tideman et al 2016
5. Chua et al 2016
6. Brennan et al 2020
7. Gifford et al 2019
8. Bullimore& Brennan 2019
9. Stapleton et al 2008
10. Bullimore et al 2013
11. Arshad et al 2019
12. Walline et al 2007a
13. Bullimore 2017
14. Walline et al 2007b
15. Yam et al 2019
16. North & Kelly 1987
17. Yang et al 2021
