Myopia everywhere
If you wear glasses or contact lenses to view distance objects then you might be familiar with the term myopia. Myopia, also referred to as being nearsighted, is described when an individual requires concave lenses placed in front of their eyes to see clearly. It has become a topic of interest for vision scientists as more people are needing glasses. In the United States as much as 33% of adults have myopia,1 and it has been recorded as high as 80% of young adults in Taiwan.2 There is evidence that genetics plays a role in myopia development, however that cannot possibly explain the emergence of myopia when 100 years ago few people required glasses. Since completing 100 hours of the Optometric Extension Program Foundation’s clinic curriculum for vision therapists, I wish to write on my view of myopia progression, including it’s cause and how behavioral optometrists can be part of the solution.
I call it the myopia sickness. That is my term for when an individual presents for an eye exam and I measure their myopia has worsened. Academically, I was taught that this only happened to children, and it was normal – both of these are false. Although uncommon, myopia progression occurs in adults. It causes frustration, insecurity, and despair. Optometrists commonly answer the questions: “when will my eyes stop getting worse?” or “Am I going to go blind?” Myopia is a disability, requiring the individual to keep glasses on their face at all times in order for function. Worsening myopia is not normal, it is product of a near-point visual dysfunction.
How did we get here?
What is different about our environment, our careers, and our hobbies from what people enjoyed 100 years ago – lots!. One hundred years ago there were no smart phones or tablets – there were no computers at all. People spent more time working outdoors farming, hunting, fishing, or as carpenters. Children spent less time doing near vision tasks.
Understandably our vision has adapted to the stresses of our new environment of electronics, news feeds, and novels. To the behavioral optometrist reading is a biologically repulsive task. Our eyes were not meant to focus at near for extended periods of time without significant stress on our visual system. If our visual system cannot cope with the increased stress it can respond in a number of ways: 1) develop a reading problem 2) develop strabismus or 3) develop myopia to relieve the stress. Myopia is our vision’s response to unnatural near-point stress that it cannot cope with. Studies have even shown reduced myopia in children that spend more time outdoors.3
Often the number one complaint for someone with worsening myopia is distance blur. So naturally when they present to their optometrist they ask for stronger glasses. Most optometrists have been trained to comply and achieve optimal distance acuity – you are familiar with the term 20/20 vision; however prescribing stronger lenses for distance vision comes at a cost. For most myopes the full distance prescription increases the stress on the visual system when doing near tasks. I have read blogs that blame optometrists for their worsening vision – I will respond by saying myopic progression in adults is still uncommon and most times offering the full spectacle prescription does not do harm to the patient. Most patients desire seeing the letters on the 20/20 row; however, I will agree that optometrists should offer more dialogue about near vision correction to protect from myopia progression.
Let’s make it better
So how can we work to stop myopia. For the individual there are a number of lifestyle and postural changes that can be made. This includes reducing our time spend looking at a screen. It is also believed that taking more frequent breaks and practicing distance viewing exercises can be helpful – an example of this is the 20/20 rule: taking a break after 20 minutes of a near-vision task to look view in the distance something greater than 20 feet away. Another lifestyle change might be adopting a greater acceptance of distance blur. A full distance prescription improves clarity when distance viewing, however for most people less than 10% of their day is spent viewing in the distance. Most of our time is spent indoors, therefore it might be more appropriate to have a task specific prescription to improve visual comfort and efficiency – this can also produce a reversal of the myopic progression. Other postural changes should be considered, including holding near material at Harmon distance (the distance from our elbow to our knuckle) or using a more upright posture to reduce stress on our neck and shoulders. A slant board is an excellent device to improve posture and reduce stress on the visual system.
How your eye doctor can be part of the solution
Lenses can also be a powerful tool to reduce myopia progression or even reverse myopia. Correcting a person for near activities can be helpful at reducing visual stress. This might come in the form of a bifocal or simple reading glasses. It has been documented that this is an effective treatment for reducing myopia progression. Dr. Darrel Harmon discovered that myopic and hyperopic children adapt different postures when reading, and that the use of lenses can alter a person’s posture by either increasing or decreasing muscle tonicity.4
In my personal journey I am pleased that I have cut my distance prescription back 0.75 diopters in less than 2 months. I wear a bifocal to reduce near vision strain. In the future I plan to reduce my astigmatic correction. I have not found a patient that actually wants their myopia to worsen, so I thought it would be valuable to write this post. I hope that it was easily understood and that colleagues reading this question what they’ve been taught about prescribing.
There are of course other alternatives to slow myopia progression including vision therapy, orthokeratology, MiSight contact lenses and atropine penalization; however none of these treatments have been tested in adults to understand whether they will slow myopia. Visit our website to learn more about these other treatments offered at North Peace Optometry Clinic.