Pediatric Myopia: an Epidemic?

Things have changed since I was a kid. We played outside till dark, explored in the woods, got dirty, built forts, watched the occasional “after school specials” and who could forget the cartoon Saturdays. Today kids have visual stimulating gadgets everywhere. Of course, we had the Atari, Nintendo and its Game Boy in the 90s, paving the way to the XBOX, Playstation and others. But its a different world today for sure – driven by handheld devices that are constantly drawing attention from most every kid, whether in restaurants or a big box store keeping Johnny hypnotized while mommy or daddy gets the shopping done. Is the “technogadget, information at your fingertips world” we live in today effecting our youngsters eyes? I would say absolutely, and the evidence is in the research.

According to the journal Ophthalmology (2016), “Half of the worlds population (nearly 5 billion) will be myopic by 2050, with up to one-fifth of them (1 billion) at a significantly increased risk of blindness if current trends continue.”1

Nearsightedness, or myopia, is a condition of the eye where light focuses in front of instead of on the retina. This causes distance objects to become blurry while close objects remain clear. Eyestrain as a result of squinting improves the clarity of distance objects, and over time the focusing system of the eye becomes weak from exhausting this mechanism. The decrease in distance vision over time and headaches are a result. Eyestrain is also a result of excessive near work — reading for hours a day or using computers or phones excessively (where the definition of “excessive” is debatable). The fact that distance vision becomes worse over time is just part of the problem with this eyestrain epidemic. The eye’s ability to focus like a camera is also degraded. We’ve all heard the phrase “my arms aren’t long enough” or “the print keeps getting smaller” etc. due to inability to focus on objects nearby after forty or so birthdays. This complaint is now being heard or revealed in a comprehensive eye examination by much younger patients. I believe in part to the over-stimulation and constant use without breaks. This near demand on our eyes today is worsening compared to ten years ago. To be realistic, there seems to be no way around the world of electronic communication and the social network phenomenon – desired or not. It is widely accepted and frankly not debatable that myopic progression is a high priority.

Seeing that the tech world is only becoming the rule and not the exception, we should be aware of its effects on our eyes. Often I am asked “What restrictions should I place on my child’s screen time?” or “How can we prevent his/her eyes from worsening?” These are good questions and with the evidence produced from collective myopic control studies we now have at our fingertips optimum guidelines and treatment interventions to slow down the progression of these myopic changes.

To date there is no actual cure for myopia. There are ways to improve myopic vision degradation up to the time it is corrected, but vision can and most likely will change over time. The human eye will stop growing at or around puberty, but very little change in the length of the eye can cause significant change in myopia. This is why refractive surgeries like LASIK can only be considered when the length of the eye is less likely to change. So therefore contact lenses, spectacles, or the various refractive surgeries may not be the only

treatment needed throughout ones life, but with the myopic “epidemic” we are seeing today, combinations of the above treatments are needed. This is where MYOPIC CON- TROL comes on the scene. We have desperately needed an intervention plan for decreasing the PROGRESSION of vision loss from myopia in children so that they will not be at a higher risk for myopia induced ocular disease, let alone the poor vision and the lifestyle changes it accompanies.

What Are Some Causes of Myopic Progression? There isn’t necessarily one cause of myopic progression but rather a combination of factors. Parents that are nearsighted are more likely to have myopic offspring, but not always. It’s certainly a predestination NOT a destiny. It may be that parents who preferred to read a lot have kids that prefer the same activity. We do know that there are factors that contribute but how they vary from one child to another is difficult to gage. Factors like excessive reading (2-3 hours at a time), long term computer use, and some evidence that diet may be a variable. For the purpose of this article we will discuss some interventions. Independent of the causes, the facts are that myopia and its progression over shorter time intervals are worsening. Just like you don’t have to understand the physics of how a bike works to actually ride one, we’ll focus on how to decrease this problem at hand.

Why is Myopic Control Important? There are considerable health risk with significant myopic changes, especially if at a high rate. As mentioned, the axial length — or length from front to the back of the eye — is the most influential variable in myopia besides the curvature of the cornea. When the axial length of the retina becomes elongated, there are areas that become stretched and ultimately too thin. Imagine blowing up a balloon. The more air that is blown in, the longer and thinner the balloon becomes. Like all organs the retina’s growth is reg lated by homeostatic control mechanisms and unlike other organs the eye relies on vision as a principal input to guide growth. This thinning of the retina tissue causes significant fall out. The retina is in a way the circuit board encompassing a complex network of nerve fibers and cells that together make up an enormous grid for delicate chemical reactions that produce vision as we know it.

Vision Threatening Ocular Disease and Disorders Associated with Myopia

Degenerative Myopia – When the elongation of the axial length reaches a certain level or lengthens at a high rate it can become pathological. The risk for retinal detachment is higher due to thinning retina at a rate the eye cannot repair or control its repair mechanism quickly enough. Degenerative myopia can be detected with a dilated exam and there are particular changes the eye care

specialist will detect. This includes macular edema (fluid build up in the center of the retina), “stretch marks” or lattice, holes within the outer segments of the retina, pigment changes called “lacquer cracks” and large optic nerve disc which appear to be tilted with loss of tissue around the nerves.

Retinal tears and retinal detachments – This is a painless separation of the retina, particularly the layer responsible for converting light to image. A retinal detachment can be repaired in most cases if medical attention is achieved in a timely manner. Symptoms of retinal tear and /or detachment are flashes of light that are sudden and profound, subsequent floaters, distorted images that do not return to normal within seconds, and most dire the “veil” or “curtain” affect producing dark visual field loss that increases with time.

Cataracts – Filmy vision over time that worsens in magnitude is most common symptom of a cataract. A longer eye causes entering light to scatter and in turn causes the lens in the eye to become more dense. This increased density scatters light and ultimately allows UV light to change the lens by distorting polymer chains. Additionally, the elongation of the retina deprives the posterior lens of nutrients and therefore clouding the back surface.

Glaucoma – This is an ocular disease which causes one to lose peripheral vision. There are a few ways this can occur. The common finding in each mechanism is the thinning or loss of retinal nerve fiber and retinal ganglion cell complex (GCC). There have been several studies that relate risk of myopia and glaucoma. The most agreed is that the GCC is altered, again from being stretched. The GCC is synonymous with a complex wiring system that connects the all important optic nerve with the macula. If this layer is stressed the macular framework will be unable to remain stable. The exact pathology of how the ganglion complex is altered by stretching of retinal layers is not known but the risk of glaucoma increases as the

axial length increases. Many studies have established that relationship most notably The Beaver Dam Eye Study.

Methods for Myopic Control Research in this area of myopic control has become a global urgency. As more information and facts are determined, professionals on the clinical level are implementing and monitoring the results. As we stand today there are currently five general clinical techniques that are universally accepted as “control methods”. At Schaeffer Eye Center (a MyEyeDr affiliate) our very own Dr. Nicholas Onken, pediatric specialist, has experience with the latest methods.

1. Getting outdoors more. This one seems almost like its not a real treatment but actually does make sense. A little vitamin D and getting dirty with some tree climbing and fort building never hurt a kid (too bad). This kind of activity relieves the eye from over focusing. There is truth to “avoiding the stressor” just like a newly discovered allergy or the co-worker that causes a blood pressure spike.

2. Bifocal or progressive glasses. This idea is centered around the theory that assisting the child’s accommodation mechanism by doing a little of the “work” up close will eliminate some of the stress, and also to cause a “peripheral retinal blur” which prevents the stimulus for the retina to grow or stretch. Executive design lenses (bifocals measured at the center of the pupil) have shown more reduction in myopic progression than progressive lenses – 33% reduction in one study2. Each case will have its unique story as we are all very different and research is not biased concerning a personality or a child’s likes and dislikes. Results from a study may say “x” but compliance with a line vs no-line progressive lens may become a real concern for one individual and not another. Convincing a twelve year old to start wearing a bifocal may be a hard sell and all the years of being the cool doctor are on the line. This can be combated by the fact that an executive lens is actually easier to use since there is no image jump and the child can operate the design almost immediately.3 Dr. Onken points out “many adults are hesitant to use multifocal glasses because they’ve heard that it’s hard to adjust to them. This has never been a problem with kids – they just roll with it!”

3. Multifocal Soft Contact Lenses. This is my personal favorite. For those kids who show a mature character – the overachievers – this seems to be a great option. It’s also very effective as the latest results published to date is a 48% reduction in myopia vs the control group of the same age4. The contacts used in this method are multifocal with a specific design for distance and near separated within the lens. This design can be alternating concentric rings, distance in the middle and near on outside, or translating as near in the bottom and distance on top. This is an example of how the myopic control studies have

changed the paradigm and more options are available than once thought. This premise is consistent with the spectacles as well. The design discourages axial length growth by blurring the outer retina. In the clinic I reside, all cases have shown an obvious decrease in myopia progression compared to those in their age group, even in the more myopic youngsters. A couple mind boggling case studies where we fit multifocal contacts, one age 6 and one 7, come to mind. When these patients reached their three year visit, the resulting myopic magnitude was half that of kids at the same age and refractive error with no treatment. Once a child masters the daily insertion and removal routine and maintains appropriate hygiene, they are usually bought in. Dr. Onken’s experience with fitting kids confirms this. “With contact lens wearers, children are the lowest risk population for eye infections related to contact lens wear. My youngest contact lens wearer is 3 years old, because contact lenses work better than glasses for many visual problems, including the control of myopia”.

4. Ortho-K, Kerotology. This is a rigid gas permeable lens that is specifically designed to reshape the outer portion of the eye (cornea) while one sleeps. The patient then removes the lens and the vision has been corrected secondary to flattening. The cornea is spongelike and will revert back to its original shape over time if the lens is not worn. This is a more advanced method for myopia control as it requires a certification and many patient encounters to reach expert level. This is becoming a more accepted control both professionally and from the patients perspective. The peripheral retina blur is constant throughout waking hours and the corneal epithelium is the only layer of cornea “changed” – making this method low risk for any permanent damage to the cornea if lens is ill-fitting or not ideal. After seven days the corneal epithelium is completely turned over. One downside to ortho-k is the difficulty for some to adapt to the initial fitting, especially with a younger child. The lens material is more difficult to adjust to initially but if educated thoroughly and properly, motivation and dedication will drive the patient to success. This method does yield a healthy 45% reduction in myopic control, similar to multifocal contact lenses5.

5. Atropine. This is a pharmacological method that involves the use of a drop with cycloplegia effects. Cycloplegia is the paralyzing of the ciliary muscle in the eye resulting in the loss of focusing ability. This method of myopic control is using a pharmacological intervention – one drop in each of the eye daily. The temporary paralyzation of the lens prevents accommodation and in doing so decreasing the stimulus to elongate. Statistically this method is the most rewarding but carries a few concerns8. A couple drawbacks are most people and especially children wouldn’t line up for drops that cause a little blur and the drop is off label – requiring very careful attention to pharmacological interactions to medicines since this

is a longterm regiment. There are possible central nervous system and cardiovascular implications to be aware of although many atropine supporters suggest very little concern. As a pro argument the most effective concentration was determined to be 0.01%, diluted significantly from the 0.5 - 1% atropine used in optometric exams to treat some injuries with inflammation. The appropriate concentration of 0.01% when used 1 drop a day, can effectively decrease progression of myopia by 68% over a 5 year span.5 Additionally, this method must be adhered to and constant positive reinforcement is necessary. Dr. Onken agrees that “the hardest part is remembering to do them consistently — and a way to keep consistency is putting the drops in when the child is asleep, as it often reduces the stress of the event”.

Conclusion There is no doubt that myopia progression rates are on the rise globally. We must be aware of the risk these rates cause on our eyes – specifically our children. We need to ensure that our children are receiving comprehensive eye examinations and creating a dialogue with parents about the risk of myopic progression and intervention possibilities. Optometrist must not only realize the severity of this nearsighted world but get on board with treatment options. Dr. Onken, and many others, are making efforts to improve this concern. Dr. Onken expressed his passion stating, “As a pediatric specialist, one of my biggest concerns is the rapid progression of myopia in today’s kids. Both genetics and our modern day lifestyle contribute to this alarming trend. Fortunately we have tools available to us that did not exist 10 years ago, that give us a fighting chance against myopia”. Being that I am a myopic optometrist and father of 7 year old twins with genetic predisposition – I am in.

1. Brien Holden, Timothy R. Frickie, David A. Wilson, Monica Jong, Kevin S Naidoo, Padmaja SanKaridurg, Tren Y. Wong Cited Ophthalmology, 2016; DOI: 10,1016 j.ophtha a.2016.01.006 Thomas J. Naduvilath, Serge Resnikoff

2. Myopa Control: A Review Walline JJ Eye Contact Lens, 2016

3. Effect of bifocal and prismatic bifocals on progression of myopia in chidren: three-year results of a randomized clinical trial Cheng D, Woo GC, Drobe B, Schmid KL JAMA Ophthamol.,2014

4. Controlling Myopia progression in children and adolescents Smith MJ, Walline JJ Adolesc. Health Med. There., 2015

5. Current approaches to myopia control Leo SW Curr. Opin. Ophthalmol., 2017

6. Five-year clinical trial on atropine for the treatment of myopia 2 Myopia Control with Atropine 0.01% Eyedrops Audrey Chia, FRANZCO, PhD, Qing-Shu Lu, PhD. Donald Tan, FRCOphth Published Online: August 11, 2015 PlumX Metrics

by Paul F. Vandiver, OD