By Barry Santini, OD, ABOM
For more than a century and a half, a family whose child was diagnosed with needing glasses had to confront the reality—often for the first time—that life was neither perfect nor fair. Sandwiched in between a child’s reticence, a mother’s tears and a father’s quiet denial, a pair of new eyeglasses promised both an end to a blurry world and a life of dependency.
Families have long struggled to accept the vision cards they’ve been dealt because there was not much they could actually do about it. But when it comes to living with myopia, that’s all about to change. Sure, there have been various “throw your glasses away” schemes, starting with the Bates method of the 1920s, the See Clearly method of the 1990s and today’s darling of social media, Jake Steiner’s endmyopia.org. Steiner offers a free seven-part program designed to both understand the condition of myopia and reduce dependency on glasses. After all, doesn’t the old saying go, “Who really wants to wear glasses anyway?”
Going beyond the current fashion status for specs, there is now awareness of the real and tangible health threats connected with the global rising incidence of myopia. Twenty-eight percent of the U.S. population is currently diagnosed with myopia—defined as a correction of greater than -0.50 diopter—and is expected to grow to 50 percent by the year 2050, according to the Brien Holden Institute. The World Health Organization has identified the increase in myopia as the number one health threat facing vision worldwide because of its statistical association with retinal disease, anomalies and related eye conditions such as cataracts and glaucoma. So the central question regarding myopia facing eyecare professionals today is no longer solely about diagnosis, detection and correction. Rather, it is about both delaying myopic onset and reducing its rate of progression. We need to reduce the number of individuals falling into the category of high myopia category—roughly defined as over -5.50 diopters. Above all, today’s challenge is about building awareness amongst young parents that their eye doctors now possess the tools to change what older generations could not—the fate of their child’s vision.
No one is in a better position to help build awareness than the most accessible gatekeeper available to the eyewear buying public: the trained, aware and informed optician. This article serves as a primer on understanding myopia control for all opticians and ophthalmic support personnel. It is structured to see how myopic error is a hijacking of the eye’s natural process to keep vision perfectly focused during its early development, especially the school age years between 5 and 12 years old. Every child—starting no later than age 6—should be screened and assessed for their risk of developing myopia, whether the parents are nearsighted or not. Armed with this information, parents and their eye doctor can develop a proper plan to either delay the onset of myopia or reduce its rate of progression, and ensure that their children’s visual health is as free of complication and risk of potential disease as possible.
Myopia, or nearsightedness, is one of the three common refractive error conditions, along with hyperopia—farsightedness—and astigmatism, which is a two-plane optical error. In the simplest of explanations, myopia results when the eye’s refractive elements—the cornea and lens—together focus at a distance shorter than the eye’s physical axial length, resulting in an image placed in front of the retina. While almost all children are born with eyes that are far smaller than adult size, resulting in hyperopia, it is during the first 18 months or so of life that nature tries to normalize the eye’s focus by compensating for the infant eye’s too-short length by enlarging and lengthening the eye globe. Together with a reduction in the refractive power of the cornea and crystalline lens, this natural process of normalizing a young eye’s focus is called emmetropization. When this natural process is interrupted, refractive error is the result. The key here is understanding that the eye is essentially wired from birth with a robust process in place to manage the eye’s focus by lengthening the globe. The eye is naturally predisposed to signal a lengthening of its globe rather than a contraction in order to keep the best focus within a state of relaxed accommodation. This lengthening mechanism can be stimulated by many factors, including environmental ones such as close-focus activities or even a lack of outdoor activities. Most experts agree that the rising rate of myopia seen around the world and particularly in Asia cannot be explained by inherited genetics alone. Environmental factors are now seen as the prime suspects in expressing, or bringing out, an individual’s tendency toward becoming myopic.
THE MECHANICS OF MYOPIA
“Don’t sit so close to the TV. You’ll ruin your eyes!” is a parental refrain familiar to all TV-centric households, starting with my generation, the Baby Boomers. The question today is: Were our parents right? It turns out yes, but not for the reasons assumed at that time. It was thought that having the eye focus close changed the eye to remain focused close, and therefore made your nearsightedness worse. What was really happening is what we now term hyperopic peripheral defocus. Hyperopic defocus is where the peripheral retinal area, defined as starting beyond the 6 or so millimeters of the macula, either lies inside the image shell formed by the eye naturally or in conjunction with a traditional ophthalmic or contact lens. The opposite condition is referred to as peripheral myopic defocus. Here, the retina lies outside the same final image shell. And just like in telescopes, as you move outward radially from the center of the image plane, the lens area contributing to forming the image increases geometrically, not linearly. In the human eye, this is an analagous situation to the peripheral retina, which lacks the high resolution cone receptors that populate the rest of the macula, but is populated with several low resolution, light-sensing and contrast sensitive cells including bipolar, horizontal, ganglion and amacrine neuron cells. It is these non-rod-cone cells that are thought to be the engine behind the eye’s ability to determine if the object’s focus is in the highest contrast location, which is how “best-focus” is determined. In particular, the amacrine cells are thought to be sign-of-defocus sensitive, meaning they use the natural axial chromatic error of the eye to signal whether a defocus condition lies inside (myopic) or outside (hyperopic) the retinal plane.
Identifying the object image shell’s position sets off a multiple cascade of contrasting signaling events:
- If the peripheral defocus is found to be myopic in position, then choroidal-thickening events take place, which inherently resist axial elongation.
- If the peripheral defocus is found to be hyperopic, then choroidal-thinning signals are sent out, which, along with collagen/scleral-shell softening events, allow the peripheral retina to better align itself with the highest contrast image plane. This peripheral retinal “stretching” then pulls the fovea back along with it, resulting in increased axial length and an overall increase in the myopic refractive condition of the eye.
Most experts today agree that peripheral defocus is one of the most important underlying mechanisms which influences myopia, both via axial growth and the opposite force—resistance to axial growth.
THE ECONOMICS OF MYOPIA
The majority of school age children who are mildly farsighted are typically not wearing corrective eyewear because their inherently robust accommodation often masks their refractive deficiency. This is one major reason why all children should have a full eye checkup, even if no overt symptoms of abnormality are visible or are recognized by the parents.
However, most children who are nearsighted have to wear eyeglasses to correct their myopia for clear distance vision. So far, more money is being spent on eyewear and eyecare with a child diagnosed with myopia, starting from an earlier age, than hyperopia. This fact alone makes a strong case for preventing or delaying the onset of myopia and if at all possible, retarding its rate of increase as a child is immersed in their school-age years. Furthermore, there are many under-appreciated reasons for concern with being even mildly myopic. Compared to emmetropes who have normal vision, myopes can suffer from a variety of ocular problems.
At mild levels of myopia, defined as less than -3 diopters can:
- Double the risk of macula myopathy—a condition where the macula is negatively impacted, resulting in irretrievable loss of sharp vision.
- Double the risk of having a posterior sub capsular cataract, which is a clouding of part of the crystalline lens capsule.
- Triple the risk of experiencing a retinal detachment.
At moderate levels of myopia, defined as -3.00 diopters or more but less than
5 diopters, can increase the risk of retinal detachment and macular myopathy increases by over nine times.
At high levels of myopia, defined as -5.50 diopters or more, can have risks that grow to:
- A three to 10 times greater incidence of glaucoma.
- Over three times greater incidence of cataract.
- Almost nine times greater incidence of retinal detachment (>-8.00D).
- Almost 34 percent greater chance of experiencing any vision impairment.
Clearly, not only are all these increased health and vision risks desirable to avoid if left unaddressed, they’ll consume an ever greater amount of health care dollars and related resources. All in all, progressive myopia today—something past generations have taken for granted—has now been clearly defined as something that can and should be avoided.
THE EMOTIONS OF MYOPIA
Society has never been kind to eyeglass wearers. From childhood taunts of “four eyes,” “Mr. Magoo” and “nerd” to gatekeeping limits placed on military and other professional adult activities, getting through life with the stigma of deficiency signaled by having to wear nearsighted glasses is not easy. For these reasons, along with many other factors, it is easy to see the attraction of declaring, “My vision is fine. I don’t need glasses,” even when it’s not.
The same avoidance/denial of a suspected health deficiency is certainly a central element behind the reluctance of some people to go to the doctor, even when they know something is wrong with their health—essentially, they don’t want to know. And when it comes to a child’s first vision exam, avoidance/denial often causes parents to postpone or avoid this check altogether, mainly for the reason stated at the beginning of this article: They simply do not wish to condemn their child to a life of dependency on glasses, especially so early in life.
In view of this, it is easy to see the inherent appeal for various “fix-it” techniques, methods and exercises that promise to improve your vision and ultimately “throw away your glasses.” Although most of these have been reasonably discredited, it doesn’t stop people from secretly harboring the idea that wearing corrective glasses automatically makes their eyes more dependent and perhaps even permanently worse off for the wear. Addressing this “gorilla in the room” is absolutely essential to ensuring that discussions meant to improve awareness about myopia control get the required traction they deserve for both parent and patient.
OPTICAL SOLUTIONS FOR MANAGING MYOPIA
With awareness of the worldwide epidemic of myopia growing, the technical departments of many lens companies are hard at work creating new and more effective ophthalmic lens-based solutions to offer school-age children to help reduce their rate of myopic progression. Here is a short summary of the current players as of late 2018:
Carl Zeiss Vision—Their myopia-controlling lenses offer two main types (may not be available in all markets worldwide):
Zeiss Myovision—Unlike the most conventional ophthalmic lens designs that generally deliver super sharp peripheral optics through elimination of off-axis astigmatism—which places the peripheral image shell in a position of hyperopic defocus—Myovision lenses are designed to create a peripheral image shell that is in myopic defocus. Although this may result in reduced acuity off axis in some stronger Rxs, Myovision’s unique design is asymmetrical in nature, thereby allowing for both sharp central vision and acceptable peripheral acuity in the all-important 3 to 9 o’clock meridian of primary vision. This provides both the required peripheral acuity and myopia-retarding effect.
Zeiss Myokids Pro—An obvious solution to addressing the challenge of reducing accommodative lag in children is to use a multifocal-based lens. Current studies have shown that conventional progressive lenses, while attractive cosmetically, are amongst the least effective in influencing the rate of myopic progression. By using the power of digital design optimization and freeform surfacing, Myokids Pro progressive lenses have demonstrated superior comfort with reduced accommodative lag in school-age children.
Essilor—Essilor’s current entry for myopic progression control is a multifocal-based solution called Myopilux. Currently available only in the “myopia capital” of the world—Singapore, where almost 98 percent of all school age children are myopic—Myopilux lenses are designed to reduce accommodative deficiencies, aka accommodative lag, and therefore reduce pressure on hyperopic defocus.
Hoya Vision Care—Hoya offers both contact lenses as well as ophthalmic lenses for myopia control. Both are based on their DISC technology—Defocus Incorporated Soft Contact lens—derived from collaboration with the Polytechnic Institute of Hong Kong. DIMS Defocus Incorporated Multiple Segment lens—Hoya created an all new design myopia control contact lens, more effective at reducing peripheral hyperopic defocus than the traditional solution of repurposing a DV-centered lens originally designed for presbyopia. In an ophthalmic lens, such a traditional rotationally-symmetric solution does not work with an eye that moves separately behind it. By incorporating an array of mini-wavelet lenses in an ophthalmic lens offering, Hoya is able to ensure that any image point subtended by the gaze of the eye would be clear and have acceptable contrast sensitivity, while simultaneously providing a peripheral myopic defocus to reduce stimulating axial growth.
SightGlass Vision—Compared to traditional peripherally well-corrected ophthalmic lenses, SightGlass lenses feature a slightly diffusive transmittance character that reduces the high signal difference between adjacent cones to reduce peripheral hyperopic defocus. In addition, SightGlass posits its inherently diffusive character distributes less light behind the retinal plane and that its benefits are not compromised even if accommodative lag is present.
BUILDING MYOPIA CONTROL AWARENESS
Because most opticians see their clients without an appointment and do not require a co-pay at time of visit, naturally they are by far the most frequent consumer contact point for all things eye-related within the brick-and-mortar universe. In light of this, opticians today have a Grade A responsibility to keep abreast of all the developments, technology and contemporary solutions available for any of their client’s optical needs. And with the rapid pace of advancements today, this will increasingly include knowledge of and willingness to adopt solutions to vision issues such as myopia progression control that ultimately will impact their livelihood from prescription lens replacements. But as they say, the best defense is often a good offense, and embracing the technology and promise of myopia progression control may yet be the best way for main street opticals to rebuild and re-establish the trusting relationship so completely essential for surviving and thriving in today’s volatile optical marketplace.
At the same time, the fact that many consumers are managing their vision deficiency through an online interaction—whether by purchasing glasses and contacts, or interacting with a real doctor through the technology of telemedicine—offers undeniable proof that convenience can largely mitigate most negative aspects of being nearsighted. All, perhaps, save the increased eye health risks only now becoming fully appreciated.
The responsibility for having this conversation starts as the optician sits down daily to assist a family with young school-age children with a legacy of family myopia. And even if you decide to go “all in” on managing myopia, always be cognizant that implied promises often lead to expectations that can backfire in disappointment. As with all things vision, be sure to communicate that although your mileage can and will vary—that’s certainly no reason not to try. With only a modest effort, giving hope that a child’s refractive destiny is no longer out of their control will be thrilling news to each and every parent, especially those who themselves have worn eyeglasses.
The world of interesting facts about myopia is large—far too large to do full justice here. Instead, let’s take a short dive into some interesting tidbits about myopia.
When you successfully persuade a parent to explore myopia control for their child, the next question will inevitably be, “Where do we begin?” At this point, if your office is not offering myopia control, you should have a list of local practices who specialize in it available as a handout. You should also point parents to online sites, such as treehouseeyes.com and myopiacontrol.org, where they can become acquainted with the myopia control community and understand the fundamentals as well as the risk assessment process. There are currently two main assessment metrics applied to approximately seven contributing factors:
- WHAT IS THE RISK OF BECOMING NEARSIGHTED? The younger a child becomes nearsighted, the greater the total amplitude of adult-age myopia.
- WHAT IS THE RISK OF EXPERIENCING A FAST MYOPIC PROGRESSION? Defined as greater than -0.75D change per year, a high risk of fast myopic progression will further contribute to the total amount of adult age myopia realized.
The fundamental myopia control strategies are therefore two part in nature: First, try to put off or delay the onset of myopia. Second, reduce the rate of myopic progression as much as possible. Because the eye globe is still in growth mode during the school age years between 6 and 11, doctors normally see an acceptable rate of myopic progression of 0.25D per year as normal.
Here are the common factors evaluated in a myopia control risk assessment:
AGE—The younger a child is, starting around age 6, the greater the risk of developing myopia or experiencing a fast rate of myopic progression.
FAMILIAL LINK—Having one or both parents nearsighted increases the risk that their children will become nearsighted by two and a half to six times, and the risk of experiencing a fast rate of progression may increase up to three times. Ethnicity—Asian children may experience over a 0.50D per year greater rate of fast myopic progression compared to children from European backgrounds.
REFRACTIVE ERROR—Since a child’s eye does not fully reach adult size until approximately age 10, there is a table of the expected amount of latent hyperopia to be assessed at each year until age 10. This can only be assessed through a complete cyclopedic—aka accommodation relaxing—exam. For example, at age 6, a normal child is expected to demonstrate +1.25D of hyperopia. If the amount found is say +0.75D, this is a marker of concern that this child is predisposed to becoming myopic.
ACCOMMODATIVE LAG—This is defined as the difference between the full dioptric value needed to perfectly focus on a near-located object, and the actual dioptric value found in the child’s eyes during testing. Its significance lies in the fact that lack of full close focus further places the eye into a greater state of hyperopic defocus, which is a known trigger for axial elongation and subsequent myopic progression.
TIME SPENT ON NEAR WORK—With the time spent during school age years on reading and today, interacting with computers, phones, tablets and games, the daily hours recorded for near work is an important precipitant toward placing the eye in a state of hyperopic defocus. Indoor environments are rich in an array of different defocus stimulants.
TIME SPENT OUTDOORS—Aside from the fact that time spent outdoors usually means less time spent focusing on near objects, there are myopia-onset delaying factors associated with exposure to sunlight including increased dopamine and Vitamin D production and scleral shell strengthening. Of course, if your kids are outside, they’re probably not spending time on tablets, phones and games.
It’s not beyond the realm of possibility to imagine children eventually receiving a state-funded mandate to not only have a complete eye exam before they begin grade school, but also include a myopia risk assessment based on the above factors.