Therapeutic pyramid guides treatment of progressive myopia
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In 1980, while helping the late George O. Waring III prepare the grant application for the soon to be initiated Prospective Evaluation of Radial Keratotomy study, I reviewed the world literature on the incidence and prevalence of myopia.
At that time, in the United States, approximately 25% of the population was myopic, 25% hyperopic and 50% emmetropic within ±0.5 D of plano, while 30% had 1 D or more of astigmatism. I was amazed to learn that in some Asian countries as much as 50% of the population manifested myopia. Today, 4 decades later, the prevalence of myopia in the U.S. has increased from 25% to near 45%, and in some Asian countries, myopia is approaching 90%.
There are approximately 30 million children in the U.S. today with some level of progressive myopia, and another 1 million join them every year. While there are several theories as to the cause, and this extraordinary increase in myopia is likely multifactorial, most authorities believe a major factor is the increasing near demands placed on children during the developmental years. In today’s digital world, many of our youth spend 12 or more hours a day focused at near on printed material, a cell phone, a tablet or a computer.
One might ask, does progressive myopia demand treatment? After all, it is only a refractive error and can be corrected with glasses, contact lenses or even surgery. Evidence supports the position that just like glaucoma, in which every millimeter of elevated IOP matters, in myopia, every diopter of progression is important and increases the risk for sight threatening comorbidities.
The most common comorbidities are cataract, glaucoma, retinal detachment and, the most feared of all, myopic maculopathy. Even with mild myopia of –2 D, the risk for cataract is increased two times, glaucoma four times, retinal detachment three times and myopic maculopathy two times. For the moderate myope between –2 D to –6 D, cataract risk increases three times, glaucoma four times, retinal detachment nine times and myopic maculopathy 10 times. From –6 D to –9 D, cataract risk increases five times, glaucoma 14 times, retinal detachment 22 times and myopic maculopathy 41 times. For more than –9 D, retinal detachment risk is a frightening 44 times greater and myopic maculopathy 348 times greater than that experienced by an emmetropic or hyperopic patient. Every diopter in progressive myopia matters.
The base of the therapeutic pyramid in treating progressive myopia is behavioral modification. One to 2 hours of outdoor play per day is therapeutic, perhaps from the switch from near to distance viewing and perhaps from increased exposure to more violet and blue light. In addition, following the 20-20-20 rule, in which after every 20 minutes of near demand distance gazing at an object 20 or more feet away is performed for 20 seconds minimum, is recommended. For this goal to be achieved, it is best to put a child’s study and computer desk in front of a window rather than in front of a wall. During these rest periods, frequent blinking can also help circumvent digital eye strain symptoms caused by reduced blink rate-induced evaporative dry eye.
The next level of therapy is optical. The ideal optical therapy remains controversial and requires further study, but all agree full correction of the distance refraction with frequent upgrades to new fully corrected glasses is preferred. This means the child with progressive myopia must be under the care of an eye care provider with interest and knowledge regarding progressive myopia. Some clinicians favor single vision glasses or contact lenses, some bifocal or progressive glasses or contact lenses, some orthokeratology, and more specialty glasses and contact lenses specifically designed for the management of progressive myopia are becoming available every year. While optical recommendations vary, appropriate monitoring and optical correction of the progressive myope with regular prescription upgrades are critical.
The third adjunct for treatment is the pharmacologic therapy of progressive myopia. My first introduction to this mode of treatment was the use of 1% atropine sulfate drops in the 1970s by John Dyer, MD, a prominent pediatric ophthalmologist at the Mayo Clinic. The side effects were significant, and many patients became intolerant, but efficacy was apparent in reducing the rate of myopia progression. The important studies from the Singapore National Eye Centre by Donald Tan, MD, and colleagues have shown that lower concentrations of atropine eye drops are also effective. Most leaders in the field utilize concentrations between 0.01% to 0.1%.
Today, there is no FDA-approved and labeled eye drop to treat progressive myopia, so current therapy requires the use of atropine drops prepared on prescription by a specialty compounding pharmacy. I am advised by reliable sources that well more than 1 million prescriptions of low-dose atropine drops have been filled in America from these specialty compounding pharmacies. Several companies around the globe are engaged in well-designed clinical trials seeking regulatory approval. In the U.S., the interested reader can look at the websites of Eyenovia, Ocumension Therapeutics, Sydnexis and Vyluma.
I believe it will be important to capture all young myopes at age 4 to 5 years in an eye care provider’s office and treat them appropriately until their myopia stabilizes, which can be as late as the middle 20s in age. Every year we will learn more, as this therapeutic area is attracting significant human and financial capital because the total addressable market in progressive myopia is extremely large. The amazing innovation cycle is in the process of working its magic for the progressive myope.
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