Address myopia early to avoid problems later
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Myopia, which affects more than 1 billion people worldwide, has become a major global vision concern, and the problem is only getting worse.
In 2015, a study published in Community Eye Health Journal reported that 27% of the world’s population was affected by at least 0.5 D of myopia and suggested that the number of people with myopia was expected to rise in absolute numbers as well as the percentage of the population. Among some populations in Asia, the prevalence of myopia was already as high as 97% in late teenagers and young adults in 2010.
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“These children can’t see when they’re in school, and they’re squinting when they’re playing sports,” OSN Pediatrics/Strabismus Section Editor Robert S. Gold, MD, said. “It’s really important to catch this early. General pediatricians should be screening these kids starting in the first year or two of life.”
Not only is the problem becoming more widespread, but it is also becoming more severe. The prevalence of moderate myopia, ranging between –2 D and –7.9 D, increased from 11.4% in 1972 to more than 22% in 2004. Over the same time period, the prevalence of high myopia, defined as more than –8 D, increased from 0.2% to 1.6%. In 2010, the global prevalence of myopia of at least 5 D was 2.9%.
While myopia’s effect on vision is clear, its impact goes beyond a simple refractive error. OSN Refractive Surgery Board Member Vance Thompson, MD, said his practice and others are full of adults with myopia that was never addressed when they were younger.
“Ophthalmology is seeing a lot of patients with refractive error,” he said. “Would they still be a candidate for corneal refractive surgery if they had been treated when they were younger? What would their refractive error be? When I see patients with retinal complications or glaucoma, I think about where they would be if they would have had myopia management in their childhood.”
Anatomical changes
Myopia can lead to more serious eye conditions later in life because of how it changes the actual shape of the eye. Thompson said myopia forces anatomical changes to the eye, with axial length elongating at a faster rate. Axial myopia can have lasting ramifications for patients later in life.
“These are patients who are at higher risk for retinal tears and retinal detachments,” Nandini Venkateswaran, MD, said. “We’re always counseling them on the warning signs of flashing lights, floaters or a curtain over their vision. We should be monitoring them carefully for any retinal pathology.”
According to a systematic review comprising more than 48,000 people published in Ophthalmology in 2011, the pooled odds ratio of the association between myopia and glaucoma based on a set of 11 risk estimates was 1.92 (95% CI, 1.54-2.38).
In a 2002 analysis of the Blue Mountains Eye Study, there was an association between high myopia of –6 D or less and incident nuclear cataract (OR = 3.3; 95% CI, 1.5-7.4). Additionally, incident posterior subcapsular cataract was associated with any myopia (OR = 2.1; 95% CI, 1-4.8), moderate myopia of –3.5 D or less (OR = 4.4; 95% CI, 1.7-11.5), and use of distance glasses before the age of 20 years (OR = 3; 95% CI, 1-9.3).
The link between myopia and retinal detachment is well known. As the severity of myopia goes up, so does the risk for detachment. Patients with high myopia are at least five times more likely to experience retinal detachment.
“Some really high myopes can develop pathologic myopia and have permanent retinal changes that preclude them from achieving 20/20 vision,” Venkateswaran said. “Sometimes patients with high myopia can also have corneal ectasia.”
To prevent some of these long-term issues, myopia must be controlled and not allowed to progress, so it should be addressed in childhood, Thompson said.
“They can get surgery to correct their refractive error, or they can do some things to lessen their myopia, but it’s not going to affect the rate of eye growth,” he said. “We need to catch them in their preteen and teen years.”
To accurately measure myopia progression, Thompson said a patient’s eye care team can use devices typically used for IOL calculation and refractive surgery, such as the IOLMaster (Zeiss) or an A-scan device, to get the patient’s precise axial length, revealing the degree of myopia.
“We know that a 0.1 mm change in axial length equates to about 0.25 D of increased myopia,” he said. “Slowing the growth of axial length allows us to make a big difference in our patients’ lives.”
According to a study published in Optometry and Vision Science in 2019, slowing myopia by 1 D should reduce a patient’s likelihood of developing myopic maculopathy by about 40%. Additionally, slowing myopia should improve the risk for maculopathy whether the patient has high or low myopia.
Slowing progression
Screening children for myopia starts early in most cases. Gold said many schools have mass screening programs that begin in kindergarten or first grade.
“Not every child needs a comprehensive eye exam,” he said. “Understanding their family history and those school screenings should be enough.”
If problems are not identified early, sometimes it is not possible to correct the child’s vision to where it should be at 20/20, otherwise known as refractive amblyopia, Gold said. As the patient gets older, the myopia starts to progress and gets worse.
When children need treatment for myopia, the most conservative and common method is corrective lenses, along with more time outside, Gold said. During the pandemic, myopia became even more of a problem because children were not out in the sun as much as normal.
“Being outside and exposed to the sun actually will help decrease the amount of myopia,” he said. “During the pandemic, kids were stuck inside, so myopia went crazy, and kids worsened even more rapidly.”
However, as these children grow, so will their eyes, and therefore, their myopia will progress naturally.
“Everybody has different thresholds for how they treat this,” Gold said. “Most kids will progress about 0.5 D to 1 D of myopia per year until they stop growing.”
When the progression reaches a concerning point, Gold said pharmacologic treatments become an option, starting with low-dose atropine.
The efficacy and optimal concentration of atropine were evaluated in a study published in Ophthalmology in 2019. The study comprised 438 children between the ages of 4 and 12 years with myopia of at least –1 D and astigmatism of –2.5 D or less. Participants were randomly assigned 1:1:1:1 to receive 0.05% atropine, 0.025% atropine, 0.01% atropine or placebo nightly for 1 year.
After 1 year of treatment, the mean change in spherical equivalent was –0.27 D in the 0.05% group, –0.46 D in the 0.025% group, –0.59 D in the 0.01% group and –0.81 in the placebo group (P < .001). The mean increase in axial length was 0.2 mm, 0.29 mm, 0.36 mm and 0.41 mm, respectively (P < .001). All three concentrations of atropine were well tolerated and had no adverse effect on vision-related quality of life.
“Right now, most people are starting with 0.01% of atropine and using it every night,” Gold said. “The problem I find with that is it is something that has to be used for many years based on when you start it.”
There is a lot of variability on how physicians use atropine to treat myopia, Gold said. Some will try it for as long as 3 years, while others will increase the dose to 0.025% or 0.05% if they are not seeing slowed progression by 6 months.
“The side effects are minimal even at those doses,” Gold said. “It doesn’t dilate pupils much. It doesn’t give them light sensitivity or blurriness.”
Gold said he starts a discussion with the family about atropine as early as age 6 years. After an initial visit, he will bring patients back 6 months later to check for progression.
“If the parents are very proactive and want to start drops, I’ll do that,” he said. “But I warn them that this is something that they’re going to have to do for many years, some for 5 to 7 years or more.”
Beyond pharmacologic therapy, physicians also have the option of contact lenses that help slow progression of myopia. In Gold’s practice, he uses MiSight (Cooper- Vision).
“It’s a soft lens that has a series of concentric rings, almost like a bifocal contact lens, that they call peripheral defocusing,” Gold said. “It seems to work nicely in slowing progression. Again, it’s variable and doesn’t work on every patient. You have to have a child that’s willing to wear contact lenses, which usually doesn’t happen until they’re around 10 years old.”
The MiSight lens was evaluated in a randomized controlled trial published in Optometry and Vision Science in 2019. The trial included 109 children between the ages of 8 and 12 years with no contact lens history and a spherical equivalent refraction of –0.75 D to –4 D.
In the group that received MiSight, the unadjusted change in spherical equivalent refraction was –0.73 D less than in the control group (P < .001). The mean change in axial length was also lower in the MiSight group (0.3 mm) compared with the control group (0.62 mm; P < .001).
“It’s just like fitting someone with a contact lens,” Gold said. “It just has different parameters.”
Even with these treatments, along with others such as orthokeratology, Gold said management of myopia is continually evolving.
“Every pediatric eye specialist has to feel comfortable with their own protocols,” he said. “There are some who are more old school and like to let nature take its course. I don’t think any of the treatments are wrong. You just have to individualize every patient.”
Adult correction
While progression of myopia ends around the time a person stops growing, they still have to deal with the visual impediments of their refractive error. Ophthalmologists have a number of refractive and laser vision surgical options to address these errors in adults.
OSN Associate Medical Editor William B. Trattler, MD, said it is important that patients get some kind of myopia management once myopia is diagnosed in childhood to reduce their risks for more serious complications from high levels of myopia, as well as set themselves up for better results with vision correction procedures later in life.
“If we can stop myopia from progressing to the –8 D to –15 D range and keep it in the –2 D to –4 D range, we will be able to provide much better results with laser vision correction, ICLs and our other vision correction procedures,” he said.
Trattler sees patients with myopia between the ages of 18 and 45 years in consultation for refractive surgery. Correcting their myopia comes down to finding the right fit with the various surgical procedures. Luckily, technology and techniques have advanced to a point where a large majority of patients are candidates for surgical correction, he said.
“I’d say that 90% of myopic patients who come in for consultations can potentially be candidates for refractive surgery,” Trattler said. “There’s a small group of myopic patients who have conditions such as severe dry eye, keratoconus or poorly controlled autoimmune conditions that disqualify them from LASIK and potentially PRK. But for the most part, most patients who are seen for consultations are often eligible for some type of refractive procedure.”
The four main procedures used in adult myopia are LASIK, PRK, SMILE and the EVO ICL (STAAR Surgical).
“Of course, if you ask surgeons about their preferred surgical method, they may each give different answers. ICL is my first choice for my myopic patients who have a prescription of –3 D or higher,” Trattler said. “I’ve just been very impressed with the patient experience with the EVO ICL, as it provides very high-definition vision and fast visual recovery. From a surgical standpoint, the procedure is very straightforward with a rapid learning curve, and with proper technique, there is a low risk for intraoperative complications.”
Venkateswaran said many factors come into play when trying to figure out the ideal treatment, including patient age, degree of myopia and vision goals.
“Many of us would consider corneal refractive surgery for a mild to moderate myope who has an otherwise healthy ocular exam,” she said. “But when you start to venture into degrees of higher myopia, you will want to consider ICL or lens-based surgery.”
Communication
With all of the issues that can occur if myopia is not addressed earlier in life, Thompson thinks the eye care community should take advantage of its unique position to spread awareness.
“It may be too late for the adult patients I see in my practice, but it’s not too late for their children or their grandchildren,” he said. “I like to educate my patients on myopia management because I know they all envision a brighter future for their children. In particular, patients with refractive error are often trying to figure out how to minimize that negative effect in their child’s life.”
Thompson said people are often surprised to learn about the options to control myopia in childhood, as well as the potential for severe ocular pathology that myopia can cause later in life.
“We’re seeing these patients in our office and sort of have a captive audience,” he said. “Educating these parents and grandparents is a super powerful way to get the word out that there are options to help these kids.”
As a refractive surgeon, Venkateswaran said she became aware of the importance of myopia control by seeing the sheer number of patients with high prescriptions presenting to her for vision correction evaluations. The debilitating nature of myopia was not something she appreciated until she started seeing these patients and performing their refractive surgeries, she said.
“Patients cannot often function and do not live normal lives without their glasses or contact lens correction. If there are methodologies that we can start to implement in childhood that can slow or even arrest the progression of myopia, I think we’re doing an amazing service to our population,” she said. “It may limit our patient pool to a degree as refractive surgeons, but I certainly want to reduce the number of patients walking around with high refractive error.”
- References:
- Bullimore MA, et al. Optom Vis Sci. 2019;doi:10.1097/OPX.0000000000001367.
- Chamberlain P, et al. Optom Vis Sci. 2019;doi:10.1097/OPX.0000000000001410.
- Holden BA, et al. Community Eye Health. 2015;28(90):35
- Marcus MW, et al. Ophthalmology. 2011;doi:10.1016/j.ophtha.2011.03.012.
- Yam JC, et al. Ophthalmology. 2019;doi:10.1016/j.ophtha.2018.05.029.
- Younan C, et al. Invest Ophthalmol Vis Sci. 2002;43(12):3625-3632.
- For more information:
- Robert S. Gold, MD, of Eye Physicians of Central Florida, can be reached at rsgeye@gmail.com.
- Vance Thompson, MD, of Vance Thompson Vision in Sioux Falls, South Dakota, can be reached at vance.thompson@vancethompsonvision.com.
- William B. Trattler, MD, of Center for Excellence in Eye Care in Miami, can be reached at wtrattler@gmail.com.
- Nandini Venkateswaran, MD, of Massachusetts Eye and Ear Waltham, can be reached at nandini.venkat89@gmail.com.
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