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Benefits of myopia control outweigh risks
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LAS VEGAS – Slowing the progression of myopia can reduce the risk of other ocular pathology, with these benefits outweighing the risks of contact lens wear or atropine use, Mark A. Bullimore, MCOptom, PhD, FAAO, said during the Global Contact Lens Forum here at Vision Expo West.
Specifically, controlling myopia progression by 1 D reduces the risk of myopic maculopathy by 40%, the risk of open-angle glaucoma by 20% and the risk of visual impairment by 20% and saves between 0.5 and 1 year of visual impairment, he said.
Orthokeratology (ortho-K) has been practiced for many years, Bullimore said, and multiple studies have shown that wearing ortho-K lenses for 2 years can slow axial elongation by 0.25 mm.
“Atropine is being prescribed all over the world,” he said. “The dose of choice is 0.01%, but that’s ineffective. The Low-concentration Atropine for Myopia Progression (LAMP) study (Yam et al.) showed that it slowed refractive error progression slightly, but did not slow axial elongation. The 0.05% dose was found to work.”
CooperVision has developed a soft contact lens not yet available in the U.S., Bullimore said.
“They’ve published 3-year randomized clinical trial results [Chamberlain et al.] that clearly demonstrate that this daily disposable soft contact lens has the potential to slow myopia by 0.32 mm over 3 years – about 0.75 D over 3 years,” he said. “The results are quite compelling.”
A range of myopia control options are available now and more “will be coming down the pike.” Bullimore said.
Last year, Hong Kong Polytechnic University announced that it developed a spectacle lens that slowed myopia progression by 60% and halted progression in 21.5% of Chinese children in a randomized controlled trial. Principal investigator Carly Lam, BSc (Hons), MSc, PhD, told Primary Care Optometry News in a previous interview that the university is collaborating with the Hoya Corp. to commercialize the Defocus Incorporated Multiple Segments Spectacle Lens.
“The nice thing about these data is there’s good agreement between effect on refractive error and the axial elongation,” Bullimore said in his presentation. “Axial elongation is what we are concerned about. People lose vision because their eyes have grown too long.”
At the recent International Myopia Conference in Tokyo, Essilor announced its design for a myopia control spectacle lens, Bullimore said.
“You have a lot of corporate power coming into the field, and they will not only talk to you, but they will talk to your patients,” he said.
Adenosine receptor antagonists are next as one of the most promising treatments, he added.
“Headlines say half the world will be myopic by 2050,” Bullimore said. “But it’s not just about the nature of the public health problem; it’s about the patient in my chair. A myopic mother may ask how much her child will progress and what her risk of eye disease is. And if we put kids in contact lenses and use atropine, what’s the risk?”
Stapleton and colleagues reported on the incidence of contact lens-related microbial keratitis in Australia and showed that the risk is small.
“The safest modality is daily wear, regular overnight wear increases risk, and sleeping in contact lenses on a regular basis increases the risk of microbial keratitis,” Bullimore said. “But not all microbial keratitis leads to vision loss. They found 15% of all microbial keratitis cases (285) led to at least two lines of vision loss. Other studies out of the U.K. and Europe show lower numbers.
“It doesn’t apply to myopia control, doesn’t talk about ortho-K and doesn’t talk about children,” he added.
Bullimore’s own paper published in 2017 showed that children are safer wearing soft contact lenses than adults.
The Contact Lens Assessment in Youth Study (Chalmers et al.) evaluated corneal infiltrative events and showed that 8- to 12-year-olds, “the kids we would be putting in lenses for myopia control,” Bullimore said, are the safest.
“There is an increase in incidence when they turn into teenagers and even higher in college years,” he said. “Then it returns to a lower level in the 20s and 30s. This tells us that the younger kids seem to be safe, probably because they listen to their parents.
“Prospective studies are looking at lenses for myopia control,” he continued, “and authors forget to tell us about how safe the lenses are.”
Bullimore said when ortho-K first came out, there were reports of infections, such as Pseudomonas and Acanthamoeba, and they occurred primarily in children.
“But we didn’t know what lenses patients were wearing, how they were taking care of them and, most importantly, we didn’t know how many kids were actually exposed to this risk,” he said.
Bullimore and colleagues evaluated more than 1,000 patients, half adults and half children, in a randomized, prospective clinical trial involving 2,600 patient years.
“Within that population we had 50 reports of painful red eye, of which eight presented with corneal infiltrates, and two were classified as microbial keratitis by an independent panel,” he said. The risk was 7.7 per 10,000 patient years.
“Both were in kids, so the risk in kids is 14 per 10,000 patient years,” he said.
“Taking this back to the overall risk of lens wear in children, we can put it in context and decide that level of risk is acceptable,” he said. “If we have a daily disposable lens for kids, we can minimize the incidence of problems.”
Bullimore said he and Noel A. Brennan, MScOptom, PhD, FAAO, recently published a paper that outlined three broad benefits of “lowering a young patient’s ultimate level of myopia: better vision when uncorrected and corrected; better options for, and outcomes from, surgical myopia correction; and reduced risk of blindness associated with higher levels of myopia.”
This third item is most concerning, he said. “The big ‘baddie’ here is myopic maculopathy.”
He said that this paper showed that “every diopter of myopia increases the risk for frequency of myopic maculopathy by 67%. In myopia control, every diopter we can prevent lowers the frequency by 40%.”
Bullimore concluded: “It’s my belief that the scales firmly tip in the benefit direction. If we worry about contact lenses in children ... if we choose a safe modality, the benefits far outweigh the risks.
“The time is now to think about this and find your voice with your patients and incorporate it into your practice,” he added. “Your patients will start knocking on your door asking about it.” – by Nancy Hemphill, ELS, FAAO
References:
Bullimore MA. Optom Vis Sci. 2017;doi:10.1097/OPX.0000000000001078.
Bullimore MA, et al. Optom Vis Sci. 2013;doi:10.1097/OPX.0b013e31829cac92.
Bullimore MA, et al. Optom Vis Sci. 2019;doi:10.1097/OPX.0000000000001367.
Chalmers RL, et al. Invest Ophthalmol Vis Sci. 2011;doi:10.1167/iovs.10-7018.
Chamberlain P, et al. Optom Vis Sci. 2019;doi:10.1097/OPX.0000000000001410.
Stapleton F, et al. Ophthalmology. 2008;doi:10.1016/j.ophtha.2008.04.002.
Yam JC, et al. Ophthalmology. 2019;doi:10.1016/j.ophtha.2018.05.029.
Disclosure: Bullimore reports he is a consultant or speaker for Alcon, CooperVision, Essilor of America, Eyenovia, Genentech, JCyte, Johnson & Johnson Vision, Novartis, Paragon Vision Sciences and Tearfilm Innovations. He reports he has ownership in Ridgevue Publishing, Ridgevue Technologies and Ridgevue Vision.