We sat down with 3 of our Coastal Vision doctors recently to discuss myopia progression in children as well as ways to reduce or control that progression.
Dr. Beach: First, Dr. Nilsson can you define myopia?
Dr. Nilsson: Myopia is the clinical term for what most people know as nearsightedness. Generally, that means near vision up close is fine but far away vision is blurry. Far away vision can mean several feet out or the television or the board at school or street signs while driving. This happens because the image is not being focused perfectly on the retina.
Dr. Beach: That brings up a good point. The image focuses on a point in front of the retina, meaning the eye is too long is some aspect. Let’s get back to that in a minute, but Dr. Tahmasian isn’t myopia on the rise?
Dr. Tahmasian: Absolutely. We’ve seen dramatic increase in people that have myopia in the U.S. The National Eye Institute has stated that 42% of the U.S. population ages 12-54 are myopic, up from 25% a few decades ago. Other studies show as much as 50% of the world population may end up having myopia within 20-30 years. The trend is very obvious and concerning.
Dr. Nilsson: And I think there’s 2 issues that are concerning. One is the higher number of children and adults that are myopic these days. But, perhaps even more importantly, it seems the severity of myopia is more progressive than before. In my clinical experience, I’ve seen more children showing rapid progression or worsening of the vision than I did earlier in my career.
Dr. Beach: I agree. 10-14 years ago I don’t recall seeing so much early onset myopia---say, like ages 6 through 10, nor as many children that seem to jump from 20/30 vision one year to 20/100 within a short number of years. Within the last 5 years, I see this scenario almost on a daily basis. Dr. Tahmasian what might be the reason for the higher myopia incidence?
Dr. Tahmasian: The number one factor to influence myopia is our genetic make up, however there are other environmental factors that drive the progression of myopia. One influencing factor is prolonged near work which can change the anatomy of the eye and can influence myopia progression. Prolonged near work includes prolonged reading, studying, computers, phones and tablet etc.. As our world of technology evolves, an increased influencing factor to cause myopia progression is that we are spending much less time outdoors being active and exploring or visually detailed world, and much more time on the screen with no breaks to rest our eyes.
Dr. Beach: And I think that brings us back to the length of the eye. These causes you mentioned are triggering the eye to elongate more than necessary and this creates poor optics for central vision. This is the worsening blurriness we see in children with progressive myopia. But now that we know that it’s elongation of the eye that is the physical change involved in myopia progression, we can use that to identify mechanisms to slow or stop that unnecessary elongation of the eye. Dr. Nilsson, you and I fit orthokeratology or CRT lenses on children and adults. How do these lenses work and are they effective at controling myopia progression?
Dr. Nilsson: Orthokeratology, or CRT lenses that we use, are hard lenses that a patient sleeps in at night. While a patient sleeps in the lenses, the cornea is gently being flattened or reshaped. CRT lenses are FDA approved for adults and children. When a patient wakes up, the lenses come out and the patient can see without glasses or contacts during the day. The process repeats every night. That’s very helpful in itself, but studies also show that CRT lenses can be an effective way to control myopia progression. Without getting too complicated, it has to do with the way the central eye is flattened but the peripheral is kept steep. This may slow down the eye from elongating which in turn decreases myopia progression.
Dr. Beach: And I think CRT lenses are a great option of treatment. Studies also show that low-dose atropine (LDA) is even more effective. The ATOM-3 study came out a year ago and that was our first 5 year study looking at how well LDA was at slowing myopia progression in children. The results were very encouraging with over 50% reduction in progression noted in the 400+ child study. To have something in once a day prescription drop form that could be so effective is a game-changer. The LAMP study came out in 2018 and confirmed these findings, although there is some debate on the best concentration of LDA. Upcoming years on the LAMP study could help us settle which concentration of medication is best. Also in the works is the CHAMP study, which is looking at medication control of myopia progression but full results may not be available until 2021. Dr. Tahmasian, why is myopia control so important?
Dr. Tahmasian: I think it’s critical for parents to understand that myopia progression in children is not just a vision issue or an economic issue (glasses/contacts). Myopia increases risks for diseases of the eye. Myopia has been studied to be a risk factor of certain ocular disorders such as retinal detachment and glaucoma which can lead to visual impairment. Because the myopic eye is longer than normal, the tissue is more stretched which puts the patient at risk for retinal holes, tears, or retinal detachment. While not every myopic patient will not go on to have a retinal detachment, the higher the myopia the greater the risk for retinal detachment. Myopia is also linked with glaucoma. Glaucoma is when there is irreversible damages to the optic nerve, which causes slow loss of nerve cells which can result in vision loss.
Dr. Beach: When should parents start to consider control methods for myopia progression?
Dr. Tahmasian: The discussion should be happening when we start to see a pattern of progression, even small amounts. That’s important because if the myopia gets too severe then certain progression control methods may be off the table.
Dr. Nilsson: Agreed. If there are consistent increases in myopia over a 3 year period then there is concern about what the future holds for that child. We need to discuss, at that point, what methods can be implemented to help slow down this path of progression.
Dr. Beach: I’d add that also age of onset is a concern. A 6 or 7 year old showing with 20/40 vision is more concerning than a 14 year old showing with that same amount. Younger onset of myopia may be a trigger to close monitoring to see if myopia progression controls are necessary.