axial length

Can Axial Length Be Reduced?

Wish I Knew Before2 Comments

Updated 4/14/22

Image credit: myopiaprofile.com (a very helpful site, btw!)

This is a niche post for those of us trying to explore the causes and cures for myopia. Since the causes of myopia are not fully understood, the treatments are still under discovery and experimentation. If you search online, you probably won’t find much evidence that the axial length of the human eye can be reduced – this is a key measurement that folks are using as an objective way to determine if axial length myopia can be reversed. However, I suspect that there exists some evidence – it just hasn’t reached Google’s top search results. I discovered that the axial length of my child’s eye was reduced over a 3 month period, leading me to think some researchers out there may have similar data on children.

So my current answer to “can the axial length of an eye be reduced?” Yes, based purely on numbers and measurements for a single child data point – more on this below, along with the caveats. All in all, it’s still encouraging information. (Update as of 11/17/22: In absence of a new post on axial length, I wanted to share that our optometrist once described a case of one teenage patient whose axial length dropped significantly for an unknown reason and the patient’s RX correspondingly dropped about 2 diopters! So YES, axial length absolutely can change, but IF and HOW it will happen is not understood.)

Here are the axial length measurements on my 8 yr old child who has an RX of OD: plano, OS: -1.25:

DateLifestyle habits leading up to the measurement dateAxial length (on Carl Zeiss IOLMaster)
Start of June 201920-20-20 near work rule, outdoor time ~1.5-2 hrs/day, “active focus” 2-3x/wk for a few minutes at a timeOD: 24.37mm
OS: 24.65mm
End of June 201920-20-20 near work rule, outdoor time ~2-3 hrs/day, “active focus” 2-3x/wk for a few minutes at a timeOD: 24.36mm
OS: 24.66mm
End of August 201920-20-20 near work rule, outdoor time ~3-4 hrs/day, “active focus” 2-3x/wk for a few minutes at a time, plus lenses when readingOD: 24.43mm
OS: 24.75mm
Beginning of Dec 201920-20-20 near work rule, outdoor time ~1.5-2 hrs/day, “active focus” 1-2x/wk for a few minutes at a time, regular wear of multifocal soft contact lensesOD: 24.38mm
OS: 24.67mm

Things to note on the data

  • In a 3 month period, there was a .05mm reduction in the right eye and a .07mm reduction in the left eye. The practitioner wasn’t surprised by the positive change and said this was known to happen with the initial wearing of multifocal soft contact lenses, from which I inferred that more reduction isn’t to be expected. 
  • .07mm is estimated to be the equivalent of 0.25 diopters, according to our optometrist.
  • .12mm is the average growth/year in the axial length of non-myopic children, according to our optometrist.
  • Although we incorporated many good vision habits, the reduction in axial length did not occur until my child was able to wear multifocal soft contact lenses. 
  • Even though the right eye is not myopic, we decided to wear multifocals in both eyes to try and help prevent the right eye from becoming myopic. After one eye becomes myopic, it is common for the other eye to become myopic as well. 
  • The increase in axial length came during the summer at a time when we were able to spend a lot of time outdoors in a lot of sunshine, we no longer had school (less near work time), and when we had added the use of plus lenses for reading. 
  • I checked my child’s vision with an eye chart a few times a week, and it seemed to me like his eyes were getting better during the 3 months that there was an increase in the axial length.
  • Our attempts at “active focus” were so few per week that it’s not a significant factor for consideration. 
  • My child gets almost zero screen time. He reads books a lot but will only occasionally read as much as 45 minute blocks which are then peppered with a 20-20-20 rule.

Thoughts on the effect of the multifocal soft contact lenses

Since I’m sitting around with my single child data point, I’m wondering if the axial length reduction is more easily induced in children. Typically the younger you are, the more likely your body is able to recover or have positive changes. I’ve noticed those patterns generally with how quickly children can recover from the same cold that knocks adults out. Similarly, oral immunotherapy on preschool age children can cure their allergies vs older children and adults are more likely to become desensitized (which is not a cure). 

Multifocal soft contact lenses were originally created for adults with presbyopia, but many adults have trouble adapting to the vision that they get with multifocals because the contact provides center distance vision and essentially places patches of plus power throughout the lens. I guess adult eyes don’t accommodate as well as children’s eyes and they tend to see both the blurry and the clear images at the same time. Children, on the other hand, are known to adapt to multifocal soft contact lenses rather easily. It would be interesting to see if adults who have progressing myopia would benefit from wearing multifocal lenses to slow or halt their myopia.

Multifocal soft contact lenses and “active focus” – Since seeing that the contact lenses seemed to make the most difference in my child’s axial length, I’ve been thinking about how they work and how it might compare to the concept of active focus which I read about on endmyopia.org. According to endmyopia, active focus is the activity you need to do to stimulate your vision to improve – you look at something that’s just very slightly blurry and then focus on it to see if you can clear the blur. When you wear multifocals, your eyes also have to do something similar on a constant basis. Because there are patches of less clear vision, your eyes have to learn to adapt to pick out the parts that are clear to create the focused image that you finally see. I could be totally off-track, but just throwing it out there. Thoughts, anyone?

If you have any axial length measurements or similar experiences, please do share! Anyway, we’ll be measuring axial length again in another few months. Stay tuned.

Resources

This is a very helpful post in providing more numbers for understanding axial length, and understanding of possible ethnic differences, and growth differences in myopic and non-myopic children:

Here are other posts that are helpful for trying to understand how practitioners use axial length in managing your child’s myopia: