Your little one has just drawn a blank on the eye chart’s big ‘E’.  Impossible. No way.  Can’t be, you say to yourself.  He must get a chance to try it again, as he might be confused, or shy, or being nervous.  So we try it a second time, same result,  The third attempt gets thrown out, since the subtle coaching of  “You know this letter, it comes after ‘D’ " , may have tainted the results.   Eventually we all come to an agreement, Junior may actually not see as perfect as thought.  So what do we do?  Let's list the most common options:

  1. Historically the most common option, as it's backed by rigorous folklore, is that you decline getting glasses as they will just make junior's eyes ‘dependent.’

  2. A slightly more modern take on option 1, involves requesting only half of the prescription or three-quarters, or some other round number that sounds effective, to allow the eyes to still have to ‘work’.  

  3. Get glasses for now, and take comfort in the knowledge that if Junior really despises glasses, he can eventually get contact lenses, and then after high school, refractive surgery such as Lasik.

If we fast-forward a few years, parents in all 3 scenarios are likely getting ready to get new glasses for Junior, as studies suggest that none of the options do much in slowing down the deterioration of eyesight (ironically enough, 'no glasses' may actually cause a slight increase in the progression of nearsightedness).  If all 3 options essentially lead us to the same spot (stronger glasses in the future), then it can be argued that at least option 3 allowed Junior to see the most clearly out of the three options, creating the least hindrances when it came to seeing the board at school, as well as aiding in developing proper hand-eye coordination, depth perception, and an all-around more clear vivid world.   The negative aspects of Option 3 are almost entirely related to social ramifications, as wearing glasses has historically been “un-cool”, although I would argue that has changed dramatically in the other direction, to the point of kids requesting zero-prescription so they can get glasses (but that's for another blog post).

Although getting glasses and seeing clearly is a great option, in the last few years we have found a few more methods that have actually been shown to slow the rate of myopic progression (ie the rate the prescription goes up).  These are:

4. Fit children at risk of rapidly increasing myopia with a bifocal contact lenses (yes, similar to the lenses worn by some adults that allows them to read and see far without reading glasses).  

Bifocal contact lenses have two different prescriptions in the lens, one in the periphery and one in the centre of the lens. This allows them to focus peripheral images differently than central images.

Bifocal contact lenses have two different prescriptions in the lens, one in the periphery and one in the centre of the lens. This allows them to focus peripheral images differently than central images.

5. Encourage kids to get outside and play more.  

So what's going on here? How are these options supposed to help? At its most basic level, nearsightedness can result from an eyeball simply being too long.  Front to back, from the coloured part through the pupil, and back into the head, nearsighted people typically have eyes that are longer than non-nearsighted people.  And, it turns out, that the amount and type of “peripheral blur” (ie how blurry is it in our side vision as we stare at something straight ahead) is correlated with the eye trying to elongate itself.  The mechanism of this is unclear (no pun intended), but peripheral blur seems to be the culprit.  This explains why not wearing glasses or wearing glasses has little effect on slowing the rate of myopic progression, as both options don’t address side vision clarity (option 1, 'no glasses', doesn’t address central or peripheral blur, and option 2 and 3, 'wear glasses', only addresses central vision clarity, like things we are actually looking at).  So, from this, we can see that bifocal contacts, which are designed to focus our side vision differently than our central vision, have the ability to address the side vision blur idea and that might be why they have been shown to slow the rate of myopic progression by almost 50%, which if fairly impressive.

Myopic eyes have longer axial lengths than non-myopic eyes. Measured from the cornea (the clear dome on the front of the eye) through the pupil, and back to the retina (the orange tissue lining the eyeball).

The “going outside and playing“ recommendation also address the growing eyeball problem in myopia, since studies have shown that certain wavelengths of sunlight stimulate the release of dopamine in the brain which in turn slows down the rate of growth of the eye (thankfully, the wavelengths that are useful here are the safe ones, and not the UV or harmful blue ones mentioned in my previous posts).  Interesting enough, studies are starting to suggest that the increase in smartphones, ipads and computers might not be causing the increased epidemic-like rate of myopia worldwide (with a predicated prevalence of approximately 50% in this generation of US school children), at least not in the manner we thought.  It seems that the steady decrease in outdoor time by children in the last few decades may be the culprit.  Since children should be getting outside as frequently as possible, this option really should be implemented by all parents. The bifocal contact lens option is less of a slam dunk, as fitting children with contacts is difficult, and they need to be kept clean as there is a higher risk of eye infections.

Finally, some recent studies are also suggesting that the posture we hold when we read may be another contributor.  Kids that read sitting in a chair (and looking down)  seem to end up with higher prescriptions than children that read lying on their backs and look straight ahead or slightly up at the books.  This is interesting, as it could be explained by the “side-vision blur” idea noted above, or perhaps the using of our eye muscles to look in certain directions may also play a role in the deterioration of vision.  It will be interesting to see if this study's results hold up over time.


Regardless, myopia is becoming more of an issue worldwide, and until we find a proven way to address it, we might as well work with what the studies suggest are the most effective tools and perhaps ignore some of the "old-wives" tales this time.

 

 

Dr. Burke is an optometrist practicing at Calgary Vision Centre.  Opinions above do not constitute medical advice, and readers should consult with their optometrist if they have questions or concerns about their eye health

Adler D, Millodot M. The possible effect of undercorrection on myopic progression in children. Clin Exp Optom. 2006 Sep;89(5):315-21

Effect of dual-focus soft contact lens wear on axial myopia progression in children. Anstice NS, Phillips JR Ophthalmology. 2011 Jun; 118(6):1152-61.

French AN, Ashby RS, Morgan IG, Rose KA. Time outdoors and the prevention of myopia. Exp Eye Res. 2013;114:58-68. doi: 10.1016/j.exer.2013.04.018. Epub 2013 May 2

Stewart, L. (2016, June & july). New study finds association between myopic progression and reading position. Retrieved from http://ophthalmologytimes.modernmedicine.com/ophthalmologytimes/news/new-study-finds-association-between-myopic-progression-and-reading-position?page=0,1