For the child myopia book I’m revisiting hundreds of the more relevant studies on the subject, looking to pick out some of the better ones to help parents understand the full picture of myopia.
It turns out that there are plenty that have considered the negative impact of minus lens use for close-up, and looked into smarter alternatives to “minus for everything”.
Here is one, as example:
“To examine baseline measurements of accommodative lag, phoria, reading distance, amount of near work, and level of myopia as risk factors for progression of myopia and their interaction with treatment over 3 years, in children enrolled in the Correction of Myopia Evaluation Trial (COMET).
COMET enrolled 469 ethnically diverse children (ages, 6-11 years) with myopia between -1.25 and -4.50 D. They were randomly assigned to either progressive addition lenses (PALs) with a +2.00 addition (n = 235) or single vision lenses (SVLs; n = 234), the conventional spectacle treatment, and were observed for 3 years. The primary outcome measure was progression of myopia by autorefraction after cycloplegia with 2 drops of 1% tropicamide. Other measurements included accommodative response (by an open field of view autorefractor), phoria (by cover test), reading distance, and hours of near work. Independent and interaction analyses were based on the mean of the two eyes. Results were adjusted for important covariates with multiple linear regression.
Children with larger accommodative lags (>0.43 D for a 33 cm target) wearing SVLs had the most progression at 3 years. PALs were effective in slowing progression in these children, with statistically significant 3-year treatment effects (mean +/- SE) for those with larger lags in combination with near esophoria (PAL – SVL progression = -1.08 D –
The results support the COMET rationale (i.e., a role for retinal defocus in myopia progression). In clinical practice in the United States children with large lags of accommodation and near esophoria often are prescribed PALs or bifocals to improve visual performance. Results of this study suggest that such children, if myopic, may have an additional benefit of slowed progression of myopia.”
Of course these aren’t specialists that deal with only myopia reversal on a day to day basis. They aren’t employing some of the aspects that are key to stopping myopia (active focus, primarily). Subtracting two diopters from the minus for close-up is going to change stimulus a lot, and certainly create less myopia. But you do have to use the lens if you want more than just less of the problem. You need to actively use the lens to work for better vision, to get more positive benefits.
And of course the really interesting thing is that this strategy works for everyone, you don’t need to find yourself having large lag in accommodation or near esophoria. Just don’t go for a whole lot of minus lens for your close-up work, and you won’t totally mess up your eyes.
There are also other issues that we discuss here from time to time. For example the fact that it’s quite easy to cheat with progressive lenses, and simply not look through the bottom part of the lens. If you combine the fact that the top half of the lens is much easier to see through and the lack of active focus efforts, positive results diminish greatly.
But still, even with studies that get most of it wrong, there is still statistical relevance to the basics of stimulus and the dynamic eye. They are an interesting read, anytime the premise is “what if we just use a little less of all this corrective lens business”?
No shortage of these studies, even if they throw in a lot of “CYA”. Here, in OPO there is one, titled “The effectiveness of progressive addition lenses on the progression of myopia in Chinese children”:
“Purpose: To evaluate the effectiveness of progressive addition lenses (PALs), with a near addition of +1.50 D, on the progression of myopia in Chinese children.
Methods: We enrolled 178 Chinese juvenile-onset acquired myopes (aged 7–13 years, −0.50 to −3.00 D spherical refractive error), who did not have moderately or highly myopic parents, for a 2-year prospective study. They were randomly assigned to the PAL group or single vision (SV) group. Primary measurements, which included myopia progression and ocular biometry, were performed every 6 months. Treatment effect was adjusted for important covariates, by using a multiple linear regression model.
Results: One hundred and forty-nine subjects (75 in SV and 74 in PAL) completed the 2-year study. The myopia progression (mean ± S.D.) in the SV and PAL groups was −1.50 ± 0.67 and −1.24 ± 0.56 D, respectively. This difference of 0.26 D over 2 years was statistically significant (p = 0.01). The lens type (p = 0.02) and baseline spherical equivalent refraction (p = 0.05) were significant contributing factors to myopia progression. Mean increase in the depth of vitreous chamber was 0.70 ± 0.40 and 0.59 ± 0.24 mm, respectively. This difference of 0.11 mm was statistically significant (p = 0.04). Age (p < 0.01) was the only contributing factor to the elongation of vitreous chamber. Different near phoria (p < 0.01) and gender (p = 0.02) caused different treatment effects when wearing SV lenses. However, there were no factors found to influence the treatment effect of wearing PALs.
Conclusions: Compared with SV lenses, myopia progression was found to be retarded by PALs to some extent in Chinese children without moderately or highly myopic parents, especially for subjects with near esophoria or females.
You might be tempted and sarcastically ask, why would not wearing single vision lenses for everything only benefit high risk myopes? If they are better for those who are at significant risk of developing myopia, how would they possibly not be better for everyone else, the regular myopes?
Nonetheless, at least even with trying not to be too obvious in pointing at the fallacies of mainstream fandom of just prescribing everything to the maximum, there is an enjoyable amount of hints in science towards healthy eyeballs.
Less blanketing your life with minus, better longterm vision health.
I hope you are already enjoying the benefits of working your way out of the prescription racket!