Dark Days' Diaries: Can I Achieve Significant Year-Over-Year Shortening?

Since my previous outdoor time experiment gathered quite some interest, I’m going to record a similar episode for the dreaded dark season.

I’ve been trying to provide hard evidence for the Reduced Lens Method for over a year now, measuring my eyes and recording the results. Last year, I took the dark days here in the north too lightly. The bill came in the form of worsening myopia and significant elongation of both eyes, thwarting my first attempt of producing evidence just as I got my own IOL Master, which allows me to measure my eyes’ length regularly.

You can see how things unfolded since then in my all-time chart:

The top chart is refraction; note that up is better there. The bottom graphs show how the length of my eyes changed, with slow but almost continuous shortening since spring. By looking at both kinds of graphs, you can see how shorter eyes correspond to better distance vision and vice-versa.

All this means: now is a decisive time! Will my eyes worsen again, turning this into a Sisyphean back-and-forth? Or can I keep my shortened eyes until spring? Or, if I dare to wish, might it even be possible to keep improving in winter?

Overcoming this obstacle would not only give me the prospect of better vision every year, but also leave a permanent record for all the naysayers, showing beyond reasonable doubt that eyes can shorten over the long run! So, can they really?

The main changes I’m pushing, compared to last winter, are:

  • Trying to catch more outdoor daylight around noon.
  • Computer glasses reduced twice (0.5 dpt less spherical; now using -1.75 on PC at ~90cm).
  • Distance glasses roughly reduced twice (maybe a bit less due to details on glasses usage).
  • Much stronger indoor lighting has been installed.
  • Edit: outdated 2019-12-13: Trying to sleep earlier than last winter, to avoid missing daylight by sleeping in.
  • Edit: added 2019-12-13: Trying to shift computer use to earlier times in the day, to avoid excessive eyestrain after sunset.

I put this into the 20/20 Gains Updates category, since preliminary results already indicate a small year-over-year improvement, especially on my left eye. But so far, this is still based on thin data and not enough time. Over the next three months, the outcome will become a lot clearer.

At the time of this writing (2019-11-29) the darkest day of the year on average here, Christmas Eve, is now 25 days away. The period in which the elongation most likely happened last year has already started for this year, and ends in 21 days, three weeks from now. My current AL EMAs are: 25.723 mm left and 25.796 mm right – all-time record levels, as you can see in the charts.

If we turn this into a contest between mainstream optometry’s “nothing can be done” and us trickster kittehs – which of course I’m doing :stuck_out_tongue: – the data at this early point seems slightly in favor of improvement, with both eyes’ axial lengths’ moving averages below the first few samples I have from roughly one year ago. But the real decision is coming up now, with the solstice and deepest winter days ahead.

So, onward through the long nights! There will be regular updates as usual, and year-over-year comparisons of axial length will appear, with increasing precision. Feel free to comment with opinions or your experience with the dark days!


Your measurement experiments are the highlight of La Meow for me. Though there are so many other great things going on here as well, it’s great to be a member.

Too bad all us members are so spread out over the globe. What a club we would create, if we could meet weekly for measurements, stories and snacks!

Keep up the good work. I know it’s so hard for me to get outside when it’s cold, dark, and windy. And it’s so tempting to get way too much screen time while inside. I’m trying to minimize bad stimulus and maximize good stimulus myself. I had a trouble last fall and regressed also. I’m trying to avoid that this year. Time will tell.

Gotta go and brush up on my Endmyopia habits! Good luck!!


I am cautiously optimistic for you.

One thing I’ve found is that primarily indoors normalized glasses need to be weaker by about 0.25D than outside. A quarter-diopter miscorrection puts the focal plane at 4 meters, or 12 feet. If you’re indoors with walls that are typically at that distance or closer, you need to have 0.25D (or more) weaker normalized for indoors to get the same level of AF requirements as outdoors distance viewing. If you use your outdoor-optimized glasses indoors, you might not be AF-ing much at all, which becomes a problem during winter when you might not be outside all that much,

It’s this reason why I have four “active” sets of glasses, something my wife pokes fun at me for often :slight_smile: One is for driving (where I need sharpness for obvious reasons). The next is my normal “distance” glasses, with AF needed for sharp views at typical viewing distances. The next are 0.25D weaker, which I use for indoors. And finally, I have my computer glasses, which I’m aggressive about to force AF during work, as that lets me get 4-6 hours of AF in per work day.

If my theory is correct (that AF alone is enough to trigger myopia reversal, as long as the ciliary muscle isn’t used much), then you should be able to get through the winter months just fine. The trick is to always use glasses that require AF to see clearly at whatever you’re looking at.

I’ll know in a few months after the dark Pacific Northwest winter is over, if I’m right :wink:


Dark Days Diaries would have been a nice treble alliteration. I am heading for my first dark season since joining EM and am curious to find out whether my improvements will hold. In the foothills of the Pyrenees I will probably get a bit more light than in Germany.


I’m close to needing a new pair of normalized glasses, but am spending more time indoors while it snows and freezes.
How do you coordinate reductions with so many sets of lenses?

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Your data recording and datailed info are so interesting for me. Bravo!
I feel improvement are slowing down due to many unusual rainy days in a row, but today is a super sunny HD day! And my eyes get back to previous rate of improvement in few hours. It seems like my eyes were falling asleep due to darker day, thus we need to keep them awake!
20/20 at Snellen with normalized after 2h30’ bike from 12 to 14.30 with full correction + sunglasses for little little AF.

This is my first winter trying to reduce myopia.
I won’t lose any opportunity to spend time outside when is sunny, especially from 11.00 to 15.00. Skip the lunch!". Even if it’ll be freezing cold! It could be hard maybe but it’s a matter of motivation ad mental focus on the amazing process we are living.
Have a nice winter :wink:


Proposal accepted, thread renamed to Dark Days’ Diaries! :upside_down_face:

Sounds great! Just what I’m thinking, gotta use the daylight we still get!

You too, have a nice winter! :grinning:


I found I can AF in the supermarket or the mall where there’s a lot of light. I gotta try. There’s too little light to make any reductions, except for the differentials. It’s a good time to work on them using a small handheld working light.

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Well several ways :slight_smile: I’m making sure all my frames (Zenni’s other than the original sets) are distinct. I have a OneNote page where I track the diopters for each frame.

As far as managing them, it’s done empirically experimentally. In other words, I try a set, if they’re too strong/weak, I go up/down 0.25D. My criterial is if the blur is minimal, but cannot be reliably cleared with AF, then they’re just right. That’s one of the reasons I found outdoors glasses (especially in the daytime) vs indoors glasses had that 0.25D difference need.

Same with the computer glasses. I actually had to step down several steps because of the distance of my computer screen. And every few days, I’ll adjust the monitors forwards/backwards to keep at the blur edge. When I’ve pushed them too far I drop them down.

I estimate I’ll go through 20+ frames by the time I’m done (going from -4.75D to +1.25 or so in 0.25D steps). Thank goodness for cheap internet glasses! :slight_smile:


Thanks for that description. Food for thought in there.

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Man, you guys are making me glad I’m living in South Carolina.



I’m joining not doing true measurements yet but fighting by using a daylight lamp while at work.

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HAX! Grab the pitchforks! (╯°Д°)╯︵┻━┻

I can see little bits of snow on asphalt outside. The noon sun has been shining, but it’s so low, the snow doesn’t even care.


Lol, been there, done that.

This morning it’s a chilly 39 degrees Fahrenheit. We expect temps in the mid- to high-60s this afternoon.

The sun is bright and there is not a cloud in the sky. The light this morning, like last night’s sunset, was PERFECT. :smile:


It’s SO awesome that you are measuring axial length - I will be following your progress with great interest! Thank you for sharing. I wish you had higher myopia though so I could know if I’d get the same results :smiley: :smiley: :smiley:

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That’s not a nice wish haha. Plus it wouldn’t guarantee the same result for you anyway, everyone’s different :slightly_smiling_face:

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Updates and Evening Screen Time

I’m now stagnating, but at least there has not been significant worsening yet. The left eye seems to have settled around 25.72 µm, the right around 25.79 µm. My 2018 winter elongation happened around now a year ago, so while I’d prefer improvement, it’s not too bad to stay at the same level, since that could still drastically improve year-over-year improvement.

In a bit of talking with Jake, who has generously offered a closer look at my case, he offered an example schedule of daily screen time. Comparing this with mine, I noticed that my screen time is rather heavy on the evenings. Even during my outdoor experiment, computer use would often be crammed into the evening, after sunset.

Looking at various success stories that talk about screen time, the same pattern appears: in comparision, my screen use seems very heavy on the evenings. What if this is negating much of the stimulus I get at daytime? Therefore, I’m changing focus. Especially, on this point:

  • Old version: Trying to sleep earlier than last winter, to avoid missing daylight by sleeping in.

I’m not actually scrapping this point, but modifying it. This old version assumes that my main issue is with the maximum brightness I’m getting. But what if the issue is actually an inability to relax the eyes if there is too much screen time after sunset? So the point changes to:

  • New version: Trying to shift computer use to earlier times in the day, to avoid excessive eyestrain after sunset.

The idea here is that recovering from eyestrain might be much easier with daylight, and so not all screen time would be created equal. This would also explain the failure of the high outdoor vision showdown experiment: if the bottleneck was the computer use after sunset, I’ve been barking up the wrong tree by increasing stimulus well before sunset and then finishing screen work in the evening.

I’m not sure how well I’ll be able to implement this, since it’s a more radical change, but so far, I’ve been making progress. I’ve been typing this post before sunrise and went to bed around 21:00 yesterday. There was still screen time after sunset, but the duration was reduced by hours compared to typical November values.

This week has the earliest evenings of the year, so even if I should’ve hit the mark this time, it’s the hardest time to make this change work. Which is a good reason to start trying it now, since a success under winter conditions would be an extremely significant signal.


Good luck with this new strategy. I go to bed very early and wake up very early, and most of my screen work is just after I have lit my two wood stoves in the morning and had a cup of coffee - still several hours before it gets light in the winter months. But my vision is better in the morning, so maybe the screen work I do then (and not that much of it) is less harmful. I also alternate short spells of screen work with non-screen activities (the advantage of being retired) not only to rest my eyes, but also to limit sitting for too long.


To add some data point: my normal schedule is really similar to your modified. I get up at 5:20 in the morning and no prolonged screen use until about 7:00. Usually I’m in bed at 21:30 in the evening, and usually there is no screen time after about 20:30 (maybe a few minutes mobile phone, but that’s literally few minutes, not “just a few minutes” then "30 minutes later… " :slight_smile: ). I sometimes read a book somewhere between 21:00 and 22:00, but that once or twice a month. Weekend is a bit different, because getting to bed a few hours later (and waking up a few hours later), but my usual experience is that my eyes stagnate or even get worse after a weekend (regardless how much outdoor time I have), so this just points to the same direction…

About your screen setup: how well lit your surroundings when you use screen after sunset? I suspect that the usual computer / tv with no lightning or with just mood lighting is really detrimental to the eyes (unfortunately my current setup at home is close to the latter and cannot really change right now).


I was reading some of the studies done and saw that axial shortening occurred when daylight was as low as 500 lux when exposed to it for at least an hour. If you really want to hammer it, perhaps get a lux counter (they’re only around $20US) and start logging that as well. Surprisingly days that I think are really low in lux tend to be a bit higher than I thought initially. Subjective observations of brightness have been way off from what I’ve been recording on my counter objectively. I do wonder if lux are compilable for eye shortening though. For example, if it’s only 200 lux outside, can you get eye shortening with 2.5 hours for a same result of 1 hour in a day where it is 500 lux? I’m going to introduce this type of recording myself to my own experiment.