In the last two weeks or so, I had the biggest drop in focus distance (centimeters to blur on the computer) since I began logging last spring:
Image: my log, in diopters relative to the horizon. The green dots are calculated from my focus distance to my computer screen, with about 1 dpt undercorrection. Light blue dots are from autorefractors, orange are manual tests by optometrists (with cylinder ignored).
Because of the lack of progress since September, I’ve been troubleshooting before the drop began, doing a few tweaks on my computer and reading setup. But I find it hard to believe that this drop was caused by a few small changes. Brightness when measuring doesn’t seem to be the cause either. And I don’t think I’m doing anything that could cause this much ciliary muscle spasm. So either my eyes are rapidly worsening for unknown reasons, or there’s some other factor involved.
So I have a suspicion: could this be due to the very dry indoor air when it’s freezing outside? I noticed that my eyes now often feel (and look) dry, and indoor humidity is low, below 35% is normal these days. The drop happened roughly when temperatures dropped below freezing, which means heaters stay on 24/7. Also, if I measure a few minutes after getting up, my acuity is almost as good as before. But after just a little while in a warm room or in front of a screen, it goes down significantly.
There are some articles that describe how dry eyes reduce distance vision, so it could contribute. But is the effect really that strong on a week-to-week basis? Or am I on the wrong track here? Gotta say, I’m a little worried, because as the graph shows, nothing like this has happened since I started.
Have any of you had had similar experiences? Thanks in advance for any input!