So I did another round of testing. I’m starting to like this tool better and better.
First I started with normalized. I measured my eyes to left: 20/20.5, right: 20/24.5. I really like that you can do much more precise measurements than with Snellen. And the measurement is really straightforward and easy in the sense that there is no subjective decision making. Can I see rotating, or I don’t see any movement? If the latter, then use the switching buttons (switch the rotation and/or which one rotates). Usually it’s the same result, rarely a bit additional refinement with those.
What I also really love that you don’t need large distances to do this. I think it can be really useful for most Endmyopians, especially people not living in those countries where the standard size of flats starting at 90 m2
I could do the normalized testing with 2m away from the screen, which I think easily doable to almost everyone. And I would assume that the distance doesn’t really matter until the screen resolution is high enough to be able to show the small features of the circles. I think it would be worth to test this from mobile screen distance too, I can imagine it could work. I’ve did a quick test on my computer (with is a standard full HD screen with 96 ppi), and without glasses it works. With differentials I cannot go low enough, but mobiles has much higher ppi than a usual computer screen, so it can be ok. Especially if we don’t want to go below 20/20. Or even full hd laptop screens should do better (again, higher ppi).
Of course a bit drawback that to get 100% precise measurement you should have a calibrated screen (the app support screen calibration hardwares). But I think it’s still more precise than you usual printed Snellen or printed cm measurements, because at least your screen brightness is constant (I think generally the brightness should be maximised when doing such tests).
Also what is great that you have absolutely no chance to active AF in this test. There is no contrast to follow, nothing to AF on. You can just stare and either see the rotation or not.
What I don’t understand yet is that it gives overinflated numbers when I try to test without glasses. I can see the rotation with 20/102.2 left, 20/109.7 right without glasses. Which should be around -1.50? Which is waay too low. But maybe it is only for me because of this double visions issues? Because what I can see in this case is like 6-8 circles and only 1-2 of them is moving. Or to be more precise: I see two large overlapping grey blobs, and there is 1-2 moving part of the large grey blob I may need to actually read the manual if it talks about this case But given that it’s intended for optometrists use I can imagine they don’t even tried to deal with this case, because such high myopia the optometrists would anyway put some glasses on the subject.
So the huge advantages of this test:
- No need to have large distances
- No (or way less) chance to AF during measurement
- No subjective decision making, it’s either rotates or not
The only drawbacks I see so far:
- The PC program is a bit unstable and not too intuitive and absolutely bloated for our purpose (it’s intended for optometrist use). But this doesn’t influence how good the method works
- You need a wireless mouse or keyboard or set-up that you can control your PC with your phone to adjust the settings. Neither is a really big problem, but you won’t buy a wireless input just for this, and the latter may be a bit too tech-savvy for many people. I mean it’s just “download this program, next-next-next install” on PC, and downloading an app for mobile (works on both android and ios), but yeah… Their iPhone - iPad pair programs solves this, but then you need both an iPhone and an iPad.
- For some reason for me it doesn’t give proper results when I try to use without glasses. I suspect I am the exception. Or maybe it only problem for high(er) myopia and should be ok when my uncorrected vision is closer to -2.00? (so to where my differentials correct me) But maybe other people could test it @NottNott have you gave a chance to this? I know you measure regularly too.
The first two problem is “just” user interface problem an can be solved, has nothing to do with the actual method. The latter is a bit bigger problem, but honestly even if I can only test my eyes with glasses I don’t find that a really big problem, because for glassless testing cm measurement anyway more practical at my myopia.
So for what to use this?
- I think a good practical usage is to assess objectively how good you can see with your normalized. Based on my testings you cannot deceive it by more light, or trying to look a bit or “yeah, maybe that’s not really blurry”. It either rotates or not. If I would have used it to assess my vision with normalized when I’ve reduced too fast, I would have definitely not reduced. @NottNott it can be useful for you too I think
- Obviously it’s good for regular distance vision testing. Seems to be pretty consistent for me so far. As mentioned I can only do the testing with some glasses which is a drawback, but anyway at my myopia it would be more precise to use differentials for measuring. So it can be used a “distance vision” testing pretty well, with similar precision than what we can achieve with cm measurements in “close-up”.
- Theoretically it would be also a great tool to assess how good your differentials. But on my screen I cannot go small enough at my close-up distance to don’t see rotation. I have to go back to ~80-90 cm. But it’s an only 96 PPI screen, so… it can be also useful for this based on the setup.