The vision therapy adventure continues. My second round of appointments brought some new exercises for voluntary vergence control and some updated vision status measurements. I also suggested some VR applications to the vision therapist. Four more weeks of home exercises until the first follow-up with the doctor to check progress.
I'm starting to see vision impacts, some of which have required behavior changes.
I frequently read before bed and I did so without glasses most of the time in the past (since the temple would crush between my head and the pillow). Prior to starting vision therapy, my right eye would simply rotate out and suppress doing this. As it has become more engaged and less suppressed, it's become both distracting noticing it turning off and it causes visual discomfort when it doesn't. I have stopped reading without glasses because of this (which is probably good anyway since I'm sure doing so contributes to suppression).
My ability to converge on objects close to my face has improved significantly. When we first started, it was very difficult to keep both eyes focused on the Brock string even a little bit close to my face, now there isn't much difficulty in the exercise beyond having to give up on accommodation with minimum focus distance limitations.
Which brings up this: one negative I've noticed, unrelated to vision therapy, is the apparent onset of presbyopia. Minimum accommodation in front of my nose is now around 4 inches. I had not measured it previously, but it was definitely closer before. Not so bad as arm-length reading yet, but I guess we're on our way.
We re-measured my right eye suppression using polarized glasses and a mirror to test the distance at which I am no longer able to see my right eye (read: right eye is suppressed). The first time I did this starting vision therapy I was at 5 feet. I have not changed much here and we measured 6 feet this time (which I'd guess is within the range of regular variance). We also did the anaglyph letter chart and I was able to see letters in my right eye (which I could not do at all on my first visit) at 6 feet, so there's definite improvement in eye control there even if the measured suppression has not changed much (if at all).
We are working on voluntary vergence control (read: controlling where your eyes cross independently of accommodation). Children can generally do this very easily (e.g., crossing their eyes), but adults often have challenges—particularly adults like me with amblyopia. The fusion circles exercise—controlling eye vergence to either converge or diverge two separate circles into a single circle and get a 3D effect—I was assigned at the start of therapy has continually eluded my ability to make it work. I can diverge relatively easily (as this is basically what my right eye does when it shuts off anyway), but convergence has been very difficult.
To build up to this skill, we used two tools:
- Variable vectographs in a lightbox. This is basically two printed (polarized) transparencies in a stand that are separated slowly while you wear polarized glasses. As the two images are separated, and if your eyes maintain a lock on both, then you'll see a 3D effect as they get farther apart.
- A software-based anaglyph (red/green) autostereogram shape identification exercise where the two images are moved farther apart as you are able to successfully focus and identify the object in the autostereogram.
I had reasonable success with both of these. Convergence was definitely harder than divergence.
Back to the fusion circles, I have managed to work up to being able to get my eyes pointing in the right direction using a pen nearer to my face as a vergence aid (i.e., something to cross my eyes at)—enough so I can get the requisite amount of double vision (3 circles) needed to pull in a 3D image but I have not yet been able to combine the convergence with correct accommodation in order to focus the circles. I've gotten very close a couple of times, though, so we're making progress.
One of the things that got me interested in vision therapy a few years ago was the emergence of VR software for vision therapy (VividVision, in particular). Unfortunately initial accessibility promises ended with it being provider-only (which I assume is related to FDA regulations). As there weren't any providers in my area offering the software, I lost interest for a while.
I brought this up with my vision therapist in the last appointment and she's going to raise it with the doctor. Fingers crossed.
In general, the vision therapy software space is disappointing from a user perspective. What is available to consumers is either mediocre, expensive, or expensive and mediocre. Everything else is only available through providers (and is also expensive—and probably mediocre for all I know).
Except for the VR stuff, they're also all anaglyph, which is fine so far as it goes (the price of entry for red/green glasses is low), but it'd be neat to do the same thing with something like the NVIDIA 3D Vision frame shutter glasses. Anaglyph always has some light leak between eyes even when you're well-calibrated on the colors.
I am considering trying to put together something open source that works with VR or frame shutter glasses and offers a few simple games that would be appropriate for amblyopia (e.g., word search, 2048, snake, etc.). Re-implementing the autostereogram vergence exercise mentioned above might also be a good target. We'll see how motivated I can get myself, as it's a lot of learning from my starting point just to get to the point where I can put together something very basic.