Saturday, February 5, 2011

Do it yourself TBI

No, I don't mean traumatic brain injury. I mean Translid Binocular Interactor!

In my first few weeks of vision therapy, I went to the OEP online store and bought Effective Strabismus Therapy, by Dr. Israel Greenwald. I didn't really have a good reason, except that I had 30 dollars and wanted to know everything.

The book isn't an easy read, though. It's written for other optometrists, and seems to use the language of a scientific journal. It also talks about a bunch of VT instruments and gadgets that I either don't understand or know if have access to (Haidinger brush? polachrome orthopter?) Slowly, though, the more I read it, the more I understand. Going through vision therapy, getting experience with how my eyes work, and learning VT lingo is helping, too. I recently reread the chapter about monocular exercises, including exercises that help fix that jerky tracking on the strabismic eye. And I think I'm actually starting to understand WHY it's all jerky like that. Amazing! Maybe I'll write a blog post about that later...

Dr. Greenwald is still around and treating patients in New York City. If you read this, Dr. Greenwald, thank you for treating us strabbies and writing books about us!

Anyway. One of the things that I learned about in the book was a device called a Translid Binocular Interactor, or TBI. Now, as I understand it, a TBI is a device that puts rapidly blinking lights in your suppression zones. I'm guessing the theory is that if you put blinking lights in your suppression area, it will make it harder to suppress. You know, because of the blinking lights and all.

Some TBI devices are just boxes that you hold up to your eyelids, like this. But the TBI that I read about in Dr. Greenwald's book had the lights on movable clips. If you were an esotrope, you would clip them on the outer edges of your glasses, or even on the arms of your glasses. If you were an exotrope, you would clip them on your glasses toward your nose. Basically, you're placing them in your area of suppression.

I thought this TBI gadget sounded useful and I immediately had to have it. But my vision therapist / optometrist didn't own one, and they cost over 250 dollars for the kind that clip onto your glasses. 250 dollars for TWO blinking lights?! Are you kidding me? Surely, I could come up with some kind of cheaper substitute...

I'm not an electronics person, though and I don't really get how all that stuff works. Volts and amps and ohms... I just don't understand. But surely, making a light turn on and off is not something that requires a graduate degree in electrical engineering to figure out.

Then I remembered. LED throwies. LED throwies are a a coin battery, an LED, and a magnet, all taped together with electrical tape. The LED lights up, you throw them (hence throwies), and the magnet makes them stick to whatever (metal) structure you threw them at. They're kind of like electronic graffiti.

The LED lights up just by making contact with the coin battery. No wires, no complicated electronics. I thought to myself - What if I use a blinking LED instead of a regular LED, and use an alligator clip instead of a magnet?

So I went to RadioShack, gathered my supplies, and made my own homemade TBI!

The only blinking LED that I found was red, and certainly did not blink 7-10 times a second. I didn't really mind, though. It's a close enough approximation for my purposes, and doesn't cost 250 dollars.

Here are the instructions for making your own:

- 2 coin batteries
- 2 5mm blinking red LEDs from RadioShack
- 2 alligator clips (Note: the clips shown in the picture are too small to tape the coin battery to. Use bigger clips.)
- stiff paper (I used a manila folder)
- electrical tape
- scissors

Step 1:
Cut out a strip of stiff paper that will wrap around the coin battery.

Step 2:
Tape the paper to the battery using electrical tape. You now have a little pocket on each side of the battery in which to insert the "legs" of the LED.

Step 3:
Curl the "legs" of the LEDs, like the one on the left. This will allow the LEDs to fit into the "pockets" on the batteries.

Step 4:
Put electrical tape around the "teeth" of the alligator clips. This will protect your glasses from teeth marks. (Note: Again, the clips pictured are too small. Use bigger ones!)

Step 5:
Tape the coin battery to the alligator clip. (The clips pictured are now the right size.)

Step 6:
Insert the LED into the pocket. It will start blinking. Clip to your glasses and have fun. (Note: the LED will only light up if each "leg" is on the correct side of the battery. The short leg goes on the smaller side of the battery, and the long leg goes on the bigger side of the battery. If you put the legs on the wrong sides of the battery, the LED simply won't light up. Switch the legs around and try again.)

I've played around with these, and I've found it best to position them so that you don't actually have the LED directly in your field of vision. Position them so that you get indirect flashes of light. I think it's called Translid for a reason. While wearing them, do whatever vision therapy exercise that you wish. I've used them while using the Brock string, to help me see all four strings.

When you're finished with your exercises, pull the LEDs out of the pockets. This will turn your device off and save your batteries.

WARNING: I am not a doctor or eye care professional of any kind. I don't know if it's safe to put RadioShack LEDs up to your eyeballs. Do so at your own risk. Also, those with epilepsy should not use flashing lights near their eyes, either.


  1. yes, well, we were kind of 'testing it out.' I think the intention was to irritate the suppression, as you say.

    We used it at my appointment after my exciting taste of the 3D world. I was using red/green glasses and looking at text. I was supposed to use an orange marker to circle letters hidden in the 'words' of the text (maybe you know this one.)

    Anyway, it was actually impossible for me to do it, because I just could not do it (work mono in a binocular field) even with the blinky lights discouraging suppression. I wasn't suppressing, but my eyes weren't working together.

    So even though I had some 3D, there is still a ways to go for me (before I do red/green solitaire, for example.)

    I look forward to learning more about it when we are using it therapeutically, rather than just 'testing it out'-ly.

  2. Yeah, some of those red/green activities are quite difficult. Sometimes everything moves around and goes out of alignment and flashes between visible and invisible. I haven't heard of the one that you were doing though. I think I may understand it, but you probably need to include it in your next blog post ;)

  3. I just take a handheld bright LED light and shake it in front of my closed eye that is experiencing the supression. The shaking creates a faster blink. The faster the blink, the more antisupression you should experience as it really excites the eye. I was going to duplicate one of the expensive items like you did, but to get the cycles fast enough, it wasnt worth the problems. Shake the light!