Using the Brock String to Fix Strabismus: Tips and Tricks

The Brock String is the most iconic tool used in vision therapy. As an adult with strabismus, it took months of therapy before I was even ready to start using it. Now that I’ve been using it in daily exercises for the last 5 months, I’ve learned several tricks that are helping me use the Brock String to effectively train my eyes to work together and become straighter!

So how can a Brock String fix Strabismus? The Brock String is designed to give immediate feedback about where a patient’s eyes are pointing. It is a safe place for double vision and allows those with strabismus to find and manage where their eyes are engaging together and slowly move it to the “correct” spot. Peripheral vision, touch, balance, prisms, red/blue glasses, and more peripheral vision combined with the Brock String can lead to faster results.

Most of the Brock String tutorials that you find are designed for people who do not have strabismus. They are fantastic once you get to the point of normal-ish vision, but for strabismics, there is a loooong road to get to that point.

I am going to lead you through what a Brock String is, how to use it and then share details and pictures of all of the tricks I have developed over the last 5 months to make is super effective for straightening my eyes. Let’s dive in!

What is a Brock String?

The Brock String is a tool used in vision therapy. It is super simple and consists of a rope that is generally about 10 feet long with 3-5 adjustable beads on it.

How and Where do I Set my Brock String Up?

One end is attached to a door knob or drawer handle or pretty much anything you can attach it to, while the patient holds the other end up to their nose and pulls the string tight. Make sure you have plenty of room to back up

For me, a beginner, I like to have the beads fairly close together and pretty close to my nose. I have the beads spaced about every 12 inches. Eventually, the goal is to move them farther apart and farther down the string, but that takes time and practice! This part definitely takes some adjustments based on you, as your optometrist for a starting point and they will help you.

If you choose to set up near a window, make sure that there are blinds or curtains. Bright light from a window can make it more challenging to have success with the Brock String.

Where Can I Purchase a Brock String?

I highly recommend getting your Brock String out and using it while you read this, it will all make much more sense! If you don’t have one just head over to Amazon or etsy and there are a ton of options.

Vision Therapy Mom makes several cute versions of Brock String with beads that you can customize to match you or your child’s interests.

Amazon also has plenty of options to choose from, click here for one that would work well.

I actually prefer the beads that have a button to push down when you slide them up and down the string. They have a larger hole and my brain has an easier time seeing two strings going through it than with smaller beads. I got mine from my optometrist and wasn’t able to find a Brock String with them online, but you can buy the beads and string separately on Amazon and make your own.

How to Use a Brock String for Exercises

There is so much that can be done with a Brock String, but I will break down the basic idea so we have a starting point and then talk about adjustments that can be made. If you have strabismus, it will not be this easy and you may want to scroll down to the section on troubleshooting.

Here is the Utopian version of the Brock String Exercise procedure:

  1. Attach one end of the string to a door, hold the other end up to your nose, pulling it tight.
  2. Look at the closest bead.
  3. Use your peripheral vision to notice that there appear to be two strings coming into the bead, and two strings leaving the bead, forming an “X.”
  4. Shift your eyes to the next bead and notice how the “X” is now going through the bead you are looking at.
  5. Continue looking at different beads and seeing the “X.”
  6. Move the beads to within one inch of your nose and further down the string to expand your abilities.

If only it were that easy! The first time I looked at a Brock String was when my son was in vision therapy for convergence insufficiency. I knew the idea and understood what I was “supposed” to see, but no matter how hard I tried, all I saw was one string. I couldn’t even get the faintest hint of a second string, let alone an “X.”

Read on to learn about what I did to not only find that second line, but also find the “X.”

Troubleshooting Brock String Exercises

What can I Try if I Only See One String?

If you can only see one string, your brain might not be ready for this exercise yet. One string means that your brain is suppressing (ignoring) the image from one of your eyes. Make sure to wait until your behavioral optometrist tells you you’re ready.

Your optometrist will probably have you work on anti-suppression activities with a red lens patch or red/green glasses to help break suppression before you start working with a Brock String, but the Brock String can also be a powerful anti-suppression tool once you get started.

Here are some ideas that may help wake up your non-dominant eye so that you can see both strings.

  1. Do Anti-Suppression Activities First
  2. Adjust the Lights
  3. Use your Peripheral Vision
  4. Use a Prism
  5. Use Red/Blue Glasses

1. Before using the Brock String do your anti-suppression activities with red/green or red/blue glasses. Your Vision Therapy office probably has sent you home with plenty of options like playing cards or other activities.

If you don’t have any, AmblyoPlay is a great computer program with excellent anti-suppression games and is a favorite of mine. I also have some printables and ideas over on my post about the red lens patch that would work well if you aren’t into using screens. There are also a bunch of apps that you can download on your phone that are great for waking up both eyes.

Working on anti-suppression word puzzles with my red/blue glasses.

The key is to do something that forces both eyes to work. Doing this first can wake up both eyes and make it possible to find that second string.

2. Try adjusting the lights. Turn them off and see if that helps. Block out any bright light coming in through a window. This helps me a ton, but maybe for you the bright light helps. Play around with it. Sometimes adjusting the light makes a difference.

3. Refer to the picture below for the colors, but just switch colors for whatever you have on your personal Brock String. While looking at the near blue bead, try to see the red or yellow bead using your peripheral vision. Can you find two red or yellow beads out there in your peripheral? They may be blurry and could come in and out of focus.

If you want to become a master of peripheral vision, check out the “Mastering Peripheral” course that I created to help people exactly like you learn how to hone their peripheral skills in a way that makes vision therapy exercises MUCH easier.

When you are able to see two strings or two beads in your peripheral, but not near the blue bead you are focusing on, move the red or yellow bead closer into your view by sliding it closer to the blue bead you are actually looking at.

Visualize the string as the z-axis and estimate where the different beads fall on the axis (you can read more details about the z-axis here). Try to see the space around each bead and the space between your nose and the bead.

This takes time. There were several days where all I could get was a distant sense of two strings, eventually my brain decided that it wasn’t harmful and allowed both strings to come into view. Even still, the strings and beads in the peripheral are much more concrete than the bead I am focusing on.

Peripheral is IMPERATIVE! Do not brush this step off, it is the most important one.

4. Use glasses with prism if you have them. I was given blank glasses with a fresnel stick-on prism by my ophthalmologist and my optometrist wasn’t terribly excited about me using them, but the first time I was able to see two string was when I put them on.

I wasn’t able to fuse the beads into one or see the “X,” but for the first time I could finally comprehend what I was looking for. Somedays when I was struggling to do the exercise without my glasses, I would just put them on for a minute or two to remind my brain and then take them off again and do it without the aid of the prism.

5. Red/Blue glasses are a tool that I still use consistently with the Brock String every single time I do it. I no longer need the prism glasses, but I do need the red/blue glasses.

Because the string is white and each eye sees through a different color, the string your left eye sees will be blue and the the string your right eye sees will be red or visa versa. Since the strings are different colors you have instant feedback about which eye you are using or suppressing.

I find that my brain fights less against the logic. With a simple, white string my brain fights seeing the “X” because I know that logically there is only one string. But when they are different colors I feel like I am searching for two totally separate objects and my brain is way more on board.

I am able to not only see both strings, but I can also see the “X” much more clearly when using red/blue glasses. Give them a try.

What Can I Try if I see Two Beads and Can’t Combine Them

Once you are able to see two strings and two of each color of bead, the real fun begins. This is where you have to train your brain and eyes to align at specific points in space and it is not easy! If you have an eye turn, you will most likely see double of the bead you are looking at. Instead of crossing right through the center of the bead you are focusing on, the string might cross before, after, above or below the bead.

These pictures are examples of what it may look like at first, but just know that if you have an eye weakened by amblyopia, one of the strings will probably be more blurry and not as bold.

The goal is to be able to look at a bead and see it as single with an “X” that is made by the strings crossing right through the center. If you aren’t seeing this, here are some ideas that have helped me get better in this area. Some of them have come from my Optometrist, others from Instagram tips, others from trial and error with hours and hours of practice. They are not necessarily in order and you will probably need to combine several of them to have success.

  1. Start with Red/Blue Glasses
  2. Use Peripheral!
  3. Tap the Bead
  4. Pinch the Bead
  5. Move the bead up and down the String
  6. Close/Cover the dominant eye

1- Start with Red/Blue Glasses– I struggle to just start with the Brock String cold turkey. Do all the things I suggested above, but I find the red/blue glasses are the most helpful! They really wake my brain up and get it ready for work.

Put the glasses on and look at the Brock String and find the two strings, then if they aren’t lined up, use steps 2-6 to line the beads up correctly. Once you have mastered it with the glasses on, try taking the glasses off and doing it without them!

2- Use Peripheral! This is the key for me. It is so much easier to get both eyes working in the peripheral space and then slowly move towards central vision. I promise, don’t skip this part even though it doesn’t feel as concrete. Read my post about the z-axis, follow the steps and ideas that I mentioned earlier, and then add on these new ideas.

Peripheral Trick 1:

I will assume that while you are looking at a bead, you see it double, right? Using the picture below let’s assume you are looking at the green bead and this is what you see. Don’t stress because even though you are seeing the green bead as double, the strings are lining up at some point. Keep your central focus on the green bead and then use your peripheral to follow the strings and find the point where the strings are crossing.

If you look down the Brock String at the GREEN bead and it looks double, like in this picture, open your peripheral and notice down the string where the strings do cross at the BLUE bead. Keep the focus on the green bead. Slide the blue bead a little closer to the green one and then continue using your peripheral to see the string cross there. Keep sliding them closer until you are able to see the strings cross at the GREEN bead, where you are focusing.

The strings seem to line up at a bead in the peripheral, in this case it’s the blue bead. Slowly move the blue bead towards the green and then continue using your peripheral to see the string cross there. Keep sliding them closer until you are able to see the strings cross at the green bead, where you are focusing.

Combining this technique with tapping and pinching works really well. The idea is to be able to actually see the strings cross at the bead you are focusing on.

Peripheral Trick 2:

Focus on a bead that is at least two beads away from your nose, in the picture below I will use the blue one. While maintaining focus on the blue bead, look for the two red beads and the two green beads in your peripheral vision. I almost ignore the blue bead for a second while I’m using my peripheral to pay attention to the other four beads. I look for the strings that connect each red bead to a green bead. After I work to become aware of those beads and their strings, I notice (or tell my brain) that the strings cross right through the blue bead.

Visualize the line connecting the beads just before and just after the bead you are focusing on using your peripheral vision. Find the spot where the strings cross and then tell your brain to find the blue bead there. It sounds a little crazy, but works so well!

There is definitely shifting going on from central to peripheral, but as I have practiced this technique, I am able to maintain the central and peripheral at the same time more often. The idea is to see the “X” by first seeing the beads at the endpoints of the “X” and then slowly moving (this might take some coaxing) from the peripheral towards that center blue bead to see the “X” cross right through it.

Tap the Bead

This is very simple, but is super helpful. Just tap the bead with one finger. I like to get all telepathic and tell my finger to tell my brain and eyeballs where the bead is. When you tap the bead, try to sense how long your arm is and how much space it takes up and then use that to also think about the space between your nose and the bead.

Sometimes I push the bead to the left or right and move the strings and that resets my brain and moves things into alignment.

Pinch the Bead

This is similar to the tapping, but with pinching think more about the size and shape of the bead and then telepathically transfer that knowledge to your brain. While you pinch the bead you can slide it closer or further away and sometimes the movement helps the eyes align and fuse the bead into one.

Close/Cover the dominant eye

Sometimes it feels like my dominant eye does 90% of the work and my non-dominant eye does about 10%. Because of this, everything is shifted in my view to be in front of my left eye. Covering or closing that eye brings the right eye view into focus and as I uncover my dominant eye, I try to find the balance so that both eyes are seeing equally.

There is no one trick or idea that will work for everyone every time. Every day I face a new challenge with the Brock String and I combine all of these ideas to find success. The more I practice, the easier it becomes.

After 5 months of Brock String work, I can easily see the “X” on the bead closest to my nose. With a little work I can see the “X” on the second bead. Using all of these tricks I am able to see flickering moments of an “X” around the third bead. The fourth and fifth beads are still double and I can’t quite fuse them into one, but I am able to lessen the gap that I see between the beads.

This takes time. Be willing to work hard to train your brain. Hard work will pay off and be very effective, but you have to be willing to stick it out, day in and day out.

Here is a progress picture that I took just a few months after I started the Brock string, it has helped me gain so much more control of where my eyes are pointing and is an excellent tool for vision therapy! It’s not the only tool, but it’s a great one!

Don’t be alarmed when you see the strings jumping back and forth all over the place. Just relax, take a deep breath and try to see the whole string and the air all around it simultaneously. The better you can become at viewing the whole room simultaneously, the easier this and every other vision related task will become. Get help with that exact thing in the Mastering Peripheral Course.

Good luck! You’ve got this! Feel free to share your favorite Brock String tricks with me, I am always looking for new ways to have success with this exercise.

Note: This post is designed to be an aide for individuals who are currently pursuing vision therapy under the direction of an optometrist. If you do this without their direction, it can cause double vision and will not be able to fully fix your strabismic eyes. It is one of many tools used in the process. I am not a doctor and would always recommend checking with yours before you try these things.

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