In the world of vision rehabilitation, there are a few staple techniques such as the Brock string, Hart Charts, and vectograms that improve a patient’s visual function. Every now and then, these techniques need to be manipulated to increase the visual load and thus visual performance. In my residency, I have had the opportunity to work with patients from 2 to 82 years of age who have benefited significantly from vision therapy and rehabilitation. Granted, the sessions are organized differently for a two-year-old, but it remains true that all patients need change to stay motivated. As progress is made in therapy sessions, I have utilized some methods to spice up the routine in an effort to keep the patients interested and make their visual system more dynamic. Therapy techniques can be made easier or harder depending on each stimulus. Before using these adjuncts, be cognizant of your patient’s abilities. Use these methods to accent the therapy techniques at the appropriate progress level. All techniques listed below were learned through the contribution of the multiple instructors that I work with in my residency.
1. Laser or Flashlight
Feedback is an important aspect of therapy techniques. It helps a patient self-correct
and recalibrate their visual system. There are multiple ways to provide feedback during therapy. Visual feedback can include diplopia awareness, as well as a sense of luster and clarity. If a patient is able to recognize the small changes in the visual system, they will be more responsive to their visual environment. However, teaching awareness of the subtle visual changes that occur with vergence and accommodation is not an easy feat. To aid with this concept, the use of flashlights and laser pointers comes into play.
Laser pointers can be used with an saccadic activity to provide the patient with feedback of the latency and accuracy of their eye movements. In a severe ocular motor dysfunction case, I like to start with an activity called Post-it saccades. Begin with using 4 post-its labeled 1-4 and place them on 4 four corners along the wall. Next, place an X on another post-it and place it in the center. The goal of the activity is to use the light as feedback for the patient. Once they look at one of the post-its, they must use the laser and direct the light on that post-it. This will help them realize how quickly they can transition between the post-its and how accurately they point their eyes on the post-it. You can also add a Hart Chart to the mix and cut it up in four corners. Again, the patient directs their eyes to the chart and uses the laser as feedback. Once they look at a chart on one of the four corners, they read across the first row on that corner before proceeding to the next chart.
Laser pointers are also useful in teaching a patient about stability of fixation and pursuits. You can use a piece of masking tape or draw a maze on a white board and have the patient use the laser pointer to follow within the lines. The laser, once again, gives them feedback about the smoothness of their pursuits and stability of their fixation.
These activities are great for home therapy and should be a part of initial therapy. Once fixation, pursuits, and saccades are improved, you can integrate vergence and accommodative therapy techniques.
Pegboards have the reputation of being used for fine motor techniques. However, their purpose can be manipulated to encompass a variety of eye tracking techniques. Eye tracking activities are often performed in vision therapy to help with reading mechanics and efficiency. Patients with tracking difficulties complain of skipping lines while reading, re-reading the same line and poor reading comprehension. This makes sense, because if the brain has to exhaust energy trying to figure out where to point the eyes in space, it will have difficulty with higher level cognitive tasks such as remembering what was read.
Adding a pegboard to a tracking technique touches on the concept of intermodal therapy. In this case, visual-motor therapy. The Hart Chart has been ubiquitously used for tracking techniques including saccades work and near/far accommodative work. One way that I like to manipulate a mundane Hart Chart technique is by adding pegboard matching. This technique utilizes the concepts of visualization, visual memory, fine motor and accommodation. Set up a Hart Chart 6-8 feet away and have the patient sit in a chair with a 10×10 pegboard and a box of pegs. Start with their first name. Instruct your patient to track along the chart row by row and find letters that appear in their first name. Next, insert a peg in the corresponding spot on the pegboard to mirror the location of the letter. Most people are pretty good at spelling their own names, which minimizes the memory demand. However, looking back and forth between the pegboard and the Hart Chart adds a near/far accommodative demand and encourages the patient to track and visualize simultaneously. Once they have found a letter, then need to visualize its place on the pegboard. Placing a peg in the pegboard gives the patient motor feedback to the accuracy of their tracking. To increase the load, you can use unknown words where the spelling also needs to be remembered and visualized in order to perform the activity.
While patients may not have a pegboard at home, this activity can be simulated by drawing a 10×10 chart on a piece of paper and some M&M’s!
A metronome is a great tool for intermodal therapy. It adds an auditory component to a visual technique. Since this technique will require integration, you must make sure your patient first develops good visual mechanics. This means their accommodative and binocular skills should be adequate. This is especially true in your brain injury patients who will often have a brain filtering issue due to axonal damage in the dorsal stream. Once the mechanics are solid, you can now focus on top-down processing so that the brain exerts less energy on the physical act of converging, accommodating, etc. A metronome is a sneak peek into real-life situations where a person will need to accommodate, converge, diverge, and react to other senses simultaneously.
Gone are the days when you needed to spend $20+ to purchase a physical metronome. Today, you can easily access one on the internet via various applications. You can even download it on a smartphone! The application that I have downloaded, for free, on my phone is called “Pro-Metronome.” Now, I am no musician, so my knowledge about how to use a metronome was limited, but the application is fairly easy to use. You can adjust the tempo of the beats depending on your activity. Then, you can have the patient perform the activity on the beat or after a certain amount of beats. Anticipation and awareness of the count of the beats before performing the activity adds another level of cognitive load.
I have used this application with the Brock String in a couple of ways. First, the patient has to jump between the three beads on the click of the metronome at a preset beat for a jump ductions activity. Next, they perform the bug on string activity, but here, they need to wait for 4 clicks to converge from one bead to another. This same technique can be used for jump ductions between vectograms as well. Set up 2 Vectograms, one for base in and the other for base out. Then have the patient look back and forth between the two vectograms with a separation of 4 clicks of the metronome. They have to maintain the single and clear image of the vectogram for 4 clicks of the metronome before increasing the demand. Other techniques used with the metronome are Lifesaver Cards or Eccentric Circles where you can have the patient switch from convergence to divergence within the card at the click of the metronome. Finally, if you are performing a tracking activity such as Hart Chart saccades, you can use the metronome as a cue to say the next letter. All of these activities can all be performed at home for home therapy by downloading the metronome application. As you introduce new techniques in the therapy sessions, each one can be loaded with the metronome.
4. Balance Board or Walking Rail
Balance boards and walking rails are fun and effective tools in vision therapy. Whether you’re working on body awareness or simply trying to calm a hyperactive kid, these adjuncts can help patients solidify a technique. Body and spatial awareness are important parts of vision therapy techniques. Once a person is able to figure out where they are in space, they will be able to direct their eyes in the visual world. It is now being understood that if certain primitive reflexes aren’t integrated, it can pose a problem for postural and visual development. For example, kids who appear low tone and lethargic may demonstrate a convergence issue. It is important for this population to develop that core strength and stability which can help with eye teaming. In the brain injury population, the vestibular ocular reflex is disconnected from the visual system. Meaning, the two don’t play well together and their offset can evoke symptoms of disequilibrium and dizziness. Balance boards and walking rails can help integrate the senses during therapy.
Balance boards and walking rails can be coupled with a number of vision therapy techniques. They can be used with a Brock string to help build core stability in your convergence insufficiency or exotropic patients. First, start by having the patient simply stand on a balance board and perform the Brock string routine. You will be surprised how your low tone kids suddenly establish a better sense of convergence once they learn how to stabilize their core on a balance board. Next, add walking to the mix along the walking rail. This activity also involves a sense of peripheral awareness along with spatial awareness. Walking rails can be used with Hart Charts as well to train saccades. In this technique, separate two Hart Charts, horizontally or vertically. Next, instruct the patient to walk along the rail and read a row of letters from one chart followed by the next row of letters on the other chart. In addition, challenge your patient to walk at a speed such that they arrive at the end of the rail as they get to the end of a row. This builds visualization, spatial awareness, as well as eye tracking. Walking rails can also be added to Lifesavers and Eccentric Circles to make jump duction techniques more dynamic.
At home, a balance board can be replaced with a pillow with similar techniques. Instead of building a walking rail, a patient can use masking tape on the floor to follow along while reading a hart chart.
5. Yoked Prisms
The visual system is a dynamic process and, as such, the brain needs to constantly recalibrate to adapt to different visual environments. Correcting a sensorimotor mismatch allows the brain to learn. Yoked prisms simulate an artificial environment by shifting an image thus requiring the brain and the eyes to make a motor movement to correct it.. This causes the visual system to adapt, become more dynamic, and respond with accuracy. By shifting an image, a patient not only has to recalibrate where to point their eyes in space but also make postural adjustments to maintain balance. Yoked prisms are meant to be used towards the end of therapy, once the patient has mastered the basic mechanics. The amount of prism used usually varies, but in my practice, I prefer 8 to 10 prism diopters. Prisms should be used in all directions to maximize the efficacy of the activity.
Any visual/motor technique can be enhanced with the use of yoked prisms such as Wayne Saccadic Fixator, Marsden Ball Catch, and Brock string. The Wayne saccadic fixator can be set up for 30 or 60-second intervals of flashing red lights. The patient’s instructions are to catch as many red lights within the allocated time. This task requires accuracy since a light will only be counted if the button which it lays upon is pressed. Adding yoked prism to this activity shifts the image of each button and its corresponding red light. Thus, the patient has to correct this mismatch and recalibrate their visual direction. Try this activity in all directions of prisms. Playing catch with yoked prisms is a great way to tap into balance and visual motor abilities. Instruct your patient to follow the ball into their hands for increased accuracy. Do 5 trials per direction separated with intervals of no prism. Every adjustment the brain has to make while wearing the prism and after removing the prism causes it to learn and adapt. This technique can be used at home while playing bean bag toss. To add another level of difficulty, have your patient stand on a pillow while catching the bean bag.
Yoked prisms can be incorporated into vergence techniques with the Brock string. Patients may have a preferred gaze which helps them converge or diverge so use that as your starting point. If they have improved convergence range in downgaze, use yoked base up prism to put them into that gaze and improve fusional ability. This technique is great for home therapy because it will help the patient expand their range of comitancy.
Vision therapy and rehabilitation can make a significant impact in the day-to-day functionality of a patient. Whether your patients are kids or adults, visual performance has been shown to improve with in-office therapy. When the routine activities get mundane, try incorporating these 5 techniques. Not only will they keep your patients motivated, they will also help maximize their visual skills.