Robert Nurisio, COVT, on Mental Minus

Here is a new series of excellent blogs posted by vision therapist Robert Nurisio, on Mental Minus:


The first time I encountered Dr. Harry Wachs was in 2005, not long before his 81st birthday. He and his wife Ruth, had traveled to San Diego for Dr. Wachs to impart his incredible knowledge and vast experience on the thrity five of us lucky enough to call ourselves his seminar audience. That particular seminar was conducted over three separate weekends, spread out over a summer, and lured some of the great doctors of our time to participate. “Harry”, as he insisted we refer to him, opened doors through his teaching whose existence may not even have occurred to us before meeting him. The lessons learned from that seminar still resonate loudly in the years since Harry’s passing.

One of the gifts Harry left us (there were literally hundreds) is an activity named Wachs Mental Minus. The activity fits within the hierarchy of monocular accommodative sequencing, concludes with a bi-ocular challenge, and asks the patient to build and maintain both awareness and regulation of their accommodative system as progress is achieved through the levels. Over the next week or so, I will offer my interpretation of the do’s and don’t’s of each level.

Level One – Tromboning

The goals of this level are multi-faceted. Along with changes in accommodation, patients may report SILO awareness, accurate or inaccurate spatial localization, awareness of their eyes changing, the speed or rate of change, and the possible need to increase or decrease their distance from the target.

Assuming our patients are sitting comfortably and in good posture, level one is completed with a patch on one eye. There may be times when choosing which eye to start with is significant (refractive amblyopia, etc), and other times where which eye goes first is less important. This is definitely something each Vision Therapist should discuss and decide with their Developmental Optometrist ahead of time as they prepare for the session beforehand.

Through trial and error, I have found that this level of Mental Minus is a bit counter-intuitive, esentially asking us to work backwards. Typically, with accommodative activities, the name of the game is to start small and work our way up in power, but that is not the case with level one. Rather, it’s best to start with a higher power and work our way down.

In most cases, we will begin with a -6.00 lens and a target with an age appropriate font size. The key factor is to choose a lens which causes the patient to exert reasonable effort to accomplish relative clarity. This aspect can also require the Vision Therapist to adjust the initial lens power based on the patient’s age, refractive status, and level of correction.

With the patient maintaining Harmon’s Distance, they are asked to place the lens in front of the open (non-patched) eye. The first step is to ensure the patient can clear the power of lens we have chosen, and if not, this is our opportunity to adjust, either by offering a stronger or weaker lens, until we find the lens power the patient is able to clear with some effort. Again, this is something each Vision Therapist should discuss and decide with their Developmental Optometrist prior to beginning this activity. Once the “ideal” lens is chosen, the lens can slowly be moved closer and farther from the eye while the patient maintains clarity. Remember, moving the lens away from the eye decreases the accommodative demand, while moving the lens closer to the eye increases the accommodative demand. At its closest, the lens should be flush against the patient’s face, and at its farthest, the lens should be no closer than a few inches from the target.

Subjective evaluations the Vision Therapist might watch for are:

Pupil restriction with an increase/decrease in Accommodation – the closer the lens is to the eyeball, the higher the accommodative demand the more pupilary constriction that can be observed.

Convergence or divergence of the eye under the patch as the lens is moved closer and farther from the open eye. Remember, vergence and accommodation travel together, so the more accommodative demand, the higher the rate of convergence and the lower accommodative demand, the higher the divergence.

Strenghth and balance of change is also important. As the patient trombones the lens, are they able to make the accommodative changes needed so the target remains clear at all times, or does the clarity “swim”, meaning it varies between blurry and clear as the patient completes the activity. Does the “swimming” occur when the lens is moving or also when the lens is held still?

Does the patient feel their eyes changing? Do they have that level of awareness? Can they use the information learned to recreate the accommodative posture?

What is their current level of awareness with respect to the changes in spatial awareness? Can they appreciate these changes? Are they able to localize – that is create a connection between the feeling inside their eyes and the current level of accommodative demand? Do they report any SILO awareness?

When the patch is moved and the activity is repeated with the other eye open, is there a difference in ability, feeling, or performance? Does the patient note their eyes hurt or are residually uncomfortable?

As mentioned above, the overall goal of this activity is to build patient awareness of many aspects of the accommodative system, including feeling tone and localization, to name a few. In terms of Skeffington’s Circles, this activity might be considered part of the “What Is It?” or Identification Circle; however, it is important to remember that when it comes to the visual system, no skill exists in a bubble. Other areas to consider are the “Where Am I?” and the “Where Is It?” questions as a reasonable understanding of both are included in the list of skills necessary to achieve accurate and efficient accommodation.

Stay tuned for level two!

(Actually, you don’t have to wait long. Here is part two:)


Real world changes in space and distance employ a SOLI response. That is to say, in real life, when objects get closer they become bigger, and conversely, when they travel further away, they become smaller. This premise seems to be at the basis of our visual logic in terms of how we “write” our spatial codes for maneuvering. Without thinking, we know if we see a car down the road and it appears to be getting bigger, it must be getting closer, and vice versa. It’s really a fascinating system.

With monocular lenses, although visual logic is employed, SILO becomes an available option to the patient. Remember, even with one eye covered, when we change accommodation vergence is still affected. So with a -6.00 lens, for instance, we stimulate accommodation to meet the demand of the lens and vergence is passively changed – meaning convergence occurs. The inverse applies for plus lenses and divergence. A key element to understanding all of this is remains in how lenses create a focal point, and we adjust our eyes to meet that focal point. Minus lenses create a focal point between our eyes and the target we are viewing thus giving the appearance of “smaller in”, and plus lenses create a focal point behind the target, which creates the appearance of “larger out”. Granted, this form of SILO can feel much harder to appreciate than the binocular version.

Level Two – Lens On Clear/Lens Off Clear

This activity comes by many different names, with the most common being “Monocular Accommodative Rock”. The entire emphasis of this level asks the patient to meet the accommodative demands of the lens. Key in all this is helping the patients understand it’s not the lenses which are making the change; rather, the lenses are causing a disruption, or conflict, which they, the patient, need to visually resolve.

With a similar setup to level one, the patient should be seated comfortable with an age appropriate text at Harmon’s distance. If you are able to offer them a slantboard or appropriately sloped surface, even better.

The activity involves asking the patient to place the lens in front of their unpatched eye, approximately in the same position as a pair of eyeglasses, while asking them to clear the image in front of them as quickly as possible. Once this is achieved, the lens should be removed, and again, the patient is asked to clear the image as quickly as possible.

As the Vision Therapist, our job (along with offering clear and concise directions), is to be observers. Does the lens we chose offer an appropriate demand to the patient? Is the patient able to achieve at this task with some effort but without feeling visually overwhelmed? Again, in the session preparation phase of our day prior to the patient’s arrival, we should have decided which power would be an appropriate place to begin, in terms of lens power. Some of this information can be gathered based on the success and/or struggles in level one, and any disparities can be discussed with the Developmental Optometrist. In our observations, we might be watching for pupil constriction, variable lags of accommodation (one eye seems to take longer to clear the image than the other eye), does the patient need to squint to achieve this task, is the eye under the patch converging or diverging appropriately, or do they even feel the need to move closer than Harmon’s distance to make the target clear? While squinting and changing their working distance is never optimal – remember, moving closer induces more accommodative demand – we can offer them assistance simply by changing the target size, adding more light, or even backing down the lens power some to see if they are able to achieve at an optimal level.

Along with flexibility, stamina, and control, a key element in this level is the patient’s awareness of where they are looking – remember “where am I?” versus “where is it?” – and the associated feeling tone in achieving clarity with the given lens. The resultant outcome hopefully being a SILO response.

A few tips to keep in mind:

  • Equality is important. Before the patient is ready to move on, they should be able to achieve relatively equally in both eyes
  • Avoid the snapshot. I usually try to work this activity twice, in two separate sessions, just to avoid any false positives
  • Patient Feedback – How do you feel about this?


The overall goal of Wachs Mental Minus seems to be to achieve an awareness, regulation, and control over the focusing system. More broadly stated, the patient needs to be able to maintain visual clarity of their world, no matter the accommodative demand, through the flexibility, stamina, and strength found in their accommodative system. Any anomalies, inadequacies, or inefficiencies may result is such symptoms as headaches, eye strain, squinting, and even an occasional experience of double vision. Obviously, all of these symptoms have undesirable consequences.

Many times, when viewing Skeffington’s Circles, it seems we become comforted by the idea that the “What Is It?” circle only involves accommodation. The “Where Am I?” and the “Where Is It?” circles seem to be a bit more complex when we consider body awareness, motor development, and even Z axis dynamics, so the idea that the Identification Circle is ‘easier’ might be an easy leap to make, but not so fast. When recalling that no skill in the visual system exists in a bubble, or to be a bit more cliche’, everything affects everything, we will quickly realize there is more to “What Is It?” than a patient’s ability to clear a lens. A lot more. We will dive deeper into this when reviewing Part 7 – the Bi-Ocular Phase.

Level Three – Don’t Clear

As a deliverer of Vision Therapy, there seems to be activities where our observations are more important, and some where those observations may take a bit of a backseat to the patient’s self assessment. It can be a delicate balance, and one where the therapist/patient relationship becomes a key factor in deciphering the patient’s true skill level. Truly, level three of Wach’s Mental Minus creates such a situation, as it actually asks the patient to effectively do nothing, and call it a success. At the risk of sounding cynical, this may be the level where some Vision Therapists get tripped up, as in certain circumstances, there can be a fine line between actively inhibiting a response and simply having no response. This is why constant communication with our patients is experience key.

For level three, our setup remains the same – comfortable posture, one eye occluded, Harmon’s distance, and age appropriate text.

As an aside, I received an email after posting level one asking why I suggested using “age appropriate font” rather than a more standard 12 point font to keep things consistent, and my answer is simply to neutralize the demand as much as possible. Generally speaking, most first and second graders use a larger sized font in the classroom, so my goal is remain in step with their current levels. Decreasing the font size will both increase accommodative demand (remember, size matters here) but also has the potential to become defeating if we push them too far out of their comfort zone. Obviously, this detail may vary office to office and doctor to doctor, but this is where my current logic falls. As they progress through the activity, we may consider a font size change, but at the beginning it’s important for me to start where they are.

Once we have confirmed our patient’s setup is optimal (posture, distance, etc.) the first step of this level is to have the patient place lens in front of their non-occluded eye, preferably at a similar distance to that of the lenses of their eyeglasses, imagining they were wearing some. The instructional set is fairly straightforward – “try not to let anything change” – remembering, of course, that our brain’s primary signal to accommodate is blur, and the lens may cause enough of a disruption that the patient accommodates before they are able to inhibit the action, so we should be watching for it. The higher the power of the lens, the higher the level of visual conflict is created, the more inhibitive control the patient will need to call up to achieve success. If a patient seems to be having trouble, an emphasis might be placed on how their eyes feel before looking through the lens, followed by asking if they are able to maintain that feeling no matter which lens we use. As with most levels in Wachs Mental Minus, feeling tone is key.

As the Vision Therapist, two key elements to watch for are pupillary response, as the pupil will constrict with accommodative stimulation (minus lenses) and dilate with accommodative relaxation (plus lenses). The second factor to pay attention to is the action, or inaction, of the eye under the translucent occluder. Because accommodation and vergence are intricately connected, when we move accommodation, vergence will secondarily respond; meaning, the eye under the patch will move. If the patient is successful in resisting an accommodative response, neither a pupillary response nor a movement of the occluded eye should be observed when the lens is placed in front of the non-occluded eye. The same holds true when the lens is removed – we should observe no changes. The process can be repeated on the other eye with a goal of equal levels of control and regulation from one eye to the other.

For a long time, this level of Wachs Mental Minus was confusing for me. Why would we want our patients to find success in making nothing happen? What I came to realize after some time is the need to control our inactions is just as important as the need to control our actions. After all, what would good fixations look like if we couldn’t make them stay still? Active resistance to change and movement through a controlled inhibition is a skillset unto itself.


An interesting part of Wachs Mental Minus is the manner in which it addresses all aspects of accommodation, from the stamina and flexibility of the mechanism, to the feeling tone attached to each position, to the awareness of the spatial changes we make in learning to accurately accommodate – it is all there.

Please note, in no way is there a suggestion of surprise in my commentary; more like admiration. Dr. Harry Wachs was a master when it came to human development of the visual system, and although he claimed to only have “two years and eight months” more education than non-optometrists, his understanding of what was needed to develop an efficient and finely tuned visual system was that of pure brilliance. The mark he left on Developmental Optometry is simply indelible.

Level Four – Clear and Blur at Will

Prior to my saunter into presbyopia, this was, by far, the toughest level to demonstrate to patients. Struggling with Accommodative Flexibility in my youth, I came to understand the meaning of visual stamina challenges first hand. The mechanisms and muscles at play here are so small, and yet it was not lost on me how much weight they must carry throughout our day.

Our setup for Level Four is the same as the previous levels – comfortably seated, Harmon’s distance, translucent patch, age appropriate sized font.

The initial instructional set includes placing the lens in front of the non-occluded eye and ask the patient to make the target clear. Hopefully, but this level of Mental Minus, both you and your patient are comfortable with choosing an appropriate power of lens for they can find success with some degree of effort. Unlike in previous levels, though, the patient is not going to remove the lens during this activity; instead, they should be asked to “let go” of their accommodation so the target becomes blurry again. When fully blurry, instruct the patient to clear the target. Rinse, lather, and repeat. The idea is to move accommodation from relaxation to stimulation repeatedly at will. An explanation that has offered me relative success with patients is to visualize a rubber band being repeatedly stretched to its limits and then slowly released, over and over again. This strength and stamina which is build up by repeated stimulation and relaxation of accommodation is what we are after.

For the Vision Therapist, observations might include constriction and relaxation of the pupil with relative fluidity, the occluded eye should be moving relative to the accommodative demand (stimulation of accommodation results in convergence and/or relaxation of accommodation results in divergence), and any mention of the SILO effects associated with the lens. In terms of discussion with the patient, this tends to be the level of Wachs Mental Minus where patients really discover feeling tone relative to where their accommodation is postured, so having that discussion seems to hold value, as well. As always, we want to repeat the activity with the other eye to ensure responses are equal.

From a purely subjective standpoint based on nothing more than my own experience with patients in the therapy room, this level tends to be such that patients need more time to feel successful. My sense is that all previous levels require reasonable effort to complete but their needed output seems to come in short bursts; conversely, this level requires effort over a sustained period of time making it a bit more intense for some, and requiring a more sustained level of control and strength than previous levels for most.

Not to be lost here is the need to build the patient’s awareness of what their eyes are doing. Questions like “do you feel your eyes changing?”, “what do your eyes feel like when you clear the lens versus letting things get blurry?”, and “does clearing this lens feel like anything else you have ever done with your eyes?”.

Remember, bringing a patient’s awareness to what they are doing and how they are doing it is key to their success. This level of understanding will help them to be successful with the activity, but more importantly, help them to take their newly discovered visual skills out into the real world as they find success.


As we round the bend in this sequence of activities, a few things come to me as important points to consider when working through Wachs Mental Minus; the first being hierarchy. For most patients, this sequence of accommodative challenges seems to be at the upper end of the hierarchy, meaning it may not be a “day one” activity. Not to suggest that it couldn’t be, but please consider the idea that there may be more appropriate activities for understanding feeling tone, accommodative posture, and SILO which would, in turn, serve as the foundation for the discussions involved with Wachs Mental Minus. The second thought is to consider the benefit of real space accommodation versus simulated space accommodation. In our everyday lives, we accommodate all day long through real space and whether we know it or not, we are constantly building, calibrating, and re-calibrating our sense of space and the associates spatial maps. Building these skills through simulated space (lenses) is great, but to truly achieve a skill that is owned, we need to make it real enough to use and transfer into their everyday life. Remember, also important here is the “Where Am I?” and the “Where Is It” challenges which are resolved through our manipulation and understanding of real space, so always consider incorporating aspects of real-space types of training into your Vision Therapy program. They, too, have incredible value.

Part Five – Clear – Remove Lens – Keep Blurred

Before you ask, let me say unequivocally “yes”, things just became much more difficult. For the first time in this sequence, feeling tone is the skill needed for a patient to find success with this activity. Without it, true success would seem to be rather difficult, if not impossible. So as a Vision Therapist, we need to feel confident our patients both understand feeling tone and are able to use and control it to accomplish some level of control with their accommodation prior to beginning this level.

Our setup for Level Five is unchanged – comfortably seated, Harmon’s distance, translucent patch, age appropriate sized font.

As an aside, if your session programming is such that this level is your first activity of the day, it may be advisable to briefly revisit one of the previous levels as a warmup as well as to review feeling tone within the accommodative system. This is done simply to help your patient to re-access their newly developed skills, as well as to feel and find success.

For the first step of this activity, the patient places the lens in front of the un-occluded eye (identical positioning as before) and works to clear the letters. Once the letters are clear, we usually will ask the patient to hold the lens in place and share feedback on what they are doing to accomplish clarity. Questions to consider might be:

  • How long did it take for the image to become clear?
  • What did you have to do/change to make the image clear?
  • Do you think you would be able to undo it (relax accommodation) if asked?
  • Are you able to describe the feeling associated with making the image clear?
  • If asked, do you think you might be able to recreate this feeling without the help of the lens?
  • How would you describe the level of difficulty?

There are many more ways, and many different ways, to communicate the emphasis of the activity. The overarching goal here is to build patient awareness of what they are doing to change the picture, to identify areas or skills they would like to change in order to make this a more smooth and accomplishable goal, and to build the knowledge that they are making the change, not the lens. All the lens does is create a visual conflict for them to resolve.

Once both you and the patient are confident they have a good understanding of what’s happening, they should be instructed to remove the lens while holding on to, or maintaining, their accommodative posture. Effectively, we are asking patients to be in control of the change that is occurring rather than allowing the lens to be the determining factor. After a few seconds, the lens can be placed in front of the eye once again. If this is done correctly, the patient should experience blur while the lens is not in front of their eye, and immediate clarity will be experienced when the lens is placed back in front of their eye.

As always, the Vision Therapist might want to observe pupil response, movement of the eye under the patch, and well as inquire about the patient’s current awareness of SILO. In my experience, this tends to be the level whereby patients will inadvertently alter their working distance, with most moving closer to the target making it appear larger, as a means for finding success. When this happens, usually a “did you change something?” is enough to call their awareness to the reduction in working distance, and almost invariably, they will self correct. As the activity is repeated with the other eye, any differences in performance and/or ability should be noted and addressed in future sessions.

The last piece of awareness that becomes important in this level is helping patients understand where they are looking in space. This is purely a Z-axis challenge. Bringing this concept into their awareness seems to help both with making the skill repeatable, but also helps with transferring the skill into their everyday life. For me, this is a “can you be aware of the changes in space?” question. How does the space change when you make the image clear through the lens? Do you need the lens to make that change or can you make it on your own? Can you use the spatial cues to make it happen more successfully? Even if your patients cannot articulate their answers well, you asking the question will help them to build the awareness and solidify the skill!


OK, friends. We are approaching the home stretch!

By this point in the sequence, hopefully we have a reasonable sense of our partient’s abilities. It is worth noting that in most cases, the seven levels of Mental Minus are not completed in one or even two sessions. My comfort level, and please alter anything I write to match your own model, has been to work through one or maybe two levels per week with corresponding home assignments as the patient’s performance dictates. A phrase Dr. Harry Wachs often used was ensuring the patient “owned the activity”, which for me is the key. Asking or assuming a patient can truly own an activity after 10-15 minutes of work seems to be a bit ambitious. If you consider it takes most toddlers several weeks to learn to walk efficiently at a time in human development when our brains are the most pliable, expecting an older child or an adult to own a new skill after one session to me seems a bit unrealistic. They may have a splinter skill to succeed at a particular level, but truly owning the skill means they should be able to perform the given task whenever and however they are presented a challenge, without obstacle or hesitation. For a parallel, think of walking. Most of us don’t sit in our chairs preparing to walk across the room by thinking “this time I’m going to put one foot in front of the other” – we just walk. We own the skill and can perform it without challenge at any time of the day or night. Owning visual skills should be treated with the same measurement.

Level Six – Blur – Insert Lens – Immediate Clarity

As mentioned in the previous levels, this level creates a fairly high visual demand for the patient, so it may be advisable to briefly review a previous level to allow the patient the opportunity to call up the skills needed to find success.

Our setup here is consistent with previous levels – comfortably seated, Harmon’s distance, translucent patch, age appropriate sized font.

To begin this activity, we ask the patient to place the lens in front of their non-occulded eye and clear the target while paying attention to the changes needed and the associated feeling tone. Once they have a good sense of this, the lens is removed and the patient should, again, clear the target.

Without placing the lens back in front of their open eye, the patient is asked to recreate the previously identified visual posture without the benefit of looking through the lens. If done well, the patient should report the target becomes blurry. For me, this tends to be a place where discussions of the Z-axis are important.

“Where are you looking?”

“How much closer/farther did you have to move your focus?”

“Does your visual space change when you work on this level?”

“Can you maintain complete awareness of the space between your eyes and the target? Including peripheral awareness?”

“Does your awareness of your visual space change (better or worse) as you work to reposture your focusing system?”

Once the patient has an increased level of awareness, the lens can be placed in front of their open eye. If they have achieved a successful visualization of where they were looking and how to revisit that posture on their own, the target will immediately appear clear in the lens.

As the Vision Therapist, when observing your patient work through this activity successfullly, you should observe none of the changes previously discussed. The addition of the lens should not create a pupillary response, nor should you be able to observe movement with the occluded eye.

Work at this level should continue until the patient can find and maintain proper visual alignment given the power of the lens being used. It is important to repeat this exercise with many individual powers of lens to ensure the patient truly understands how to move and hold their visual posture – effectively “owning” it.

As the Vision Therapist, if you need to troubleshoot when your patient is not finding success, here are a few suggestions:

  • Consider the skills needed for your patient to find success. If they are struggling, ask yourself if you have covered everything – feeling tone, spatial changes, SILO?
  • Does a different power of lens change the outcome for the patient. Although counterintuitive, less power is not always easier. Sometimes, bigger changes are easier to reproduce so higher powers are better. As your patient fine tunes their system, lower powers can be introduced.
  • Have we moved too fast? Please please please…don’t consider it a failure for you or your patient if you need to back up to a previous level. Sometimes review is what is needed to help a patient own a skill. There is nothing wrong with identifying the need to remediate. Remember, babies will fall down hundreds of times before they walk successfully, and sometimes crawling is just easier. Nothing wrong with it.
  • Consider peripheral awareness. Many times when patients are working hard on an activity, they tend to “look hard”, or visually tunnel. Although understandable, it’s not the most effective method. As they work on this level, remind your patients to find a balance between working intently and looking soft, with full peripheral awareness. Remember, the “Where Am I?” and the “Where Is It?” systems are still to be given full consideration here, even though we are not working on them directly.


As we make this last dash to the finish line of the Wachs Mental Minus series, a few important questions have been sent my way since starting this group of posts that need to be addressed:

If your patient is having trouble with one of the levels, is it wrong to move them back from the target so they have more room to work with?

To be clear, there doesn’t seem to be a right or wrong here. That is really the beauty of much of Dr. Harry Wachs’ contribution to the Vision Therapy world, very little of it lives in the sphere of ‘right or wrong’. Instead, it seems to be more of a ‘start where they are’ prospect, with the unspoken challenge to offer an appropriate increase or decrease in difficulty depending on the patient response. So, in short, as long as you know where the patient currently is and what steps you will take to help them find success, altering the specifics to match current ability levels seems just fine. After all, if there is one thing I know about Dr. Harry Wachs, it’s that he loved when doctors and vision therapists would think outside the box.

I am currently working on my COVT and am having trouble with the idea of different font sizes for different patients. Wouldn’t it be better if everyone worked with the same size letters to keep things consistent?

First of all, congratulations on your decision to complete your COVT! Surely, you will do very well!

In a perfect world, you are correct, consistency is best. The hard part is just as every patient is different so are their levels of ability. It would be hard to consider someone ‘incapable’ of finding success in this accommodative series simply over the size of the target, but that doesn’t make your point irrelevant. For me, every activity should have an attainable finish line, and if that means larger print, then so be it. The key is to note it and discuss the patient’s performance with your doctor afterwards, as my guess is, the two of you will find even more modifications to match your patient’s current skill level as well as new and creative ways to help them advance. At some point, those modifications may include smaller print.

You mention the “Where is It” circle often but I thought focusing was in the “What Is It?”. Can you explain that to me?

Thank you for asking this question. In some variation, I have received this question six times since posting Part One.

Yes, you are correct, for the most part, Accommodation is all about Identification – or the “What Is It?” circle. The piece to consider is what skills are needed to achieve successful accommodation? Some part of landing a clear target on our fovea has to be where in space to look. This becomes purely a Z-axis issue. If the object I am trying to clear is 10 feet away, and I adjust my focus so objects 30 feet away are clear, the original object at the 10 foot spot will be blurry. In order to make it clear, I need to know where it is in terms of distance from my fovea. By definition, this is a “Where Is It?” equation. Remember, though, everything affects everything. Even though we might be wearing a patch or perhaps are not trying to strengthen vergence with a given activity does not mean vergence isn’t active. Vergence and accommodation have a symbiotic relationship. Vergence (among other skills) is solving the “Where Is It?” challenge as a platform for accommodation solving the “What Is It?”.

The Finale – Bi-Ocular

Get rid of the patch, kids, things just got real.

To cover the technical – comfortably seated, Harmon’s distance, age appropriate sized font.

This level is the culmination of all skills covered in the Wachs Mental Minus series. To find success, our patients need to be able to call up each aspect gained in previous levels and bring them to the party. As the Vision Therapist, I myself feeling like a sports announcer offering a play-by-play to my patients as a means of coaching them through as they find success. You may find yourself needing to talk patients through this most advanced level.

In a comfortable posture, the patient holds the lens in front of one eye. Remember, both eyes are to remain open and gathering information. If done well, the patient should experience an overlapping of images – the smaller in the lens (assuming you are using a minus lens), and the larger through the eye without the lens. If your patient tends to suppress, we may need to find ways to help them keep both eyes seeking visual input. This may include moving their finger quickly in front of the suppressing eye, or even asking them if they can find ways to look more through their suppressing eye.

As an aside, I had a patient once who named each of her eyeballs, and when one wouldn’t cooperate, she would yell its name as loudly as she could and demand it worked harder. I don’t recall the names she chose, but do recall having a good laugh about it when she graduated as she shared one of her neighbors became concerned she was being attacked one afternoon and ran to her rescue. Good times!

With the eye looking through the lens, the patient should be instructed to clear and then blur the image. The image in the other eye is not to be cleared intentionally, and is only relevant as a means of suppression check. The image in the lens should be cleared and blurred repeatedly. As the Vision Therapist, we want to be watching for pupillary response as well as a vergence response from the eye not looking through the lens. These will be our best indicators of patient success. That, and the constant reporting of feeling tone from your patients, as by this level, feeling what is happening is a key component. If your patients experience SILO during this level of Wachs Mental Minus, even better. As always, this should be repeated with the other eye and performances compared. Ultimately, the patient should have the same experience with each eye.

Some ideas for making loading or unloading this activity might be changing your target size. Consider using a target that moves (Marsden Ball) as movement tends to help with the “Where Is It” challenge. It is also one of our monocular depth cues. Have the patient change their gravity by standing, walking, or even attempting these levels while on a balance board. Try different powers of lenses to work on JND’s. Or if your patient needs a much higher level of challenge, try having them wear binocular prism (low BI or BO) to add in a BOP and BIM component.

Wachs Mental Minus, as a series, is a very powerful accommodative challenge which seems to provide opportunities to challenge each skill area involved in efficient accommodation. As a Vision Therapist, if you have the framework of each level, and in the moment ask yourself “what skills are needed to find success?”, the benefits to your patients are inevitable.


3 thoughts on “Robert Nurisio, COVT, on Mental Minus

  1. Thank you for the exact description, step by step, so that you get an understanding of what mental minus can really do. Also, thank you for using my 4 Circles of Skeffington template from my website. Gladly anytime.

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