What is the appropriate length of a vision therapy program?
In my opinion, this can be the hardest question to answer as it is not always straightforward. Once you’ve completed your vision therapy work-up and know your patient needs vision therapy, you not only need to determine a type of treatment program, but the length of the program. In order to do so successfully, you must consider all of the diagnoses, and then consider other nuances that may change your course of treatment.
Below, you will find all of the critical elements I consider before making a recommendation on the length of a vision therapy program.
This is the easy part and is determined by your basic vision therapy workup that typically includes:
- Cover test (distance and near)
- NPC (accommodative vs. non-accommodative)
- In-phoropter phorias (distance and near)
- Vergence ranges (distance and near)
- Near Add (if necessary)
- Accommodative Amplitudes (minus lens)
- Vergence Facility
- Accommodative Facility (Mono/Binocular)
As well as your visual information processing (perceptual) portion of workup that typically includes:
- Oculomotor Function (DEM/Visagraph/King Devick)
- Visual Memory (simultaneous and sequential)
- Visual Motor Integration
- Visual Discrimination
- Visual Closure
- Form Constancy
- Screening for a possible reading disability
With the help of the Ultimate Guide to Vision Therapy Norms, you can determine what sort of binocular, accommodative or perceptual diagnoses your patient possesses.
2. The “Other Factors”
This is perhaps the most difficult piece to ‘learn,’ but some of the things I consider are:
- Maturity Level
- Developmental Delays/Missed Milestones
- Other diagnoses such as: Autism, PDD/NOS, Dyslexia, Post-Concussion, Psychological
The more vision therapy evaluations you perform, the more you’ll get a sense of the contributing factors that may affect how a person will respond/perform in therapy.
3. Science + Art: Determining the Number
If you use Clinical Management of Binocular Vision, by Scheiman and Wick, as a reference, they give you a criteria for determining the amount of sessions per binocular disorder. Most of the common binocular and accommodative disorders rank between 12-24 sessions depending on the severity. My method for compounding diagnoses are to determine the base number of sessions for the primary diagnosis, and then for each additional diagnosis, I will add 1/2 – 3/4 of the total recommended sessions. You have to remember that you will be addressing multiple binocular functions within each session, so you do not need the total amount for each diagnosis.
For example, your patient has a moderate convergence insufficiency, a mild accommodative insufficiency and a moderate oculomotor dysfunction. The base number of sessions for the CI would be 16, and then an additional 16 needed for the combination AI/OMD, for a total of 32 sessions. This might seem confusing, but you’ll get the hang of it!
My biggest piece of advice here is to have a conference with the parents a few days after the vision therapy work-up. This gives you time to consider all factors related to the case, write up a report and make a recommendation for the amount of vision therapy sessions with confidence. Some parents might push you to give them a ‘ballpark.’ I usually just respond by saying that I definitely think vision therapy is needed (if it is!), and that I need some time to look at all the pieces of the puzzle to ensure the program will meet the patient’s specific needs.
On a side note: Strabismus is an entirely different beast and is really case by case depending on many factors including frequency, size, the type, correspondence, etc… Because there are so many variables, it is hard to make a methodology for this group of patients. Consider all factors relating to your specific case and then determine from there what you want to do.
The typical session amounts that I prescribe are 12, 16, 24, 32 and 36. I find that the two end pieces here are the easiest to recommend: 12 for a straightforward case, 36 for a person who is a ‘visual disaster.’ The in-between session amounts are the ones that take a little bit of practice to get right. If you are between a number of sessions, I always recommend to err on the side of caution and prescribe more. It is much easier to tell a parent that their child did so well in therapy that they are going to finish a few sessions early, rather than to try and tack on more sessions at the end. If you are really unsure of a case, recommend a trial of 12 sessions, and see how the patient responds. At the re-evaluation, you’ll be able to determine how much progress was made and from there, you can determine the remaining course of therapy.
What I can tell you is that the mastering of prescribing a vision therapy program takes time and practice, but is an essential part to guarantee your success.
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