Considering how much we write about amblyopia and strabismus, the question posed on our blog was fair enough: Is there any research about the efficacy of vision therapy for an adult who has both amblyopia and strabismus?
I gave the commenter a link to our report on amblyopia, but he was looking for more details. He wanted specific examples of how vision therapy can help a person suffering from both amblyopia and strabismus, otherwise he would have to assume that what his ophthalmologist had told him was true: Vision therapy wouldn’t work in adults with strabismus and amblyopia.
I posed the question to Dr. Kellye Knueppel of The Vision Therapy Center, and her response made me realize that this would involve more than finding a quick link to some research.
“What kind of strabismus does he have?” she asked. “There are over 30 different types of strabismus.”
I didn’t realize this. Dr. Knueppel continued to ask questions. Does his eye turn in? Does it turn out? Does the eye turn alternate between the two eyes? Is it intermittent or constant? Does it turn more when he looks up or when he looks down? Does he have a problem with one of the muscles when it moves in a certain way?
“I don’t mean to ask all this, because it sounds like I’m evading the question,” she said. “But to provide him with an accurate answer, however, I have to know this information.”
Dr. Knueppel’s questions didn’t end there. She also needed to know about his amblyopia. Was it from a refractive condition? How long had he had it? Had he patched for a period of time?
Again, after another round of questions, she sighed. “You’re starting to see the difficulty of finding a gold-standard study for his question. There are just so many variables involved.”
It’s much easier to do a double-blind study on a medication, Dr. Knueppel elaborated. For blood pressure medication, for example, you have two groups. One takes the medication and one doesn’t. You monitor the response, and you have yourself a tidy little study.
Creating a double-blind, randomized clinical study to determine the efficacy of vision therapy for an adult with strabismus and amblyopia is next to impossible, because of the unique nature of each case. It’s very difficult to find a large enough pool of patients who have the exact same kind of strabismus, much less strabismus and amblyopia.
Are there double-blind studies for strabismus surgery?
Our blog commenter’s ophthalmologist cites a lack of clinical evidence for vision therapy. I could understand Dr. Knueppel’s frustration with the blog commenter’s question. Dr. Knueppel and The Vision Therapy Center have helped over 2,000 patients with vision therapy, and have many clinical success stories.
However, because of the circumstances involved with each case, it’s nearly impossible to produce the gold-standard double-blind tests that seem to be considered the only proof of success.
The efficacy of vision therapy for non-strabismic vision problems is easier to determine with large, double-blind and randomized studies. In 2008, the Convergence Insufficiency Treatment Trial (CITT) found that approximately 75 percent of those who received in-office therapy by a trained therapist plus at-home treatment reported fewer and less severe symptoms related to reading and other near work after the office-based vision therapy.
This was a randomized, double-blind, multi-center trial; the combination of all three qualities added to the study’s objectivity. However, convergence insufficiency tends to have fewer variations in clinical findings than strabismus, making it more feasible for such a study to be conducted.
Research does exist on the efficacy of vision therapy for strabismus and amblyopia – just none to our knowledge of the two conditions together. Dr. Knueppel told me that during her residency, she read more than 70 papers on strabismus. Would this patient want to trudge through all of them to try and find specific information on his condition? Probably not. And, besides, that’s the doctor’s job.
So what would a scientist do if confronted by the blog commenter’s dilemma?
In the case of Dr. Sue Barry, we have an answer. Dr. Barry, a neuroscientist, suffered from strabismus. Her landmark book Fixing My Gaze is an amazing compilation of research, presented in the context of her own story.
Dr. Barry approached vision therapy asking the same questions as our blog commenter. Why did she try? One, she found enough research and met with enough trained and credible optometrists to see this wasn’t a snake-oil sale. And two, since nothing had worked in the past, vision therapy seemed like the next logical option. If you asked her, she’d likely wished she started with vision therapy first, as it helped her overcome her vision problems.
In life, we all want absolutes. We want definitive answers, knowing with 100% certainty that what we’re about to embark on will work, guaranteed.
That’s usually not the case in medicine, and yet it doesn’t stop people from pursuing “off-label” uses of medicine. Off-label use occurs when a pharmaceutical is prescribed for a condition, population or dosage level different than what the FDA approved.
According to a 2006 publication from the Archives of Internal Medicine, “Up to one-fifth of all drugs are prescribed off-label.” Using vision therapy for the treatment of amblyopia and strabismus could be thought of as an off-label treatment – we’ve had proven success for each condition, so the blog commenter might consider pursuing it despite the lack of specific, evidence-based research.
That was my family’s approach when we put our daughter through vision therapy. We looked for what research existed. We talked to parents that had been through the same issues. We read as much as we could on the subject.
Then we moved forward, and tried the therapy. It worked.
Sometimes, that’s what it comes down to. You’re never going to be 100% certain, no matter how many facts, figures and research are sitting in front of your face. However, you can draw reasonable conclusions and move forward based on the evidence at hand.
We wish our commenter well, and we’re sorry that we weren’t able to find more research for him. We hope that his doctor will be able to accurately diagnose his condition, and that his therapy will prove effective. Here are some videos on vision therapy success stories. We hope it makes his decision easier.