Vision therapy requires a commitment to each patient’s visual health

For optometrists who practice vision therapy, the commitment to each patient in terms of time and hands-on instruction is much more extensive than in traditional optometry. However, for those who work in this field, the rewards are well worth the effort.

“It’s a whole different type of practice; it involves an ongoing relationship,” said Nancy Torgerson, OD, FCOVD, a vision therapy practitioner based in Lynnwood, Wash. “It is a huge endeavor, and it is not a one-time yearly evaluation. Not only is there more relationship-building with patients and parents, but also with other professionals and colleagues. It is important work.”

Convergence insufficiency

One of the most common visual disorders treated by vision therapy is convergence insufficiency. The primary manifestation of this disorder is a significant exophoria at near along with reduced compensating convergence abilities.

According to Michael Zost, OD, FCOVD, FAAO, a practitioner based in Glenview, Ill., diagnosis of convergence insufficiency begins with standard optometric techniques, including phoria measurements and vergence assessment at far and near along with examining accommodation, he said.

Dr. Zost added that he takes the patient’s test results, analyzes them against normative values, and determines if the patient’s visual profile matches that of a convergence insufficiency case. “The pattern of results for a patient with convergence insufficiency is easy to diagnose as long as you evaluate the visual system adequately,” he said. One other test result, which shouldn’t be left out, is determining the AC/A ratio. This looks at how well people adjust their eye alignment and coordination as they change their focus. “It’s critical for determining if you really have a convergence insufficiency case or some other binocular vision disorder.”

Dr. Zost said common symptoms of convergence insufficiency may include double or blurry vision, reporting that words appear to jump or move, and avoidance of close work.

According to Kenneth Lane, OD, FCOVD, a vision therapy practitioner in Lewisville, Texas, convergence insufficiency can be detected through near and far phoria measurements.

“Convergence insufficiency is the difference between the near and far phoria,” he said. “If there is a difference of 7 PD or more and there is more exo at the near point than the far point, then there is convergence insufficiency.”

In terms of treatment, Dr. Zost said, in many cases, he will treat focusing prior to addressing the convergence issue. “This indirectly helps out with convergence and ensures that the therapy for convergence treatment in office might include using vectograms, anaglyph slides or aperture rule,” he said. However, he notes the the lions-share of treatment occurs at home with patients using less sophisticated equipment such as Brock’s string, eccentric circles and “lifesaver cards.”

Dr. Zost said using Brock’s string helps patients develop binocular coordination, specifically convergence with accommodation. In addition, he uses “lifesaver cards” and other tools.

Dr. Lane said he would treat convergence insufficiency with convergence training and base-out range training.

Dr. Torgerson said disorders such as convergence insufficiency are part of a larger problem that must be addressed. “Convergence insufficiency, accommodative infacility and convergence excess are just symptoms indicating that the brain and eye do not know how to process visual information,” she said. “We want to get up to what we expect in all of these areas as far as fuse induction and flexibility.”

Accommodative infacility

Accommodative infacility is another common clinical problem specific to focusing ability. Patients with this visual disorder usually have a greatly decreased response to ±2-D flipper facility testing.

“With accommodative infacility, we are looking at how flexible a patient’s focusing is and how quickly he or she can change focus,” Dr. Zost said. “So there are a few different tests that consider how well patients can relax focus and, on the other hand, how well they can stimulate focus.”

Dr. Zost said he begins to suspect accommodative infacility when patients show a delay of focus from near to far or far to near.

“This may occur especially after near work and, specifically, computer or video game use,” he said. “In addition, these patients may experience a dull frontal headache that begins after near work and goes away only when they stop the close work or go to sleep.”

Dr. Zost said the use of lens flippers can help determine how quickly patients can change focus.

Dr. Lane said vision therapy is appropriate treatment for accommodative infacility. “Accommodative infacility applies to anybody who has low-positive relative accommodation at the near point,” he said. “We would put the patient in vision therapy and do a lot of minus work.”

Dr. Zost said accommodative infacility is one of the easiest conditions to treat with vision therapy. “To treat this condition, we use some of the same techniques that we used for testing,” he said. “It’s usually best to treat one eye at a time, before treating the eyes together. Doing it this way will give the patient a much better end result in less overall time.”

He said treating accommodative infacility involves the use of a +/- lens flipper, which is used to alternate between focusing harder and then relaxing focus as quickly as possible. This exercise is done while reading for 10 to 15 minutes per eye for 1 to 2 weeks, Dr. Zost said.

“A primary care optometrist can prescribe this simple exercise to loosen up and improve focusing on a great number of patients younger than 40,” he said. “The flippers sell for about $20 to $25 and can be purchased from an optical supply company.”

Convergence excess

Convergence excess, according to Dr. Zost, is one of the most difficult conditions to treat with vision therapy. In this condition, the patient’s eyes have a tendency to aim closer than the object the patient is trying to see. It is possible to achieve correct aim only by applying extra effort.

“In convergence excess, a person’s eyes, especially when looking up-close, will have a tendency to over-converge,” he said. “This is the opposite of convergence insufficiency, where a person’s eyes actually have a tendency to drift apart. In both cases, the eyes are fairly straight when they are far away, but up close, things change.”

Dr. Zost said convergence excess is characterized by esophoria, which is a challenge to treat in vision therapy. “We have to teach the patient how to diverge his or her eyes, which is much more challenging to do,” he said. “Sometimes, again, we will use Brock’s string, or other exercises, as well as glasses for reading up-close to take the strain off the eyes.”

According to Dr. Zost, patients with convergence excess may show symptoms such as double vision, eye strain, blur at near, temporal headache and words jumping or moving.

Dr. Lane said convergence excess would pertain to any esodeviation at the near phoria. “You would diagnose patients through a regular vision exam, when taking the near and far phoria measurements,” he said. “And I also look for complaints from patients and symptoms of eye strain.”

He said convergence excess is usually treated by either a plus lens or vision therapy. “In vision therapy for convergence excess, we would treat with lots of plus lenses and base-in fusional training,” he said.

Types of vision therapy practices

Vision therapy practices are distinctly different from the typical optometry practice, and there is additional variation within this subgroup.

“My practice is different from a lot of others. Approximately 95% of the people I see have learning disabilities,” Dr. Lane said. “We don’t see too many strabismus patients. So when I check a child for learning disabilities, if he or she has oculomotor problems and accommodation or convergence problems, I treat them all through the vision training program at the same time.”

While he diagnoses patients for vision therapy, Dr. Lane said, “I don’t do the therapy myself – I train teachers to do it. I find that teachers work better with children.”

Dr. Lane said the teachers he has trained to treat vision therapy patients are very effective in working with the children. “To keep a child in vision therapy, you must keep the child happy,” he said.

In Dr. Torgerson’s practice, eight vision therapists work under her guidance. She said she holds vision therapy workshops to educate parents and teachers.

“In the office, once a month, we have parent-teacher workshops, and we go over how vision affects learning,” she said. “Usually, people think in terms of 20/20; they don’t think about how this could have anything to do with having trouble with reading, hitting a baseball, driving a car or getting a headache.”

She said, although treating patients with vision therapy can be an extensive process, it is very gratifying as well. “It’s a fun way to practice,” she said. “You get the joy of the successes and the changes in people’s lives.”

For Your Information:

• Nancy Torgerson, OD, FCOVD, is a vision therapy practitioner located in Lynnwood, Wash. She can be reached at 18631 Alderwood Mall Pkwy #201, Lynnwood, WA 98037; (425) 771-5113; e-mail: nancyt@nwlink.com.
• Michael Zost, OD, FCOVD, FAAO, is a vision therapy optometrist practicing in Glenview, Ill. He can be reached at 1920 Waukegan Road, Glenville, IL 60025; (847) 657-8787; fax: (847) 657-8730; e-mail: mzost@earthlink.net.
• Kenneth Lane, OD, FCOVD, a vision therapy specialist, can be reached at 230 W. Main St., Lewisville, TX 75057; (972) 221-2564; fax: (972) 436-7964.