Vision therapy - also called vision training - is the non-surgical treatment of binocular vision disorders.  It involves the prescription of specific visual activities (performed with or without special lenses) to improve eye alignment or visual skills that have not developed properly.

Examples of binocular vision disorders include focusing problems, eye alignment problems, and inaccurate eye movements.  Amblyopia (also called lazy eye) is also treated with vision therapy. 

Though usually prescribed for children, vision therapy can also improve the visual skills of adults in some cases.

Refractive Errors vs. Binocular Vision Disorders

Doing a routine eye exam, your eye doctor evaluates (among other things) your visual acuity and determines if you need prescription lenses to correct a refractive error - nearsightedness, farsightedness, or astigmatism. 

For most school-aged children who have vision problems, eyeglasses or contact lenses are  sufficient to give them clear, comfortable vision.  But it's estimated that 20 percent of school-aged children have binocular vision problems that cannot be corrected with eyeglasses or contact lenses alone. 

Some of these disorders include:

• Convergence insufficiency - The inability to comfortably keep the eyes in a converged position when reading and focusing on things up close.

• Accommodative insufficiency - The inability to comfortably sustain adequate focusing power when reading or looking at close objects.

• Accommodative infacility - The inability to quickly and accurately change focus from far to near and back again (a skill needed to copy notes from a chalkboard).

• Vergence infacility - The inability to maintain accurate and comfortable alignment of the eyes when changing focus from far to near and back again.

• Eye movement disorders - The inability to move the eyes quickly and accurately from word to word on a page, or the inability to smoothly follow a moving object with the eyes.

If your child continues to experience eyestrain and headaches at school after a routine exam has been performed and eyeglasses have been prescribed and worn (if needed), consider seeking the services of an optometrist who specializes in vision therapy for a binocular vision evaluation.

Binocular Vision Evaluation

A binocular vision evaluation includes a number of visual skills tests that are not typically performed during a routine eye exam.  These tests may include:

• Eye alignment testing - Though basic eye alignment testing is performed during a routine eye exam, a vision therapy specialist may perform additional tests to determine how easily your child can maintain proper eye alignment and whether they are likely to experience eye fatigue because of a difficulty in maintaining eye alignment during reading and other near vision tasks.

• Eye focusing tests - To evaluate how easily your child can change focus and whether they are likely to experience eye fatigue, blurred vision, or reading problems from inadequate focusing skills.

• Eye movement tests - To evaluate the accuracy and speed of eye movements during simulated reading tasks to determine if poor eye movement skills may be contributing to a reading problem.

• Eye teaming tests - To evaluate how well your child's eyes work together as a team for a variety of visual tasks involving changes in eye alignment, focusing, and positioning.

The vision therapist will then compare your child's visual skills test performance to established norms for children of the same age.  If one or more visual skills appear to be deficient, a program of vision therapy may be prescribed.  

Vision Therapy Programs

The basis for vision therapy is the belief that visual skills can be improved with properly designed visual tasks (sometimes called eye exercises), in much the same way that the strength and coordination of a weak muscle can be improved with appropriate training. 

A vision therapy program usually consists of a combination of weekly one-on-one therapy sessions in the doctor's office and daily activities to be performed at home.  Special lenses and computer programs may be used as part of a vision therapy program to help improve visual skills.

Depending on the nature and severity of the visual skills deficiency being treated, a vision therapy program can last from several weeks to several months.

Vision Therapy vs. Orthoptics

Vision therapy is promoted by many optometrists, but it has its critics - especially among ophthalmologists.  Some ophthalmologists feel optometrists prescribe vision therapy unnecessarily, and that claims made by some optometrists that vision therapy is helpful in treating reading disorders and learning problems are false and misleading. 

Still, some ophthalmologists recommend a similar therapy called orthoptics to treat certain binocular vision disorders caused by an imbalance in the muscles that surround the eyes.  Orthoptics is usually administered by an orthoptist who has been certified to provide the service but is not a medical doctor.

Orthoptics is similar to optometric vision therapy in that it is non-surgical and involves eye exercises.  But orthoptics is generally prescribed for a more limited range of binocular vision disorders - mainly convergence insufficiency and mild misalignment problems.