Vision Training Instruments

Vision training equipment ranges from a block letter chart pasted on a simple Popsicle stick to an elaborate rotation trainer costing thousands of dollars. Vision training equipment is used to enhance visual comfort, ease and efficiency. Training programs can also alter how a patient processes or interprets visual information. Vision training is typically done under the supervision of an optometrist or other eye care professional.

Three Main Vision Problems

• Ocular motor dysfunction, accommodative dysfunction and binocular fusion dysfunction are the three main types of problems that are addressed through vision training. Ocular motor dysfunction is characterized by poor eye movement control, erratic accommodation and unsteady fixation. Inadequate perceptual motor and visual motor integration can also be present. Accommodative dysfunction is difficulty with one's ability to change the eye's focus to see objects at different distances. Binocular fusion dysfunction is difficulty with converging the eyes, or turning them inward, and divergence of the eyes, moving them outward. Some vision training equipment will overlap in targeting each of these three areas.

Ocular Motor Vision Training Instruments

• Rotator: A rotating disk used to train eye hand coordination. The rotator can be on a stand or table. It can be varied in speed and direction to increase the challenge.

  Tachistoscope: An electronic device that flashes an image for a brief period of time. The tachistoscope is used to train the eyes to work together.

  Visual Tracking Books: Workbooks that contain pages of ocular mazes. The mazes are used to develop smooth continuous eye movements.

  Marsden Ball: A spongy ball on a string imprinted with letters. It is used to improve visual perception and visual motor skills, eye--hand coordination, tracking, discrimination, visual memory and spatial orientation.

Accommodative Dysfunction Vision Training Instruments

• Flippers: Plastic holder with four lenses of two different strengths. Used to improve the focusing flexibility of the eyes.

  Hart Charts: Each hart chart is a set of two cards, each displaying 10 columns and 10 rows of letters. One of the cards is in a smaller font and is handheld. The other is put up on a wall at least 6 feet away from the patient. The patient practices shifting focus from distant to near.

  Stereoscope: An instrument with binocular eyepieces in which the patient looks inside to view two slides of the same object. One slide is viewed by the right eye and one slide is viewed by the left eye. It is used to train binocular accommodative flexibility.

Fusional Dysfunction Vision Training Instruments

• Cheiroscopic Drawings: Tracings done at a subjective angle to train the patient to use both eyes and to not suppress the nondominant eye.

  Polaroid Vectograms: Two transparent cards, each with the same image; the right eye sees one card and the left eye sees the other through polarized lenses. When both eyes are working together, the image is seen three-dimensionally. The range of convergence and divergence of the eyes is strengthened.

  Stereoscope: Defined above; when training fusional problems the stereoscope is used specifically for suppression elimination, simultaneous vision training, and to eliminate anomalous retinal correspondence.

  Brock String: A 10--20 foot piece of string with three colored balls each separated by 12 inches. The most common problem that is worked on with the Brock string is convergence insufficiency, or difficulty focusing the eyes together at near distances.