Red-red rock is an example of an anaglyphic procedure whose objectives are to improve accommodative amplitude and facility. Although both eyes are open for this task, the conditions are not truly binocular because central fusion is not possible; thus, it is referred to as a biocular task. Red/green glasses are placed before the eyes, and because of the nature of the targets, neither eye can see both targets.

The setup for this procedure is illustrated in Figure 7.1A. The therapist selects white tiles and a matching red transparent slide with black lettering. The tiles and slide are shown in Figure 7.1B. The red transparent slide with black lettering is attached to the rear-illuminated screen of a cheiroscope. The patient wears red/green glasses with the red lens over his or her right eye and the green lens over the left. Give the patient a set of white tiles that have words printed on them in red. On the transparent red slide (40 cm in front of the patient), these same words appear in black lettering. The eye with the red lens sees only the words on the red slide, whereas the eye with the green lens sees only the words on the white opaque tiles. The patient looks at the first white tile and clears the print (eye with green lens) in order to identify the word that must be found on the red slide. The patient then tries to find the matching word on the red slide. To do so, the patient must use his or her right eye with the red filter. Thus, although both eyes are open, central fusion is not possible. Rather, to perform the task, the patient alternates from the right to the left eye.

The addition of clip-on lenses over the red/green glasses introduces the accommodative component to the task. A plus lens is placed before the right eye and a minus lens before the left. As the patient shifts from the tiles to the red slide and back to the next tile, he or she must alternately inhibit and stimulate accommodation. The power of these lenses is increased in small increments, until the patient can perform the task through +2.50 and −6.00.

Important factors to consider and methods of increasing and decreasing the level of the task are listed in Tables 7.1 and 7.2.

For patients younger than 20 years, discontinue this therapy technique when the patient is able to successfully clear +2.50 and −6.00, 20 cpm. For patients older than 20 years, the endpoint depends on the amplitude of accommodation. Discontinue this procedure when the patient is able to clear minus lenses equal to one half the amplitude of accommodation.

The objective of this procedure is to improve accommodative amplitude and facility. Although both eyes are open for this task, this procedure is designed as a biocular task. Liquid crystal glasses are used, and neither eye can see both targets. Thus, it is a technique designed to improve the monocular accommodative amplitude and facility.

The computer program presents four boxes with the letter “C” inside. Only the right eye first views the stimulus. The letter “C” is randomly pointing up, down, left, or right. The patient is instructed to move the game pad switch in the direction in which the letter “C” is pointing for each box, starting from left to right. Correct responses result in a “beep” tone, and incorrect responses in a “boop” tone. After all responses are made to the first four boxes, a second set of boxes appears; these are seen only by the left eye. While the patient is viewing the targets, accommodative flippers (supplied with the software) are held before the patient’s eyes. One eye views the target through a minus lens, whereas the other views the target through a plus lens. For example, the level 1 accommodative flipper has a +0.75 D lens before one eye and a −1.50 D lens before the other eye, whereas the level 6 accommodative flipper has a +2.50 D lens and a −5.00 D lens.

For patients younger than 20 years, the endpoint is completing the program using the level 6 accommodative flippers.

Lens sorting is a monocular accommodative technique designed to develop an awareness of the ability to relax and stimulate accommodation. A second objective is to teach the patient to voluntarily accommodate or relax accommodation.

The actual lenses used for this procedure depend on the age of the patient. In all instances, care should be taken to select minus lenses that are less than one half of the patient’s amplitude of accommodation. When working with a 30-year-old patient with an amplitude of accommodation equal to 8 D, the highest minus
lens used would be 4 D. For the next example, we assume the patient is younger than 20 years. With one eye occluded, the patient is instructed to view age-appropriate reading material with about 20/30-size print. A moderate-power minus lens (−3.00 to −5.00) is placed before the patient’s right eye, and he or she is asked to clear the print. The minus lens is removed and is replaced by a low plus lens (+1.00 to +1.50). The patient is again asked to clear the print through the plus lens.

After repeating this several times, the patient is asked to describe the differences he or she experiences through the minus and plus lenses. The questions should be open-ended initially. If the patient is unable to describe any differences, ask the following questions:

The objective is for the patient to realize that he or she can either stimulate or relax the accommodative system and learn to do this voluntarily. Any other questions that will lead the patient to this objective would be appropriate.

Once the patient can consistently describe that the print becomes smaller with the minus lenses and appears either closer or farther away, the second objective is to help the patient develop a kinesthetic awareness of accommodation. We want the patient to be able to appreciate the difference in feeling between relaxing and stimulating accommodation. Often it is necessary to ask specific questions and spend some time explaining what the patient is experiencing. The following is an example of such an explanation: “Does it feel like you are working harder or straining your eyes now? That is the feeling of focusing. If you cannot see clearly through this lens, try to get the feeling of straining, looking close, or focusing your eyes.” (Conversely, with plus lenses you would ask the patient to get the feeling of looking far away, relaxing the eyes, or drifting off to sleep.)