Tests to Treat Patients with Accommodative Abnormalities

By Lipsa Jiegney Udwadia

and student of the Expert Certificate in Vision Therapy

From a developmental and behavioural perspective, few tests related to accommodative abnormalities:

 

  • Anaglyphs, Polaroids and Liquid Crystal Filters:

 

RED-RED Rock: 

 

Objectives: To improve accommodative amplitude and facility.

Equipment needed: Cheiroscope with red-red rock attachment, red-red rock tiles, red/green glasses, halberg-type clips, trial lenses.

Working distance: 40 cm.

Description and set up:

  • The therapist selects white tiles and a matching red transparent slide with black lettering. 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.
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  • Give the patient a set of white tiles that have words printed on them in red. On the transparent red slide (40cm in front of the patient), these same words appear in black lettering.
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  • 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.
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  • 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, both eyes are open and central fusion is not possible.
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  • 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.
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  • End Point: Age<= 20:Patient should be able to perform task with +2.50 and -6.00 Ds and Age >= 20 half of the amplitude should be an end point.
  • Level 1: Ask the patient to complete task with no time consideration.We can alternately change plus and minus lenses before the eyes from visit to visit.
  • Level 2: To increase the level of difficulty of the task,add the variable of time.
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  • Computer Orthoptics VTS3-4 Liquid CrystalSystem:

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Accommodative Program:

 

Objectives: To improve accommodative amplitude and facility.

Equipment needed: Computer orthoptics vts 3-4,liquid crystal glasses,computer orthoptics flippers A, B, and C.

Working Distance: 40 cm.

Description and set up:

  • The computer program presents four boxes with the letter “C” inside.
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  • Only the right eye first views the stimulus. The letter “C” is randomly pointing up, down, right or left. 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.
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  • Correct responses result in a “beep” tone, and incorrect responses in a “boop” tone. After all the responses are made to the first four boxes, a second set of boxes appears; these are seen only with the left eye.
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  • While the patient is viewing the targets, accommodative flippers are held before the patient’s eyes. One eye views the target through a minus lens and other views the target through a plus lens.
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  • End point: patients younger than 20 years old should be able to perform the test through level 6 accommodative flippers.
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  • Note: Level 1 to 6 accommodative flippers come with the software.
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  • Lenses, Prisms, and Mirrors:

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Lens sorting (Monocular):

 

Objectives: (1) To develop an awareness of the ability to relax and stimulate accommodation. (2) To teach the patient to voluntarily accommodate or relax accommodation.

Equipment needed: Loose uncut lenses, Accommodative Hopping cards,

Accommodative rock cards or other age appropriate reading material in variousprint sizes from 20/80 to 20/30, eye patch.

Working distance: 40 cm.

Description and set up:

  • The actual lens selected to stimulate or relax the accommodation will depend upon the age of the patient. Special care should be taken when selecting minus lenses.It should not be more than half of the amplitude for the individual patient.
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  • End point: Patient can either stimulate or relax the accommodation and learn to do this voluntarily.
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  • Loose lens rock (Monocular):

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Objectives: To restore normal accommodative amplitude and facility.

Equipment needed: Age appropriate reading material of varying print sizes from 20/80 to 20/30, uncut plastic lens blanks from -6.0 to +2.50, in 0.25 d increments, accommodative hopping cards, eye patch.

Working distance: 40 cm.

Description and set up:

  • Level 1: Occlude the patient’s left eye and ask him or her to follow instructions on the accommodative hopping cards held at 40 cm through the plus and minus lenses that are alternately held in front of his or her eye and patient is asked to clear the target.
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  • Level 2: Patient is asked to regain clarity as quickly as possible and compete the task.
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  • End point: Patient should be able to achieve the value of half of the amplitude of accommodation as per his/her age specially for adults >20 years of age. For youngsters, they will be expected to achieve +2.50 to -6.0 D with speed.
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  • Binocular loose lens rock:

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Objectives: To restore normal accommodative amplitude and facility while eliminating suppression.

Working distance: 40 cm.

Equipment needed: Accommodative hopping cards, or other age-appropriate reading material of varying print sizes from 20/80 to 20/30, uncut plastic lens blanks from -6.00 to +2.50 in 0.25 D increments, halberg clips, 6 Δ loose prism.

Description and set up:

  • Level 1: Ask the patient to wear trail frame and add 6 Δ vertical prism in front of one eye to dissociate the two eyes. Or if patient is wearing glasses halberg clip can be attached to the patient’s glasses and prism can be added in that.
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  • After adding a vertical prism low plus lenses and low minus lenses are added in front of the right eye and left eye respectively. Patient is asked to clear the lower target first and after reading it he/she can be able to read the upper target clearly.
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  • This procedure is repeated in frequent visits until the patient is able to clear with +2.50 to -6.00 D or half of the amplitude for the patient’s age.
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  • Level 2: Now ask the patient to read with clarity as fast as possible and power is increased gradually from low power.
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  • End point: +2.50 to -6.0 D, 20 cpm (cycles/minute).
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  • Binocular Accommodative facility (BAF):

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Objectives: To decrease the latency and increase the speed of the accommodative response under binocular conditions.

Equipment needed: Flippers ranges from ± 0.50 to ± 2.50 in 0.25 D increasing steps and accommodative hopping cards, age appropriate reading material, polaroid or red/green bar reader, red/green glasses and any binocular vision target such as vectograms, tranaglyphs, the aperture rule, eccentric circles or free space fusion cards.

Description and set up:

  • An age appropriate reading material like 20/30size print bar reader is placed and then the patient wears red/green glasses and then over that ±50 flipper is being placed. Afterwards, the patient is asked to clear the target and after learning to clear he or she should be able to identify that with plus lenses the letters become bigger and with minus lenses the letters become smaller. Also, if there is any eye strain that should be reported.
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  • Once the patient can do this with the±50 D flipper we can move to higher power flippers gradually.

End point: The patient should be able to clear up to ± 2.50 D flippers, 20 cpm

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