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Sensory Evaluation: Stereopsis & Worth Four Dot Test

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24 Questions

What is the primary purpose of the Broad H test?

To test how well the eyes work together

What is the recommended testing distance for the Broad H test?

40cm

What is being tested during the NSUCO test of fixation, pursuits, and saccades?

Pursuit eye movements

What is the purpose of removing spectacle correction prior to the Broad H test?

To obtain accurate results

What is being assessed during the Worth Dot test?

Binocular vision

Why is it important to steady the child's head during the Broad H test in children?

To prevent head movement

What is being tested during the saccades testing?

Eye movement coordination

What is the primary purpose of the NSUCO test?

To evaluate sensory motor function

What is the main purpose of the Titmus Stereo or Stereo Fly Test?

To assess how well the eyes work together in seeing depth and 3D images

What type of images are used in the Randot test?

Polarised 3D images

What is the purpose of the Suppression Test in the Titmus Stereo or Stereo Fly Test?

To detect suppression in one eye

What is the minimum level of disparity tested in the Gross Stereopsis test?

250 arc sec

What is the result if a patient fails to detect the 'R' letter in the Suppression Test?

Suppression of the right eye

What is the purpose of the Stereo Fly Test?

To test for gross stereopsis in young children

At what distance is the Randot test typically performed?

40cm

What is the purpose of reversing the polarising lenses in the Randot test?

To change the disparities

What is the range of disparities presented in the Wirth Circles Test?

800” to 40”

What is the main purpose of the Wirth Circles Test?

To test fine depth discrimination

Why is the Wirth Circles Test unreliable as a screening test for gross anomalies?

Because it does not provide accurate results unless clinical judgements are made using circles 5 or 6-9

What is the disadvantage of the Titmus stereotest?

The displacement of some disparate circles seen monocularly provides a possible clue for the patient

How can the Titmus stereotest be modified to make it more challenging?

By increasing the viewing distance

What is the correct way to perform the Wirth Circles Test?

With the polarised spectacles worn, and the test plate held upright

What is the purpose of re-testing with the original orientation in the Titmus stereotest?

To check if the patient's performance is improved with reversed disparity

What is the importance of full light illumination during the Wirth Circles Test?

To ensure accurate results

Study Notes

Sensory Evaluation

  • Stereopsis is a test that measures how well the eyes work together to see depth and 3D images
  • The Titmus Stereo or Stereo Fly Test is used to overcome the problem of monocular clues
  • The test is performed at 40cm with the habitual correction or best corrected visual acuity and polarized glasses worn over the refractive correction
  • The test comprises of a suppression test, stereo fly, animal stereo, and circles stereo test

Suppression Test

  • The test displays "R" and "L" letters, which are only visible to the right and left eye respectively
  • Failure to detect "L" indicates suppression of the left eye, while failure to detect "R" indicates suppression of the right eye

Gross Stereopsis

  • The test uses random dot patterns to test two levels of disparity: 500 and 250 arc sec
  • The patient is required to identify shapes or letters in the squares

Stereo Fly Test

  • The test is useful for young children, who respond behaviorally if the fly is seen in 3D
  • Pinching the wings above the plane of the picture indicates the presence of gross stereopsis of 3552 arc sec
  • Pinching against the flat surface indicates absence of gross stereopsis

Animal Stereo Test

  • The test has three levels of testing for young children, with disparities of 400, 200, and 100 arc sec
  • The test is performed at 40cm

Circles Stereo Test (Wirth Test)

  • The test presents disparities from 800" to 40" at 40cm
  • A monocular patient can use lateral displacement to give a correct response
  • The test is unreliable as a screening test for gross anomalies, unless clinical judgments are made using circles 5 or 6-9

Standard Procedure

  • The test is performed with polarized spectacles worn, and disparities in the animals test and circles test are all crossed
  • The Titmus test can be reversed by having the subject wear the spectacles upside down or by holding the book upside down

Extraocular Motility, Saccades, and Pursuits

Broad H Test

  • The test is used to assess how well the eyes work together
  • The test is performed at 40cm, and the patient is instructed to keep their head still and focus on a pen torch moved up, down, left, and right
  • The test is used to assess ocular motility and identifies underaction or overaction of yoke muscles

This quiz assesses the Worth Four Dot Test and Stereopsis, measuring how well your eyes work together to see depth and 3D images. It includes tests like the Titmus Stereo and Randot test.

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