Titmus fly test

Test Components

- Handheld stereoscopic slide viewer

- Slide containing the Titmus Fly image

- Single peripheral stimuli (Titmus Circles and Animals)

Titmus Fly Slide

- Central image of a fly with apparent depth

- Three-dimensional appearance due to binocular disparity

Peripheral Stimuli

- Titmus Circles: Concentric circles with depth cues

- Titmus Animals: Animal shapes with depth perception

Testing Procedure

Setup

1. Patient wears polarized glasses

2. Viewer positioned at a fixed distance (typically 40cm)

3. Adequate room illumination

Administration

1. Patient views the central fly image

2. Asks to describe the perceived depth of the fly

3. Moves on to peripheral circle and animal stimuli

4. Records observations and stereoacuity thresholds

Scoring and Interpretation

Titmus Fly Stereoacuity

- Normal response: Fly appears to "pop out" from the background

- Abnormal response: Fly appears flat or indistinct

Peripheral Stimulus Stereoacuity

- Titmus Circles: 3000, 800, 400, 200, 140, 100 seconds of arc

- Titmus Animals: 3000, 2000, 1000 seconds of arc

Interpretation

- Normal stereoacuity: Able to perceive depth cues in fly and peripheral stimuli

- Reduced stereoacuity: Difficulty or inability to perceive depth

- Strabismus or amblyopia: May affect performance on test

Clinical Applications

Primary Uses

1. Rapid screening for stereoscopic vision

2. Assessment of binocular function

3. Evaluation of vision therapy outcomes

4. Pre-/post-operative assessment

Advantages

- Quick and easy administration

- Portable and compact design

- Provides qualitative and quantitative data

- Useful for both children and adults

Limitations

- Limited range of stereoacuity measurement

- Susceptible to patient understanding and compliance

- Potential for false positives or negatives

- Not suitable for severe binocular disorders

Special Considerations

Viewing Conditions

- Proper polarized glasses usage

- Appropriate illumination levels

- Consistent testing distance

Patient Factors

- Refractive error correction

- Cognitive and language abilities

- Attention span and motivation

Test Limitations

- Cannot differentiate specific binocular defects

- May not detect mild stereopsis impairments

- Subjective nature of patient responses

Professional Applications

Orthoptic Assessments

- Routine vision screenings

- Binocular vision evaluations

- Vision therapy progress monitoring

- Pre-/post-surgical assessments

Occupational Screenings

- Aviation and aerospace industries

- Military and law enforcement personnel

- Industrial jobs requiring depth perception

Conclusion

The Titmus Fly Test remains a valuable tool in orthoptic practice, providing a quick and convenient method for evaluating an individual's stereoscopic vision. While it has limitations in the range of stereoacuity it can measure, its simplicity and portability make it a useful screening instrument for both clinical and occupational settings.

Note : This document serves educational purposes exclusively and does not constitute medical advice or treatment guidelines