The Titmus test is a common eye chart used to assess stereopsis, which is the ability to perceive depth or three-dimensionality.
How the Titmus Test Works
The Titmus test consists of a series of cards with different images, typically circles or squares, arranged in various patterns. The images are designed to appear in different positions depending on the viewer's depth perception.
The test is administered by asking the patient to identify the images that appear closer or farther away. The test measures the smallest disparity in image position that the patient can detect, providing a measure of their stereopsis.
Types of Titmus Tests
There are several variations of the Titmus test, including:
- Titmus Fly Test: This is a common version used to assess stereopsis in children. It features a fly image that appears to be hovering above the card.
- Titmus Stereotest: This version features a variety of images, including circles, squares, and other shapes, arranged in different patterns.
- Titmus W-4 Test: This version is specifically designed to assess stereopsis in individuals with amblyopia (lazy eye).
Uses of the Titmus Test
The Titmus test is used in various settings, including:
- Eye exams: To assess stereopsis as part of a routine eye examination.
- Vision screening: To identify children with potential vision problems, including stereopsis deficits.
- Amblyopia treatment: To monitor the effectiveness of treatment for lazy eye.
- Occupational health: To assess the suitability of individuals for jobs requiring good depth perception.
Interpreting the Results
The results of the Titmus test are typically expressed in terms of the smallest disparity that the patient can detect. A smaller disparity indicates better stereopsis.
For example, a patient who can detect a disparity of 40 seconds of arc has better stereopsis than a patient who can only detect a disparity of 80 seconds of arc.
