Worth Test: Optometry Practical Sheet
- maudoptical
- Apr 8
- 2 min read
Updated: Apr 9
Objective of Worth Test
To identify the first two degrees of binocular vision: simultaneous vision (1st degree) and fusion (2nd degree), as well as a possible fixation disparity.
Principle
The Worth test is based on a partial and sensory dissociation of binocular vision using red and green filters.
Red and green symbols are used to evaluate simultaneous vision (1st degree).
The white symbol, visible to both eyes, is not dissociated and allows verification of fusion (2nd degree).
The patient is asked to indicate:
how many symbols they perceive in total,
whether the upper red dot is centered relative to the two green dots,
and, if not centered, whether it is shifted to the right or to the left.
These responses make it possible to assess the quality of binocular vision and to detect fixation disparity.
Test Conditions
Performed using a phoropter or trial frame
Test performed in binocular vision.
Use of the patient’s theoretical or habitual correction.
Correct positioning of red and green filters.
Appropriate test distance: distance vision or near vision
Common Student Mistakes ❌
Reversing the interpretation of red and green colors.
Forgetting to place the filters before starting the test.
Inability to draw conclusions from the patient’s responses (simultaneous vision, fusion, fixation disparity).
Conclusion
The Worth test is an essential test for quickly assessing binocular vision. It allows you to evaluate simultaneous vision, fusion, and detect a possible fixation disparity.
Simple to perform, it is clearly one of the tests to master during a comprehensive eye examination.
This test is commonly used in clinical practice, but also in exams, especially for optometry students, orthoptic students, and optician students.
It is therefore very important to master this test to succeed in clinical exams, but also to feel confident when working with real patients afterwards.
