Worth 4-Dot test is used to:

• A. To measure accommodation amplitude.
• B. To assess suppression and diplopia across distance and near with red-green glasses.
• C. To assess color vision.
• D. To evaluate ocular alignment in still images.

Answer: (B)

The Worth 4-Dot test targets binocular function by checking whether one eye is being suppressed and whether there is double vision, and it does this at both distance and near using red-green glasses. When fusion is working, you should see all four dots. If one eye is suppressed, you’ll mainly see the dots from the open eye (red or green) at one or both distances. If diplopia is present, the patient may report or demonstrate seeing two sets of dots or an abnormal combination, indicating misalignment that creates double vision. This distance- and near-dependent check helps distinguish suppression and diplopia, which is exactly what this test is designed to reveal.

It’s not about measuring how well the eye can accommodate, not a test of color vision, and not a static assessment of ocular alignment from a single image—the Worth 4-Dot specifically probes how the two eyes function together with red-green separation across distances.