Worth 4 Dot testing in a dark room tests for which type of suppression?

• A. Shallow suppression
• B. Deep suppression
• C. No suppression
• D. Complete suppression

Answer: (B)

The Worth 4 Dot test is used to assess how strongly one eye’s input is being blocked by the brain, i.e., the depth of suppression. Doing it in a dark room reduces ambient visual cues and fusional opportunities, which makes suppression more likely to be revealed. Under these conditions, if one eye is being suppressed, the patient is more likely to report seeing input from only the seeing eye, or a markedly reduced set of dots, indicating that the suppression is deep rather than shallow or nonexistent. If there were no suppression, or only very shallow suppression with some residual input from the suppressed eye, the responses would show fusion or near-fusion cues instead. Hence, a dark-room Worth 4 Dot test emphasizes deep suppression.