Which of the following is NOT measured under disassociated conditions?

• A. Maddox Rod
• B. Wesson card
• C. Alternating cover test
• D. Von Graefe phorias

Answer: (B)

The main idea here is understanding which tests disrupt binocular fusion to reveal latent misalignment and which tests allow fusion to remain while measuring alignment.

Disassociated conditions deliberately break or reduce fusion so any latent deviation (a phoria) shows up clearly. Maddox rod creates a dissimilar image, prompting diplopia that lets you quantify the misalignment. The alternating cover test periodically hides one eye to prevent simultaneous viewing, again breaking fusion to measure a latent deviation. The Von Graefe phoria test uses prisms to split the images seen by each eye, removing fusion so the phoria can be measured.

The Wesson card, on the other hand, is used with both eyes open and fusion maintained; the target is viewed binocularly and deviations are assessed while the patient fuses the images. Because it relies on associated viewing rather than disassociation, it is not measured under disassociated conditions.