Final answer:
To clinically differentiate between true Von Graefe's sign and pseudo Von Graefe's sign, we need to examine their characteristics such as the presence of ptosis in different gaze positions.
Step-by-step explanation:
In order to clinically differentiate between true Von Graefe's sign and pseudo Von Graefe's sign, we need to examine the characteristics of each.
True Von Graefe's sign is a sign of thyroid eye disease and is characterized by:
- Ptosis (drooping of the eyelid) that is present in straight-ahead gaze
- Ptosis that disappears when the patient looks down
- Ptosis that is not evident when the patient looks to the side (adducted gaze)
- Less prominent ptosis when the patient looks to the side (abduction)
Pseudo Von Graefe's sign, on the other hand, is a false Von Graefe's sign that can occur in individuals without thyroid eye disease and can be caused by other factors, such as eyelid muscle weakness. It may present similarly to true Von Graefe's sign, but without the associated thyroid eye disease.