Eyelid “droop” from nonphysiologic causes can usually be distinguished by the position of the brow. In a patient with true ptosis, the brow is usually elevated as the patient tries to widen the palpebral fissure. With orbicularis overactivity, the brow is lowered.
Patients who feign ptosis generally cannot simultaneously elevate the eye and maintain a drooping eyelid. Thus, with upward gaze, the ptosis will “resolve.” Often the patient will realize this and not cooperate. In such cases, the examiner can use his or her thumb to manually elevate the ptotic eyelid and the patient will then look upward. The examiner’s thumb is then slowly moved away. If the ptosis returns, the condition may well have an organic basis, but if it “resolves,” then it is nonorganic.
Nonorganic blepharospasm may be unilateral or bilateral and typically occurs in children or young adults. It may be triggered by an emotionally traumatic event and may cause nonorganic ptosis. Pressure over the supraorbital notch is often useful in raising the eyelids.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.