Which condition is typically bilateral in nature?

• A. Benign Essential Blepharospasm
• B. Myokymia
• C. Basal cell carcinoma
• D. Meibomian gland dysfunction

Answer: (A)

Benign essential blepharospasm is classically bilateral because it is a bilateral eyelid motor disorder (a focal dystonia) that involves the eyelid closers on both sides with symmetrical, involuntary spasms. The underlying circuits that control blinking are paired and coordinated, so the abnormal activity tends to affect both eyes rather than staying in one eye. While symptoms may start in one eye, progression to both eyes is common, making bilateral involvement the hallmark feature.

In contrast, myokymia usually presents as a fine, localized twitch of the eyelid and is typically unilateral and transient; basal cell carcinoma is a localized lesion on one lid; meibomian gland dysfunction affects the lid margins and can involve both lids but is not characterized primarily by bilateral eye involvement.