Which adverse effect is commonly associated with prostaglandin analogs besides conjunctival hyperemia?

• A. Iris pigmentation changes
• B. Dysgeusia
• C. Eyelash growth
• D. Headache

Answer: (C)

Prostaglandin analogs not only lower intraocular pressure by increasing outflow, but they also affect structures around the eye in ways that patients often notice. The most recognizable extra effect, besides conjunctival redness, is eyelash growth. These drugs stimulate the hair follicles on the eyelids, extending the growth phase and producing longer, thicker, and sometimes darker lashes. This effect is well known and is even marketed clinically (lash growth products use the same mechanism).

While iris color changes can occur with long-term use in some individuals, and less common symptoms like taste disturbances or headaches can appear, the eyelash changes are the hallmark additional effect tied to how prostaglandin receptors act on eyelid hair follicles.