Which sign is described as iris dance (iridodensis) in lens subluxation?

• A. Iris dance (iridodensis)
• B. Visible lens equator
• C. Phacodenesis
• D. Vitreal prolapse

Answer: (A)

Iris dance, or iridodonesis, is the tremulous appearance of the iris seen when the lens has subluxated due to weak or broken zonules. When the lens isn’t firmly supported, it moves with eye movements, causing the iris to ripple or “dance” in the pupil. This iris flutter is a telltale sign of insufficient lens support and is best appreciated with a slit-lamp exam, often becoming more evident as the pupil is examined under bright illumination.

Phacodenesis refers to tremulousness of the lens itself, not the iris, and while both indicate zonular weakness, they describe different tissues. Visible lens equator indicates that the edge of the lens is displaced and can be seen, but it isn’t the iris’s movement. Vitreal prolapse is about vitreous pushing into the anterior chamber, a separate complication.