Which sign indicates anterior lens luxation when visible on examination?

• A. VISIBLE lens equator
• B. Aphakic crescent
• C. Iris dance
• D. Phacodenesis

Answer: (A)

Anterior lens luxation causes the lens to move forward into the anterior chamber, so the clearest clue on exam is actually seeing the lens itself in front of the iris. If the lens has displaced anteriorly, its peripheral edge—the equator—can become visible as a curved margin in the anterior chamber. This direct visualization confirms that the lens is luxated rather than just decentered or unstable.

An aphakic crescent is seen when the lens is absent from the pupillary area, such as after lens removal or in aphakia, and does not indicate anterior luxation. Iris dance isn’t a standard sign of lens luxation, and phacodonesis reflects lens instability or tremor due to weakened zonules rather than a direct sign that the lens is luxated in front of the iris.