Which of the following is a sign of lens subluxation?

• A. Corneal edema
• B. Vitreal hemorrhage
• C. Anisocoria
• D. Aphakic crescent

Answer: (D)

Lens subluxation happens when the zonules holding the lens pull or tear, so the lens is not in its normal centered position. On slit-lamp exam this displacement often makes part of the lens edge visible as a crescent-shaped gap between the iris and the lens—what clinicians call an aphakic crescent. This sign directly reflects the uneven lens position from partial dislocation and is a classic clue to subluxation. Other signs listed aren’t specific to subluxation: corneal edema points to corneal or endothelial problems, vitreous hemorrhage suggests intraocular bleeding, and anisocoria is a broad finding with many causes. You may also see phacodonesis or iridodonesis (tremor of the lens or iris) with subluxation, which supports the diagnosis.