What is lens subluxation?

What is lens subluxation?

• A. Complete displacement of the lens
• B. Absence of the lens in the anterior chamber
• C. Iridodonesis without lens movement
• D. Partial displacement of the lens

Answer: (D)

Lens subluxation means the lens has shifted from its normal position but is not completely displaced. This happens when the zonular fibers that hold the lens are weakened or partially torn, so the lens remains partially supported yet unstable. Because of this partial displacement, the lens may wobble with eye movements (phacodonesis) and the iris may appear to tremble (iridodonesis). You might also notice the edge of the lens or an irregular pupil and changes in vision or astigmatism. In contrast, complete dislocation (luxation) would mean the lens is fully displaced, potentially lying in the anterior chamber or the vitreous cavity. Absence of the lens in the anterior chamber describes anterior dislocation or aphakia, not subluxation. Iridodonesis without lens movement reflects iris tremor without the lens itself being displaced. Thus, the defining feature of subluxation is partial displacement of the lens.

Lens subluxation means the lens has shifted from its normal position but is not completely displaced. This happens when the zonular fibers that hold the lens are weakened or partially torn, so the lens remains partially supported yet unstable. Because of this partial displacement, the lens may wobble with eye movements (phacodonesis) and the iris may appear to tremble (iridodonesis). You might also notice the edge of the lens or an irregular pupil and changes in vision or astigmatism.

In contrast, complete dislocation (luxation) would mean the lens is fully displaced, potentially lying in the anterior chamber or the vitreous cavity. Absence of the lens in the anterior chamber describes anterior dislocation or aphakia, not subluxation. Iridodonesis without lens movement reflects iris tremor without the lens itself being displaced. Thus, the defining feature of subluxation is partial displacement of the lens.