What is phacodonesis?

What is phacodonesis?

• A. Trembling of the iris
• B. Trembling of the pupil
• C. Trembling of the ciliary body
• D. Trembling of the lens

Answer: (D)

Phacodonesis refers to trembling or wavering of the crystalline lens because its zonular suspensory fibers are weak or damaged. Since the lens is normally held in place by these fibers, any loss of support lets the lens rock or oscillate with eye movements or during accommodation. This lens instability is what you’re seeing as tremor of the lens on examination. It’s distinct from tremor of other ocular structures. Iridodonesis is trembling of the iris, which can occur when zonules are lax but denotes the iris moving rather than the lens. Trembling of the pupil or ciliary body isn’t the term used for this phenomenon. So the correct description specifically points to the lens trembling, i.e., phacodonesis, and it signals compromised zonular support often seen with trauma, pseudoexfoliation, hypermature cataracts, or connective tissue disorders.

Phacodonesis refers to trembling or wavering of the crystalline lens because its zonular suspensory fibers are weak or damaged. Since the lens is normally held in place by these fibers, any loss of support lets the lens rock or oscillate with eye movements or during accommodation. This lens instability is what you’re seeing as tremor of the lens on examination.

It’s distinct from tremor of other ocular structures. Iridodonesis is trembling of the iris, which can occur when zonules are lax but denotes the iris moving rather than the lens. Trembling of the pupil or ciliary body isn’t the term used for this phenomenon. So the correct description specifically points to the lens trembling, i.e., phacodonesis, and it signals compromised zonular support often seen with trauma, pseudoexfoliation, hypermature cataracts, or connective tissue disorders.