Which statement correctly differentiates lens subluxation from lens luxation?

Which statement correctly differentiates lens subluxation from lens luxation?

• A. Subluxation means complete displacement; Luxation is partial displacement.
• B. Subluxation is partial displacement; Luxation is complete displacement.
• C. Subluxation involves iris atrophy; Luxation involves corneal edema.
• D. Subluxation occurs in cats; Luxation occurs in dogs.

Answer: (B)

The main idea is how far the lens has moved and how much zonular support remains. In subluxation, the lens is only partially displaced because some zonules still hold it in place, so you may see signs like irregular pupil edges or trembling of the lens (phacodonesis). In luxation, the lens is completely dislodged from its normal position and can lie freely in the anterior chamber or the vitreous, potentially causing serious issues such as acute glaucoma if it ends up in the front of the eye. This is why the statement that subluxation is partial displacement and luxation is complete displacement is the best description. The other options mix up the definitions or bring in non-defining features (iris atrophy, corneal edema) or species-specific generalizations that don’t distinguish the two conditions.

The main idea is how far the lens has moved and how much zonular support remains. In subluxation, the lens is only partially displaced because some zonules still hold it in place, so you may see signs like irregular pupil edges or trembling of the lens (phacodonesis). In luxation, the lens is completely dislodged from its normal position and can lie freely in the anterior chamber or the vitreous, potentially causing serious issues such as acute glaucoma if it ends up in the front of the eye. This is why the statement that subluxation is partial displacement and luxation is complete displacement is the best description. The other options mix up the definitions or bring in non-defining features (iris atrophy, corneal edema) or species-specific generalizations that don’t distinguish the two conditions.