A patient with a full-threshold 3+ nuclear sclerotic cataract experiences a −2.00 D myopic shift. The LEAST likely cause is:
A. Central lens index changes
B. Anterior lens displacement
C. Posterior lens displacement
D. Cortical hydration changes
Explanation: Nuclear sclerosis increases lens density and curvature, causing a myopic shift. Posterior lens displacement would create a hyperopic shift, not myopic. The nuclear changes include index of refraction increases, thickening, and anterior displacement.