The change in shape and internal form of the lens of the eye on accommodation.

Abstract A slit-image photographic technique is used to measure changes in the lens of the human eye on accommodation. It is found that the surfaces become conoid in the adult eye, which is more marked anteriorly than posteriorly, but in the child's eye the increase in curvature is spherical. The effect of the cornea in distorting the appearance is investigated and discounted. The anterior pole of the lens moves forward and the posterior pole moves back to a lesser extent. The lens centre moves forward. The equator of the lens and of the nucleus are reduced in diameter. The lens cortex is unchanged in thickness and the nucleus is markedly thickened. It is considered to be the nucleus which is active in changing the shape of the lens.