From that point on the whorl diameter increases rapidly, by which the shape of the shell becomes lenticular.

About 1.440 from the tip, the diameter increases to 0.338, creating a 0.15 driving band.

Doubling pupil diameter increases spherical aberration 16 times.

As the rolling occurs the wall thickness decreases as the diameter increases.

With aging the length increases by approximately 12% per decade, whereas the diameter increases by just 3% per decade.