Final answer:
Contacts show the most similar variation between doctors.
Step-by-step explanation:
Based on the provided information, the data set that shows the most similar variation between doctors is contacts. Contacts cover a significant portion of the cornea, providing superior peripheral vision compared to glasses. They also correct corneal astigmatism and create a regular optical surface. Skilled optometrists can adjust the power of the contact to compensate for any differences in curvature or tear layer thickness.