Axis on eye report indicates what?

• A. Orientation of astigmatism
• B. Degree of refractive error
• C. Eye dominance
• D. Axis orientation

Answer: (D)

Axis on an eye report shows the orientation of the astigmatism correction, expressed as a degree angle. When the eye has astigmatism, the cornea or lens has different powers in different meridians, so glasses or contacts use a cylinder value to balance that difference. The axis tells you the direction of the cylinder’s orientation—in other words, the meridian along which there is no cylinder power, with the corrective power applied perpendicular to that axis. This is about where the astigmatism runs, not how strong the overall refractive error is. The magnitude of refractive error is shown by the sphere and cylinder numbers, and eye dominance isn’t indicated by the axis.