Certified Paraoptometric (CPO) Practice Exam

The term that refers to the cylinder's location within the lens is "Axis." In optometry, the axis is crucial as it indicates the orientation of the cylindrical power of a lens, typically measured in degrees. This placement determines how the lens corrects astigmatism, ensuring the light entering the eye is correctly focused on the retina. The axis is defined as the meridian of the lens that has no cylindrical power, which is vital for the precise fitting and functioning of lenses designed to correct irregularities in the eye's curvature. Understanding the axis allows optometrists and paraoptometric practitioners to provide accurate prescriptions and improve patients' visual acuity effectively.