When performing LARS, what axis is altered?

When performing LARS, what axis is altered?

• A. Spectacle axis
• B. Manifest refraction axis
• C. Lens axis
• D. Prism axis

Answer: (B)

The axis being adjusted in LARS is the axis of the cylinder in the manifest refraction. LARS is a procedure used during astigmatic correction to fine-tune how the cylindrical power is oriented according to the patient's subjective refraction. By rotating or recalibrating the cylinder axis in the manifest refraction, you align the correction with the eye’s actual astigmatic meridians as the patient perceives them, while keeping the cylinder magnitude and overall spherical correction consistent. The spectacle axis and the lens axis pertain to the physical orientation of the cylindrical power in glasses or a toric lens, and the prism axis concerns prism correction; they are not the axes that LARS modifies.

The axis being adjusted in LARS is the axis of the cylinder in the manifest refraction. LARS is a procedure used during astigmatic correction to fine-tune how the cylindrical power is oriented according to the patient's subjective refraction. By rotating or recalibrating the cylinder axis in the manifest refraction, you align the correction with the eye’s actual astigmatic meridians as the patient perceives them, while keeping the cylinder magnitude and overall spherical correction consistent. The spectacle axis and the lens axis pertain to the physical orientation of the cylindrical power in glasses or a toric lens, and the prism axis concerns prism correction; they are not the axes that LARS modifies.