In ANSI standards, what degree measurement corresponds to cylinder axis for .75 to 1.50D?

The degree measurement that corresponds to the cylinder axis for a cylinder power of .75 to 1.50D is indeed 5 degrees, as specified by the ANSI (American National Standards Institute) standards. This measurement is important for ensuring the accurate alignment of cylindrical lenses in optical fittings.

ANSI standards dictate tolerances for the axis of cylindrical lenses to minimize visual distortion and ensure optimal visual acuity for the wearer. For prescriptions within the range of .75 to 1.50D, a tolerance of 5 degrees is established. This means that the actual cylinder axis can deviate by this amount from the prescribed axis, allowing for practical adjustments during lens fabrication and fitting.

Understanding this tolerance helps opticians provide frames and lenses that meet the required specifications for their patients, ensuring both comfort and clarity in vision. Thus, adherence to these standards is crucial for maintaining quality in optical practice.