American Board of Opticianry (ABO) Practice Test

Which measurement refers to the horizontal straight line between the farthest nasal and the farthest temporal point of a lens?

1. A-Box

2. Effective diameter

3. Saggital value

4. Binocular distance

The correct answer is: A-Box

The measurement that refers to the horizontal straight line between the farthest nasal and the farthest temporal point of a lens is called the A-Box. This measurement is important because it helps determine the overall fit and positioning of the lenses on the wearer's face. Option B, the Effective diameter, refers to the overall size of the lens and is not specific to the distance between the nasal and temporal points. Option C, the Saggital value, is a measurement used to determine the curvature of the lens and is not specific to the distance between the nasal and temporal points. Option D, the Binocular distance, refers to the distance between the pupils of the eyes and is not specific to the distance between the nasal and temporal points of the lens. This measurement is important for determining the placement of the optical center of the lens. Overall, the A-Box is the most accurate and precise measurement for determining the horizontal length of a lens.