ABO Practice Test 2026 – Complete Exam Prep

Within opticianry, the concentric circle configuration found within the scope of the lensometer is known as the reticle. This is a specialized tool used to measure the prescription and power of a lens. The other options are all incorrect because they do not accurately describe the concentric circle configuration or its purpose within the lensometer. The front side is a term used to refer to the side of the lens closest to the wearer's eye, while base curve is a measurement used to determine the curvature of a lens. Pupil distance is a measurement used to fit eyeglasses to an individual's face, and is not specific to the lensometer or its configuration. Hence, option B, reticle, is the most accurate and specific choice for the concentric circle configuration within a lensometer.