American Board of Opticianry (ABO) Practice Test

The sagittal value is considered an indicator of lens thickness in opticianry because it measures the distance between the thickest and thinnest points of the lens. This measurement is important in determining the overall thickness of the lens and ensuring proper fit for the wearer. Base curves do not directly indicate lens thickness, but rather the curvature of the lens. Prism tint is a type of lens coating and does not accurately measure thickness. Effective diameter is simply the size of the lens and does not reflect its thickness.