Which tool can help differentiate between a back toric lens and a bitoric lens?

A radiuscope is an effective tool for differentiating between a back toric lens and a bitoric lens because it measures the curvature of the lens surface. In a back toric lens, the toricity is located on the back surface of the lens, while a bitoric lens has both the front and back surfaces with different curvatures, creating two distinct areas of toricity. The radiuscope allows the practitioner to evaluate the specific curvatures on the lens and identify the presence of toricity on the back surface, which is crucial in determining whether it is a back toric or bitoric design.

Other tools listed, such as a keratometer, primarily measure the curvature of the cornea rather than the lens itself, making them less suitable for distinguishing between these types of lenses. A profile analyzer may provide additional information about the lens, but it is not specifically designed for the kind of curvature measurement needed to differentiate these two types effectively. A lensometer is useful for determining the prescription of the lens and cannot ascertain the specific design features that differentiate a back toric from a bitoric lens.