Which test should be used to determine if a soft lens is inverted?

The taco test is a useful method for determining whether a soft contact lens is inverted. This test works by placing the lens on a flat surface and gently pressing it down with a finger. When the lens is in its correct orientation, the edges of the lens will curl downward, creating a shape similar to a taco. If the lens is inverted, the edges will flared outward, not achieving that desirable taco shape.

In examining the other methods, while the wet cell test is often used for various assessments of contact lenses, it does not provide direct visual feedback on lens orientation as effectively as the taco test. The burrito test, although sometimes mentioned in the context of lens evaluation, is less standardized and not commonly used for determining inversion. The radiuscope is a tool that measures the curvature of the lens but does not address the orientation directly. Thus, the taco test stands out as the most effective method for checking if a soft lens is inverted, making it the correct choice in this context.