Which lens design would provide the best visual results for a prescription of RX -3.00 sphere?

The lens design that would provide the best visual results for a prescription of RX -3.00 sphere is a soft spherical lens. This design works particularly well for patients with simple myopic prescriptions like this one because it offers a uniform refractive power across the lens surface. A soft spherical lens is designed to correct for spherical errors without adding complications that come with astigmatism correction.

In the case of a -3.00 sphere prescription, the spherical design is effective for achieving clear vision since the patient's refractive error is purely spherical. These lenses are also typically more comfortable and easier to adapt to, making them ideal for everyday use.

Other designs, such as soft toric lenses, are used specifically for astigmatism, which is not relevant in this scenario. Spherical gas permeable lenses with increased center thickness could potentially induce distortion or discomfort, particularly if not properly fit. Truncated gas permeable lenses are better suited for specific fitting and application scenarios that may not be necessary for a straightforward spherical prescription.

Thus, the soft spherical lens stands out as the optimal choice for ensuring clear and comfortable vision for someone with a -3.00 sphere prescription.