Which auxiliary trial lens will extend the keratometer range to approximately 61.00D?

The option of using a +1.25 D auxiliary trial lens is appropriate for extending the keratometer range to approximately 61.00D. When added to the keratometer's existing measurement range, the positive lens value increases the total effective power measured by the keratometer.

For a keratometer that typically measures corneal curves, a +1.25 D auxiliary lens allows the practitioner to measure steeper corneas that exceed the standard range. In this case, the addition of a +1.25 D lens raises the effective measurement and makes it possible to accurately assess curvature in greater detail without needing to switch to a different measurement device.

Using this approach helps ensure that even patients with high corneal powers can have their measurements taken accurately, which is critical for proper lens fitting and ocular health assessments. Thus, the selection of the +1.25 D lens is effective for achieving the desired range extension in keratometry.