Aren there distortions if the mask has a stronger power than the myope requires (whether atural or emporary myope)?
A As you’ve found in your practice, eyeglasses give multiple “cues” of a too-strong negative prescription (barrel distortion, size / distance distortions). But our domes are concentric with the eye’s rotational center, so the aforementioned distortions are completely non-existent. If the contact lens power (or natural myopic power) is less than +4.5 diopter, the ONLY deviation from distortionless vision is the focus-shift. If the diver can comfortably accommodate this focus shift (excess negative diopter), they remain completely unaware, unless the diver methodically tests his or her own close-focus ability an unlikely event. (top) 4.
