What is the limitation of increasing dose or power with a short wavelength?

Increasing the dose or power with a short wavelength has a significant limitation in that it will not penetrate deeply into tissues. Short wavelengths are associated with higher energy but lower tissue penetration capabilities. This means that while the laser may be effective at the surface level, its effectiveness diminishes as the depth of penetration increases. Consequently, tissues deeper within the body may not receive adequate laser energy, which can limit the treatment's efficacy for conditions requiring deeper intervention.

When considering the context of the other choices, increasing safety risks may be a concern with higher doses or power levels generally, but it is more related to the risks of burns or damage to the superficial layers rather than a direct effect of the short wavelength. Distortion could refer to optical distortions or aberrations that can occur in certain contexts, but it's not a primary limitation of using short wavelengths with dose regulation. Equipment malfunction is also a potential risk with improper settings, but this does not specifically relate to the depth of tissue penetration influenced by wavelength. Thus, the key limitation when working with short wavelengths is indeed their reduced ability to penetrate deeply into tissues.