A voice control system for ophthalmologic laser treatment systems sets parameters for delivering laser energy based on voice commands and prevents potentially harmful parameters due to operator mistakes and misunderstood voice commands by providing incremental parameter adjustment and restricting the amount by which the parameters can be adjusted for each executed voice command. Valid voice commands include indications of which parameter to set, a value for the parameter, and whether to increase or decrease the value of the parameter. In one example, parameter values can only be increased or decreased by a certain percentage with respect to the current value. In another example, the parameters are adjusted by selecting the next highest or lowest value with respect to the current parameter value from a predetermined sequence of possible values for particular parameters. Voice control functionality can also be deactivated under certain conditions such as when it is determined that a parameter was not set.
