Systems and methods provide for stabilizing the amount of laser energy delivered to a target from a laser device. Generally, delivered laser energy is measured over multiple laser pulses or over time in the case of a constant wave laser. A decrease is then calculated in the delivered energy, the decrease being caused by accumulation of one or more substances, such as ozone, along the laser beam delivery path due to passage of the laser beam along the path. Using this calculated decrease, a laser device may be adjusted to compensate for the decrease in delivered energy due to the accumulated substance(s), thus stabilizing the amount of energy delivered to the target.
