  Adequate therapeutic retinal laser irradiation needs to be adapted to the
local absorption. This leads to time-consuming treatments as the laser power
needs to be successively adjusted to avoid under- and overtreatment caused by
too low or too high temperatures. Closed-loop control can overcome this burden
by means of temperature measurements. To allow for model predictive control
schemes, the current state and the spot-dependent absorption need to be
estimated. In this paper, we thoroughly compare moving horizon estimator (MHE)
and extended Kalman filter (EKF) designs for joint state and parameter
estimation. We consider two different scenarios, the estimation of one or two
unknown absorption coefficients. For one unknown parameter, both estimators
perform very similar. For two unknown parameters, we found that the MHE
benefits from active parameter constraints at the beginning of the estimation,
whereas after a settling time both estimators perform again very similar as
long as the parameters are inside the considered parameter bounds.
