The LCLS accelerator is presently in a commissioning phase and produces a 14GeV beam with normalized emittances on the order of one mm-mr, and peak current exceeding 3000 Amps. The design of the beam measurement system relies heavily on optical transition radiation profile monitors, in conjunction with transverse RF cavities, and conventional energy spectrometers. It has been found that the high peak currents and small longitudinal phase space of the beam generate strong coherent optical emission that limits the quantitative use of OTR and other prompt optical diagnostics, requiring the use of wire scanners or fluorescent screen based measurements. We present the results of beam measurements, measurements of the coherent optical effects, and future plans for the diagnostics. Show Partial Abstract