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Microsecond-pulsed wave lasers with high-peak power densities may be a better choice to minimize soft thrombus formation during endovenous laser ablation treatments.

Fluorometric studies have been made with modified slit-lamp microscopes. These instruments offered considerable versatility in modifying experimental parameters, but were seldom optimized in terms of detector and illuminator apertures, filter band-pass characteristics, detection system, light-source stabilization, or optical resolution. Improper control of these parameters can result in artifacts which override useful information. A new fluorophotometer for ocular research has been designed that utilizes an optical system, which eliminates the need for a contact lens. An effort was made to optimize both the axial resolution and the minimum detectable signal. The characteristics of standard barrier filters and excitation filters were examined and compared with photomultiplier sensitivity curves. It was necessary to use double filters in order to reduce artifacts due to excitation light that was not rejected by the barrier filter. In order to optimize the signal-to-noise ratio, a photon counting detection system was used. A dark current equivalent to 3 X 10(-10) g/ml allows a useful detection range of 1 X 10(-10) g/ml.

Nonablative skin resurfacing is a dermatologic procedure utilizing pulsed laser irradiation and dynamic cooling to induce selectively a wound healing response in the papillary and upper reticular dermis. Using temperature measurements of human skin provided by pulsed photothermal radiometry immediately following laser irradiation (=1.32 rim), spatial distribution of thermal damage is predicted in response to various potential therapeutic laser-cryogen doses. Results of our analysis suggest that appropriate application of pulsed laser irradiation and cryogen spray cooling may be used to protect the epidermis and selectively confine thermal injury to the papillary and upper reticular dermis. Development of nonablative skin resurfacing will require understanding the relationship between the degree of dermal photocoagulation and the cutaneous wound healing response following laser irradiation.