Are all 585 nm pulsed dye lasers equivalent? A prospective, comparative, photometric, and histologic study

Flashlamp-pumped pulsed dye lasers (585 nm) are used to treat port-wine stains and other cutaneous vascular lesions. Strikingly different tissue effects were seen after two apparently similar 585 nm pulsed dye lasers at equivalent fluences were used.

We compared the photometric and histologic effects of two apparently similar 585 nm flashlamp-pumped pulsed dye laser systems.

The burn pattern and beam profile analysis of two Candela SPTL-1 lasers and two Cynosure Photogenica V lasers were compared. Various fluences and spot sizes of the Cynosure laser were placed on normal skin and evaluated for histologic change.

Variation between the stated area of the spot and the actual measured area of the spot was found in all lasers studied. The area of the 5 mm spot of the two Candela lasers studied was 35% and 31% larger, respectively, than the stated area. The Cynosure lasers had areas that were 8% and 4% smaller than the stated area. Neither beam profile was uniform. The Candela laser maintained a gaussian-like distribution of energy, whereas the Cynosure laser beam profile resembled a top hat with a more even distribution of energy. Histologic studies confirmed the maintenance of vascular specificity without nonspecific thermal damage.

When changing from one 585 nm pulsed dye laser to another and using supposedly equivalent fluences, one cannot guarantee that clinical results will be equivalent. In an effort to achieve consistent treatments when moving between lasers manufactured by different companies, it would be prudent to place a single spot of energy onto burn paper and measure the diameter of the spot.