Background and objectives: To evaluate the in vitro energy attenuation by transpupillary thermotherapy (TTT) using an 810-nm diode laser after the treatment of exudative age-related macular degeneration.
Study design/materials and methods: In this experiment, an 810-nm diode laser was coupled to a slit lamp to deliver laser energy to a laser-power sensor adjusted in the track of the laser light. The spotlight was 0.5 mm in diameter; duration of exposure, 3 seconds. Citrated Pasteur pipettes were filled with blood diluted in saline in several concentrations and placed in the path of the laser light. The absorption of the light measured by the power sensor was tested for various delivered irradiances between 50.92 and 509.29 W/cm2. The differences were analyzed statistically.
Results: There were significant differences in laser blockage comparing various conditions for all power levels (P<0.05). Increasing the proportion of blood resulted in more laser blockage with all irradiances (P<0.05).
Conclusions: Blood significantly blocks the transmission of the 810-nm diode TTT laser.
(c) 2006 Wiley-Liss, Inc.