Abstract
Abstract: :
Purpose: To compare the beam intensity profiles of 2 different TTT lasers. Methods: A SP–980M camera (max resolution 640 x 480, max viewable beam 4.7mm, element pitch 8.4 x 9.8, spectral response 190 to 1100nm) was connected to a LPA–300PC 8 bit digitizer Spiricon (Logan, UT) beam profile analyzer to compare the 2D and 3D beam profiles of the following 810nm TTT Lasers: (1) The Iridex, Oculight SLx, CA USA. (2) The Quantel, Iridis, France. Both lasers were used with a Haag Streit type slit lamp adapter. Laser spot diameters of 2 and 3 mm were tested with a range of power from 200mW to 1000mW for each laser. Results: Beam profiles were obtained for 2mm and 3mm laser spots with each laser, allowing a comparison of the intensity, the general shape and the homogeneity of the profiles. Global intensity of the profiles was more influenced by the distance between the slit lamp adapter and the camera for the Quantel laser than for the Iridex laser. With the two lasers, the shape of the beam profiles were rather "top hat" for 3mm spots and rather gaussian with the 2mm spots. For the 3mm spots, the homogeneity of the beam profile was generally pretty good with the Iridex laser and variable with the Quantel laser. Conclusions: Our data first suggest that an adequate focus of the laser beam can be of dramatic importance for limiting sub or over dosages with TTT, especially with the Quantel laser. Second, the use of a 3mm spot seems more reliable than a 2mm spot because of the shape of the beam profile, whatever the laser used. Finally, among the parameters guiding the choice of a TTT laser the homogeneity of the beam intensity profile seems of great importance.
Keywords: laser • imaging/image analysis: non–clinical • age–related macular degeneration