We modified a slit lamp (model SL-10L; Topcon, Tokyo, Japan) to incorporate two kinds of lasers. The beam of the argon laser at 488 nm (blue) and 514 nm (green) (Novus 2000; Coherent, Palo Alto, CA) was conducted through a reflection mirror and used as the slit light source to excite and visualize the fluorescent dye. To warm the target tissue, the beam of a diode laser at 810 nm (F-System; Coherent) was fed into a fiberoptic cable and applied to the fundus through the slit lamp. A zoom system of the diode laser allowed a continuously variable spot diameter (50–1000 μm). In addition, the duration and power of irradiation of the diode laser could be adjusted with an attached controller. A continuous diode laser application mode was installed and controlled by a foot switch. The diode laser spot was moved with a joystick. The images taken by the charge-coupled device (CCD) camera (Sony, Tokyo, Japan) mounted on the modified slit lamp are displayed on a monitor after being amplified by a video enhancer (Seprotec, Tokyo, Japan). These images can be recorded in media with S-VHS video recorder (Sony) for analysis. The sequences of video images are digitized by media converter (Sony) and analyzed with Adobe Photoshop (Mountain View, CA).