Procedings of the Graphics Interface’95 Conference, Québec City, 17-19 may 1995, pp 155-162 Abstract Retinal laser photocoagulation has been used for a decade, but no real improvement in results has been observed.The simulator described in this paper, by separating actual practice from apprenticeship, allows one both to learn how to manipulate the equipment and to train oneself to make a diagnosis and to operate. An actual slit-lamp is supplied with sensors measuring all the degrees of freedom of the system. The images are calculated by a PC and are displayed on a miniature screen located inside the binocular. The purpose of this article is to describe the graphical part of the simulator, i.e. the modeling of the lens and the eye, the visualization algorithm and a real-time depth of field simulation. The goal is to synthesize images as close as possible to the actual view. Key Words: Medical Graphics, Graphics in simulation, Interactive Techniques, Graphics in Education. Introduction Retinal laser photocoagulation is a widely spread surgical technique. It has become one of the most important part of the ophthalmic area. The therapeutic effects of photocoagulation are no more to be demonstrated in retinal detachment prevention, diabetic retinopathy, A.R.M.D. (Age Related Macular Degeneration), etc... However, despite the number of installed equipments, no real improvement of complications which should have been solved has been observed. These can, in worst cases, lead to a complete blindness. One has the right to wonder if the apprenticeship technique is not to be reviewed. A retinal laser photocoagulation simulator provides a good answer to the apprenticeship problem. The interest of such a simulator is the opportunity for the student to train as often as he wants and to deal with very rare pathologies that he would have had little chance to meet during his relatively short training course. Moreover, it allows ophthalmologists to improve their skill during their continuous education or to prepare critical operations. Finally, it gives the ability to separate actual practice from apprenticeship, and therefore to lower the risks for the patients. The simulator has been designed as close as possible to the actual operating conditions. The slit-lamp is kept, all the other tools and the patient are simulated. Sensors measure the positions of the different degrees of freedom and send the data to a PC computer which calculates the image to be displayed. Images are displayed in the binocular by means of a miniature screen. In order to synthesize realistic images, a texture mapping of an actual eye and an actual iris is used. Realism is increased by adding a lighting model of the slit-lamp and a blurring generation that simulates the focus. After a quick state of the art in medical simulators, we present a description of laser photocoagulation, the configuration of the simulator and the list of all the sensors. Next, the model of the eye, the visualization algorithms and a real-time depth of field simulation will be presented. 1 Previous work Medical simulators have been a recent research area. Compared to driving simulators, the use of medical simulators increases quite slowly. One of the reasons might be the reticence of the surgeons. Another reason is undoubtedly the complexity of the required algorithms within the medical area. Indeed, the surgeon not only visualizes the environment, but also interacts with it. That is why most simulators demand powerful Meseure P. 1 , Karpf S. 1 , Chaillou C. 1 , Dubois P. 2 , Rouland J.F. 3 1 Laboratoire d’Informatique Fondamentale de Lille Université des Sciences et Technologies de Lille 59655 Villeneuve d’Ascq Cedex, FRANCE Phone: (33) 20-43-65-57 Fax: (33) 20-43-65-66 E-mail: {meseure, karpf, chaillou}@lifl.fr 2 CLARC-Laboratoire de Biophysique, CH&U Lille, FRANCE 3 Clinique ophtalmologique, Hopital Huriez, CHU Lille FRANCE Low-Cost Medical Simulation: a Retinal Laser Photocoagulation Simulator