A number of recent studies have demonstrated the efficacy of transscleral Nd:YAG and diode cyclophotocoagulation in the reduction of intraocular pressure. The choice of an appropriate wavelength for this treatment modality has been based on a tradeoff of maximal transmission through the superficial layers of conjunctiva and sclera, and maximal absorption in the ciliary body. A UV-Vis-NIR spectrophotometer was used to determine the optical properties of the conjunctiva, sclera, and the ciliary body. These optical properties were used in a Monte Carlo Model to examine the fluence and the resulting rate of heat generation in each layer for the wavelengths of Nd:YAG (1064 nm), semiconductor diode (850 nm), Ruby (693 nm), Krypton yellow (568 nm), and Argon (514 nm) lasers. The results provided a basis for a theoretical prediction of the extent of thermal damage in the ciliary body as a result of transsclerral cyclophotocoagulation. Key Words: transscleral cyclophotocoagulation, Monte Carlo Model, rate of heat generation, Nd:YAG laser, Argon laser, Krypton laser, Ruby laser, semiconductor diode laser.