An optical plane wave propagating through atmospheric turbulence is affected by irradiance fluctuations known as scintillation. The scintillation index of an optical wave in strong turbulence can be analyzed by extended Rytov theory, which uses filter functions to eliminate the effect of cell turbulence sizes that do not contribute to scintillation, and it already has been calculated by Kolmogorov's power spectral density model. However several experiments showed that Kolmogorov theory is sometimes incomplete to describe atmospheric turbulence properly. In this paper, for a horizontal path, we use extended Rytov theory to carry out plane wave scintillation index analysis in non Kolmogorov strong turbulence. We do it using a non Kolmogorov power spectrum which uses a generalized exponent factor and a generalized amplitude factor. Although our final expressions for the scintillation have been obtained by extended Rytov theory, which is necessary to adopt in strong turbulence conditions, they reduce to the proper results also in weak turbulence.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.