Pulsed ultraviolet lasers can be used to indue clean etching in organic and some inorganic materials . This effect is called photoablation or ablative photodecomposition . Although the precise cause remains unknown , this phenomen on is becoming of vital importance in physitio materials processing and medicine . To better understand the photoablation process a theoretical descriptio process has been developed . this description is based on a threatment of the radiation traort of intense ultraviolet light pulsed through absorbing organic material . The theory predicts deviations from absorption law as high intensities which are in fact observed . these descriptio are due to three main effects: 1: Saturation of the finit number of choromophores in the material 2:multiphoton obsorption 3:attenuation of laser light by ablation products. Using the analysi to model the ablatio process it is possible to describe observed ablation behavior for a variety synthetic and biological substate . In order to analysis ablation process , we have used a numerical method based on finit diffrence. A fortran program has been developed to evaluate photon flux and deposited heat in tissue . We have also used polyamide as test media to calculate flux and energy deposition of laser ablation. Finally for better understanding of the process the eyes structure has been considered . The corona is a clear domin shaped layer which is located in the center of external layer of the eye.