Fig. 15. Sequential operative photographs of the epithelial fluorescence pattern seen during phototherapeutic keratectomy (PTK) for microstriae. A. Initial perforation over most elevated region of striae. B. With successive pulses, epithelial fluorescence over most elevated striae disappears. C. With further pulses, the epithelium between the striae recedes, with further reduction in fluorescence. D. At the end of the transepithelial phase of the PTK, most of the epithelium is removed, with only minimal residual fluorescence in the areas of thickest epithelium between the striae. (Reproduced with permission from Steinert RF, Ashrafzadeh A, Hersh PS: Results of phototherapeutic keratectomy in the management of flap striae after LASIK. Ophthalmology 111:740, 2004)