PURPOSE: To measure prospectively the early changes in corneal hysteresis, topography, and pachymetry after the creation of a stromal fl ap cut without laser photoablation. METHODS: A 37-year-old man was referred for a bioptic procedure to correct for compound myopic astigmatism in the left eye. A 159-µm-thick 8ϫ8.5-mm superior hinged fl ap was created with a mechanical microkeratome in the left cornea. Changes in the corneal hysteresis, corneal resistance factor, Goldmann correlated intraocular pressure (IOP), corneal compensated IOP, anterior and posterior topography, and optical and ultrasound pachymetry were monitored prospectively before and at 1 hour, 1 day, 5 days, and 25 days after the fl ap creation. The right eye served as a control.

Although myopic LASIK induced significant corneal aberrations, the level of partial compensation of corneal aberrations by internal structures remained unchanged. These results suggest that the previously described emmetropization that is effective during development may also be effective with acquired variations in corneal shape.