Purpose: In this study, we have researched the possible parametrically changes before and after LASIK (laser-assisted in situ keratomileusis) and the influence of these changes in the cause of post LASIK ectasia. Materials and methods: In this study 204 eyes with different refractive anomalies were included. Candidates that underwent refractive surgery first have to undergo many ophthalmological examinations, firstly by evaluating their visual acuity, subjective and objective refraction with and without cycloplegia, slight lamp evaluation, computerized topography, pupillometry, retina examination and measurement of intraocular pressure. Pachymetric values were measured with Orbscan IIz (Bausch Lomb). Refractive surgery was done with LASIK under local anesthesia. Results: In this study 102 patients were treated with LASIK who were with different refractive anomalies. According to the group age 44 or 43.1% were of the age 20 29, 46 or 45.1% were of the age 30 39, 11 or 10.8% were 40 49 years of age and 1 or 1% were above the age of 50 +. Pachymetric before surgery in right eye was approximately 565.4 μm (DS+- 39.4), from 507 μm up to 678 μm, but after surgery it was approximately 497.5 μm (DS+-61.7) from 346 μm up to 644 μm. Pachymetric on the left eye before surgery was approximately 564.8 μm (DS+-41.5) from 504 μm up to 696 μm but after surgery it was approximately 498.3 μm (DS+-62.2), from 329 μm up to 646 μm. Pachymetric in both eyes before surgery was approximately 549.1 μm (DS+=73.9), from 263 μm up to 687 μm. Pachymetric on both eyes after surgery was approximately 496.9 μm (DS+-60.1), from 337.5 μm up to 645 μm. With the Paired T test we have reached a significant statistical change between the pachymetric values in both eyes before and after the surgery (P
Key words: Pachymetric, Orbscan IIz, LASIK.