[Is it possible to accurately measure intraocular pressure after refractive surgery?].

OBJECTIVE: To evaluate how the change of thickness or curving of the cornea after refraction operations (PRK or LASIK) influences the intraocular pressure (IOP) during assessment with a noncontact tonometer. PLACE OF INVESTIGATION: Ophthalmological Clinic SPAM and Ophthalmological ambulance EXCIMER. MATERIAL AND METHODS: With regard to the performed refraction operation the patients were divided into two groups. The first group comprised 87 patients where PRK was performed to correct myopia. The mean myopia in this group was -5.27 D +/- 2.32. The second group comprised 62 patients where LASIK surgery was performed to correct myopia. The mean myopia in this group was -10.18 +/- 4.36. IOP was assessed by means of a noncontact tonometer before and 6 months after surgery. RESULTS: In the first group a mean reduction of IOP by 4.8 +/- 2.1 mm Hg occurred. The central thickness of the cornea declined on average by 55.69 +/- 28.9 micros and the curving of the cornea diminished on average by 3.72 D +/- 1.76 D. In the second group of patients the IOP declined on average by 7.97 +/- 2.04 mm Hg. The central thickness of the cornea diminished by 78.75 microns +/- 42.26 and the curving of the cornea by 4.65 D +/- 2.07. In both groups a significant correlation was found between the reduction of IOP and the central thickness and curving of the cornea. CONCLUSION: Diminution of the thickness of the central cornea and diminution of the curving lead to lower values of the IOP. There is a direct correlation between thinning of the cornea and the decline of IOP.