The Intraocular Pressure Level before and after Laser in Situ Keratomileusis

Objective: To analyze the relationship between the decreased intraocular pressure (IOP) level after laser in situ keratomileusis (LASIK) and the preoperative central corneal thickness (CCT), postoperative CCT, and the central corneal ablation depth (CCAD). Materials and Methods: Prospective study of 52 patients (104 eyes) with myopia or myopic astigmatism. All subjects receiving LASIK surgery were analyzed with a mean follow-up time of 3 months. The examination included IOP 1 week before surgery and 3 months after surgery, the preoperative and postoperative CCT, the CCAD, anterior segment and fundus examination, and manifest and cycloplegic refraction. Results: There were 14 men and 38 women with a mean age of 28.6 years. The mean IOP levels were 14.5±2.8 mmHg 1 week preoperatively and 8.2±2.2 mmHg 3 months postoperatively. The mean decreased IOP level after LASIK was 6.3 mmHg. The mean preoperative CCT, postoperative CCT, and CCAD were 537.2±35.1, 435.3±33.8, and 101.89±21.27 μm respectively. The preoperative IOP positively correlated with the preoperative CCT; the postoperative IOP positively correlated with the postoperative CCT. Age showed no correlation with the preoperative or postoperative IOP. The difference in IOP level before and after LASIK was statistically significant and the decreased IOP level was significantly correlated with the preoperative IOP, but there were no correlations with patient age, CCAD, preoperative CCT and postoperative CCT. Conclusion: We suggest that the TOP reduction after LASIK must be kept in mind by ophthalmologists to avoid underestimating the IOP level.