ABSTRACT
The authors' clinical experience has suggested that the noncontact tonometer (NCT) has a tendency to record a lower intraocular pressure(IOP) than the Goldmann applanation tonometer(GAT) after excimer laser photo refractive keratectomy(PRK). This study was done to verify this tendency. We performed PRK on 177 eyes of 122 patients using a VISX 20/20 excimer laser, and topical fluorometholone was used after PRK. The eyes were divided into three groups according to their ablation depths, and the IOP was measured with the GAT and the Topcon NCT before surgery and 1, 3, 6, 9, and 12 months postoperatively. The mean postoperative IOP measured with the GAT or the NCT decreased as compared with the mean preoperative IOP(GAT: 1.67 ~ 2.90 mmHg, NCT:5.27 ~ 6.54 mmHg). The mean NCT reading was 1.12 mmHg higher than the mean GAT reading preoperatively, but was 2.48 ~ 2.88 mmHg lower than the mean GAT reading postoperatively. Difference between GAT and NCT measurements postoperatively was more prominent in the group of deeper ablation. These results suggest that we should be cautious of evaluating the IOP measured with the GAT or the NCT after PRK.