Difference between Goldmann Applanation and Topcon Noncontact Tonometer Measurements after Excimer Laser Photorefractive Keratectomy.

Choi, Young In; Min, Hong Kee; Chim, Dae Geun

Original Article

Journal of the Korean Ophthalmological Society 1995;36(11):2014-2021.
Published online November 1, 1995.

Difference between Goldmann Applanation and Topcon Noncontact Tonometer Measurements after Excimer Laser Photorefractive Keratectomy.

Young In Choi, Hong Kee Min, Dae Geun Chim

¹Department of Ophthalmology, Hanil General Hospital, Seoul, Korea.
²Ghim's Eye Clinic, Seoul, Korea.

엑시머레이저 근시교정술후 Goldmann 압평안압계와 Topcon 비접촉성 안압계로 측정한 안압의 차이

최영인(Young In Choi),민홍기(Hong Kee Min),김대근(Dae Geun Ghim)

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.

Key Words: Corneal thickness;Excimer laser PRK;Goldmann applanation tonometer;Intraocular pressure;Topcon noncontact tonometer