Validity of Tono-pachymetry for Measuring Corrected Intraocular Pressure in Non-surgical and Post-photorefractive Keratectomy Eyes.
- Author:
In Kyun HAHN
1
;
Jae Yong KIM
;
Myoung Joon KIM
;
Hungwon TCHAH
;
Chan Hee MOON
Author Information
- Publication Type:Original Article
- Keywords: Corneal pachymetry; Intraocular pressure; Photorefractive keratectomy
- MeSH: Compensation and Redress; Corneal Pachymetry; Healthy Volunteers; Humans; Intraocular Pressure*; Manometry; Photorefractive Keratectomy; Ultrasonics
- From:Korean Journal of Ophthalmology 2017;31(1):44-51
- CountryRepublic of Korea
- Language:English
- Abstract: PURPOSE: To assess the validity of central corneal thickness (CCT) and corrected intraocular pressure (IOP) values obtained by tono-pachymetry in non-surgical and post-photorefractive keratectomy (PRK) eyes. METHODS: For the study, 108 young healthy participants and 108 patients who had PRK were enrolled. Measurements were randomly performed by tono-pachymetry, ultrasonic (US) pachymetry, and Goldmann applanation tonometry (GAT). CCT measurement by tono-pachymetry was compared to that of US pachymetry. The corrected IOP value obtained by tono-pachymetry was compared to that obtained by US pachymetry and GAT. The corrected IOP from US pachymetry and GAT was calculated using the identical compensation formula built into the tono-pachymetry. Bland-Altman plot and paired t-test were conducted to evaluate the between-method agreements. RESULTS: The mean CCT measurement using tono-pachymetry was significantly greater by 7.3 µm in non-surgical eyes (p < 0.001) and 17.8 µm in post-PRK eyes (p < 0.001) compared with US pachymetry. Differences were significant in both Bland-Altman plotand paired t-test. The mean difference of corrected IOP values obtained by tono-pachymetry and calculated from measurements by US pachymetry and GAT was 0.33 ± 0.87 mmHg in non-surgical eyes and 0.57 ± 1.08 mmHg in post-PRK eyes. The differences in the Bland-Altman plot were not significant. CONCLUSIONS: The CCT measurement determined using tono-pachymetrywas significantly thicker than that of US pachymetry. The difference in CCT was greater in post-PRK eyes than in non-surgical eyes. However, the corrected IOP value obtained by tono-pachymetry showed reasonable agreement with that calculated from US pachymetry and GAT measurements.
