Intraocular pressure according to different types of tonometry (non-contact and Goldmann applanation) in patients with different degrees of bilateral tearing

Purpose To investigate intraocular pressure (IOP) readings by non-contact tonometry (NCT) and Goldmann applanation tonometry (GAT) for patients with different degrees of bilateral tearing. Methods In this study, we reviewed the medical charts of patients complaining of different degrees of bilateral tearing. The tear meniscus height (TMH) and lOP with NCT and GAT were measured. In each patient, a comparison of IOP readings between the eye with lower TMH and the contralateral eye with higher TMH was evaluated. The TMH was graded as follows: grade 1 (low): TMH < 0.2 mm; grade 2 (moderate): 0.2 mm <= TMH < 0.6 mm; grade 3 (high): TMH >= 0.6 mm. Subsequently, a comparison of 10P readings among eyes with low, moderate, and high TMH was also performed. Results A total of 120 eyes of 60 patients were enrolled. When comparing the two eyes of a patient, the eye with higher TMH showed higher NCT readings and larger difference in IOP readings between the two tonometries than the eye with lower TMH (P < 0.001 and P < 0.001, respectively). When TMH was classified into grades according to the degree, the high TMH eyes showed higher NCT readings than did the low and moderate TMH eyes (P < 0.001 and P = 0.001, respectively). In addition, the high TMH eyes showed a larger difference in IOP readings between the two tonometries than did the low and moderate TMH eyes (P < 0.001 and P < 0.001, respectively). Conclusion Eyes with higher TMH showed higher NCT readings and a larger difference in IOP between the two tonometries (NCT and GAT) than those with lower TMH. In patients with tearing, the NCT value may be inaccurate, so it is necessary to measure the GAT.