Effects of 0.5% Tetracaine Hydrochloride on Central Corneal Thickness and Intraocular Pressure

1. Anita Manassakorn, MD
2. Winai Chaidaroon, MD

1. Chiang Mai University, Chiang Mai, Thailand

Purpose: To investigate the effect of 0.5% tetracaine hydrochloride on central corneal thickness (CCT) and intraocular pressure (IOP) in glaucoma patients.

Methods: This interventional case series included glaucoma subjects aged ≥ 18 years, with spherical refractive error less than ± 6 diopters (D) and astigmatism ≤ 3 D, with no ocular pathology, history of ocular surgery or contact lens wear. All underwent CCT and IOP measurement using Orbscan II and air-puff tonometer at baseline, and 1, 3, 5, 7, 9, 11, 13, and 15 minutes after application of 0.5% tetracaine. Friedman and Wilcoxon signed ranks test were used. An adjusted p value of < 0.006 was considered significant.

Results: There were 19 and 24 eyes eligible for CCT and IOP measurements. The mean ± SD ages were 62.7 ± 8.2 and 62.9 ± 8.3 years. The mean ± SD CCT at baseline was 527.8 ± 32.2 μm. The CCT did not change from baseline after instillation of 0.5% tetracaine eye drop (p = 0.071). The mean ± SD IOP at baseline was 13.2 ± 5.6 mmHg. The IOP significant decreased from baseline at 3, 7, and 11 minutes (p = 0.003, <0.001, and 0.002). Most of the eyes had IOP reduction less than 3 mmHg.

Conclusions: CCT and IOP change trends were different. Although IOP decreased from baseline, CCT did not show any change. This may support the influence of anesthetic eye drops on corneal biomechanical properties.