This study was designed to investigate the effect of a single-drop instillation of different lacrimal substitutes on tear film thickness (TFT) assessed with optical coherence tomography in patients with mild to moderate dry eye disease.
The study was performed in a randomized, double-masked, controlled parallel group design. Patients received a single dose of either unpreserved trehalose 30 mg/mL and sodium hyaluronate 1.5 mg/mL (TH-SH, Thealoz Duo), unpreserved sodium hyaluronate, 0.15% (HA, Hyabak) or sodium chloride, 0.9% (NaCl, Hydrabak) eye drops. Sixty patients finished the study according to the protocol. TFT was measured with a custom-built ultrahigh-resolution Fourier domain optical coherence tomography system providing a resolution of 1.2 μm.
The mean TFT before treatment was 2.5 ± 0.4 μm. Ten minutes after instillation, TFT significantly increased in the TH-SH group from 2.4 ± 0.4 to 3.1 ± 0.9 μm (P < 0.01) and in the HA group from 2.4 ± 0.3 to 2.9 ± 0.5 μm (P < 0.01), whereas no significant change was observed in the NaCl group (from 2.6 ± 0.4 to 2.7 ± 0.4 μm, P = 0.76). The increase in TFT remained statistically significant up to 240 minutes after administration of TH-SH. In contrast, the increase in TFT after administration of HA was only statistically significant at 10, 20, and 40 minutes after drop instillation.
The findings of this study indicate that single instillation of TH-SH and HA eye drops increases TFT in patients with dry eye disease. The data also indicate longer corneal residence of the TH-containing eye drops. The effect of multiple instillation and long-term use of artificial tears on TFT warrants further investigation.
*Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria;
†Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria;
‡Department of Ophthalmology, Paracelsus University Salzburg, Salzburg, Austria; and
§Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
Reprints: Gerhard Garhofer, MD, Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria (e-mail: email@example.com).
Supported by an unrestricted grant from Laboratoires Thea, Clermont Ferrand, France.
The authors have no conflicts of interest to disclose.
Received October 15, 2014
Received in revised form November 13, 2014
Accepted November 22, 2014