Effect of hyaluronic acid on tear film thickness as assessed with ultra-high resolution optical coherence tomography

Abstract

Purpose: The aim of the present study was to assess the effect of a single drop of hyaluronic acid on tear film thickness (TFT) in healthy subjects.

Methods: 16 healthy subjects (8 male/ 8 female) aged between 20 and 36 years were included in this randomized, double-masked, placebo-controlled study. One eye received a single dose of hyaluronic acid eye drops (Olixia pure^®, Croma Pharma, Korneuburg, Austria), the fellow eye received physiologic saline solution as placebo control. The study eye was chosen randomly. TFT as measured with a custom built Fourier-domain optical coherence tomography (FD-OCT) system was the main outcome variable and measured before and every 10 minutes until 1 hour after topical administration.

Results: Baseline TFT was 4.8 ± 0.5 µm in the study eye and 5.0 ± 0.4 µm in the control eyes. Hyaluronic acid significantly increased TFT (p = 0.008 versus placebo) with a maximum effect 10 minutes after instillation (13.9 ± 11.9%). Post-hoc analysis revealed that an increase in TFT was seen until 30 minutes after administration compared to placebo. Data in the placebo group show high reproducibility with an intraclass correlation coefficient of 0.93 and a coefficient of variation of 5.4 ± 3.3%.

Conclusions: The data of the present study indicate that hyaluronic acid increases TFT for as long as 30 minutes in healthy subjects. In addition, our data provide evidence that our custom-built OCT system is capable of measuring residence time of lubricants on the ocular surface.