In recent years artificial tear drops addressing tear film osmolarity have come onto the market. Increased tear evaporation and reduced tear volume results in tear hyperosmolarity. This triggers an inflammatory process leading to apoptosis of goblet and epithelial cells. Trehalose, a naturally occurring disaccharide has been marketed. This study uses anterior segment ultra-high resolution optical coherence tomography (OCT) to assess pre corneal tear film thickness (TFT) following use of artificial tear drops; (i) Thelaoz Duo – Trehalose 30mg/ml, sodium hyaluronate 1.5mg/ml, sodium chloride, trometamol, hydrochloric acid (ii) Hyabak, unpreserved sodium hyaluronate 0.15% and (ii) Hydrabak – unpreserved sodium chloride 0.9%, sodium dihydrogen phosphate dehydrate, disodium hydrogen phosphate dodecahydrate; in patients with dry eye disease. The study found significant differences between artificial tears in increasing TFT after administration. Product (i) containing Trehalose & sodium hyaluronate increased TFT to 240 minutes compared to product (ii) containing sodium hyaluronate which had a TFT of 40 mins. Hyaluronic acid has been reported to have longer TFT times in previous studies using different measurement techniques. The Trehalose containing product had a significantly longer TFT time thought to be related to Trehalose interaction with lipid membranes and requires further investigation. There was no reported difference in patient satisfaction between the three drops.