Photon correlation spectroscopy applied to tear analysis

[Display omitted] •Photon Correlation Spectroscopy is applied to human tears.•The hydrodynamic diameter of tear components is measured.•Tear hydrodynamic diameters of contact lens wearers and non-wearers are different.•Electron Spin Resonance is applied to human tears providing information on Fe species. This study aims to deepen the knowledge on tear film properties by the development of a protocol for analyses of Photon Correlation Spectroscopy (PCS) on human tears and by the comparison between PCS results obtained on tears of contact lens wearers and non-wearers. Tears (5μL) were collected by a glass capillary. The analyses provide the hydrodynamic diameter of tear components by analyzing intensity fluctuations in time of scattered light. PCS appears a promising technique for studying tear features and for shedding light on specific eye conditions, such as on the clinical effects of CL wear. In fact, statistical difference (p