Abstract
Purpose: :
A deficiency of the lipid layer of the pre-corneal tear film is believed to be a major cause of evaporative dry eye. Comparing images of in vitro meibomian lipid films with in vivo images of the lipid layer using HRCM can aid modeling and testing and hence the understanding of lipid layer of the tear film.
Methods: :
Human meibomian lipids and cholesteryl esters were spread on an ionic buffer in a Langmuir Trough. Isocycles were performed at 20°C and 35°C. HRCM photographs were taken at different surface pressures.
Conclusions: :
Meibum spread on buffered saline is quite different from that of the pre-corneal tear film of comparable thickness, and both differ from the appearance of cholesteryl esters. This implies that the in vivo lipid layer contains additional components to those present in meibomian lipids. HRCM has advantages over other optical methods including "natural" color coding of thickness, low noise level, and high axial and lateral resolution. HRCM comparison of in vivo and in vitro images of meibum and its components promises to elucidate mechanisms involved in the structure of the tear film lipid layer.
Keywords: cornea: tears/tear film/dry eye • microscopy: light/fluorescence/immunohistochemistry • imaging/image analysis: non-clinical