Name

Analyse in vivo du film lacrymal par microscopie confocale non contact

Tears are composed of 98% water as well as various substances: the electrolytes (sodium, potassium, chloride...), glucose, urea, proteins, suspended epithelial cells and non-pathogenic saprophytic germs. Our objective is to analyze directly the contents of the precorneal tear film in normal subjects by using a new non-contact in vivo confocal microscope (non-contact IVCM).

In this study, we investigated 60 eyes of 30 normal subjects or other ocular surface diseases. In vivo confocal microscopy imaging (Heidelberg Retina Tomograph II Rostock Cornea Module) was performed with non-contact objective (Nikon 50x / 0,45 CF Plan EPI SLWD) for the precornea lacrimal film. The images obtained were consisted of two-dimensional 300x300 micron optical sections oriented parallel to the surface of the eye. 

In normal subjects, we demonstrated firstly the regularity of the tear film with the hyperreflective and dark areas, as well as the oil droplets scattered and desquamation of corneal epithelium. Secondly, we could observe the presence of normal bacteria. According to their morphology, they are possibly the staphylococcus epidermidis, propionibacterium acnes, coagulase-negative staphylococci, corynebacterium or staphylococcus aureus.

The non-contact IVCM facilitates also the observation of the presence of bacteria, which could be interesting to analyze in the infectious conditions. We present a reproducible and noninvasive investigation of the lacrimal film, is likely to open up a new promising way to investigate various ocular surface diseases and eventually the efficacy of therapy in the future.

The non-contact IVCM investigates the regularity and stability of tear film, which may contribute to understand the pathogenesis of dry eye.