[In vitro toxicity of non-preserved artificial-tear formulations]

To analyse the putative toxic effect of three commercially available non-preserved artificial tear formulations on in vitro human conjunctival cells.

A conjunctival human epithelial cell line was exposed to Cellufresh, Oculotect and Acuolens formulations during 1, 3 and 24 hours. Cytotoxicity was measured by calculating the percentage of cell viability examination and scanning electron microscopy (SEM). Controls underwent exposure to supplement free DMEM-F12 (negative control) and exposure to 0.005% benzalkonium chloride solution (positive control).

Cell viability after 1 or 3 hours incubation with Cellufresh and Oculotect was similar to that obtained for negative controls. With Acuolens incubation however, cell viability showed significant reduction after 3 and 24 hours compared to control. SEM showed that Cellufresh and Oculotect exposed cells presented similar behavior to control cells. All three cell lines presented evidence of cellular surface alteration after incubation for 1 or 3 hours compared to controls, Acuolens showing the highest rate of alterations in exposed cells and an additional increment in cell loss was observed.

In the present study, non preserved artificial tears formulations showed a different degree in their in vitro toxicity, Acuolens being more toxic than Cellufresh or Oculotect.