To evaluate the effects of trypan blue (TB) on the survival of cultured human trabecular meshwork cells (HTMCs).

Primarily cultured HTMCs were exposed to 0.05, 0.10 or 0.50% TB for 1, 5 or 30 min. Cellular survival was assessed using the MTT assay and degree of apoptosis was analyzed with flow cytometry using annexin-V/propidium iodide double staining.

Long-term exposure or high concentration of TB decreased the survival of HTMCs ( p < 0.05). In flow cytometric analysis, exposure to 0.50% TB for 30 min increased the degree of apoptosis ( p < 0.05). Commercial TB decreased cell survival after exposure for 5 min and increased the degree of apoptosis after exposure for 30 min ( p < 0.05).

TB may cause cellular damage of cultured HTMCs and apoptosis could be the underlying mechanism. In TB-assisted cataract surgery, TB should be used for the shortest time possible and removed completely.