To investigate the effects of pupil dilation and constriction agents on the survival and production of nitric oxide (NO) in cultured human trabecular meshwork cells (HTMC).

Primarily cultured HTMC were exposed to 0, 0.01, and 0.1 mg/ml of tropicamide, cyclopentolate, atropine, or pilocarpine for 2 hours. Cellular survival and production of NO were assessed using the MTT assay and Griess assay, respectively.

Tropicamide, cyclopentolate, atropine, and pilocarpine decreased cellular survival at the concentration of 0.1 mg. At the concentration of 0.01 mg/ml, all agents decreased production of NO to some extent, although the reduction was not statistically significant.

Pupil dilation and constriction agents may be toxic to HTMC if used at high concentrations or if used frequently in the short-term but may not affect trabecular outflow.