The effects of intraocular irrigating solutions on electroretinography have been extensively studied in animal models, but effects on human electroretinography have not been reported. This study examined the effects of two commercially available irrigating solutions, S-MA2 (Opeguard MA) and DE-057 (BBS-Plus) on 30-Hz flicker electroretinography during closed vitrectomy in humans. Eight eyes of 8 patients were examined. All patients underwent a simple vitrectomy without treatment of proliferative membrane. For 30-Hz flicker electroretinography recording, a contact lens with a built-in light-emitting diode was sterilized and used as both a stimulus source and a recording electrode. Replacing S-MA2 with DE-057 decreased the electroretinography amplitude from 55.8 +/- 15.2 to 45.5 +/- 13.2 microV (mean +/- SEM). Changing the irrigation solution from DE-057 back to S-MA2 increased the amplitude from 45.5 +/- 13.2 to 59.9 +/- 17.3 microV. However, these changes were not statistically significant. Replacing S-MA2 with DE-057 significantly increased the peak time from 50.1 +/- 1.5 to 57.6 +/- 1.3 msec (p < 0.001). This change was reversible; after changing from DE-057 back to S-MA2, the peak time of flicker electroretinography significantly decreased from 57.6 +/- 1.3 to 49.0 +/- 2.1 msec (p < 0.01). Thus intraoperative 30-Hz electroretinography showed delayed peak time during irrigation with DE-057, as compared with S-MA2. The lower potassium concentration and higher glucose concentration of S-MA2, as compared with DE-057, may be the cause of such electroretinography changes.