Purpose In view of research demonstrating the ability of anthocyanosides in a multiple oral dose to improve night vision in normal individuals, we assessed their effect on three night vision tests: full-field absolute scotopic retinal threshold (SRT), dark adaptation rate (DAR) and mesopic contrast sensitivity (MCS). Methods In a double-masked, placebo-controlled, cross-over study, 18 young normal volunteers were randomly assigned to one of three different regimens of multiple oral administrations of 12 and 24 mg anthocyanosides, and a placebo, given twice daily for 4 days. A 2 week washout period was allowed between each 4 day treatment period. SRT, DAR and MCS was tested 1 day before and at days 1, 2, 3 and 4 during the treatment period. Results No significant effect was found on any of the three above-mentioned night vision tests. The study had a power of 0.95 to detect a 0.1 log unit improvement in SRT and 0.5 log unit improvement in MCS. Conclusions Multiple oral administrations of 12 and 24 mg anthocyanosides twice a day appear to lack significant effect on night vision tests.
