Aqueous column changes in the episcleral veins after the instillation of ripasudil versus latanoprost: a randomized, double-blind, crossover clinical trial.

To investigate whether the topical administration of ripasudil ophthalmic solution enhances aqueous outflow in the episcleral vein of the human eye. Two-sequence, prospective, randomized, double-blind, crossover trial. Sixteen eyes of 16 healthy participants were recruited in this study. Participants were randomized into one of the two crossover sequences to the instillation of ripasudil or the control drug, latanoprost, followed by a washout period of more than 2 days, and crossed over to the alternative instillation. The aqueous columns in the episcleral veins were recorded using a video capture system connected to a slit-light microscope (hemoglobin video imaging) before and 2 and 8 h after the instillation. Comparisons between ripasudil and latanoprost for the changes of the aqueous column width after the instillation. Two hours after the instillation, the ripasudil group had significantly greater dilation of the aqueous column width than the latanoprost group. Eight hours after the instillation, the ripasudil group had significantly greater dilation of the aqueous column width than the latanoprost group. Hemoglobin video imaging revealed that the topical administration of ripasudil ophthalmic solution enhanced aqueous outflow in the episcleral vein of the human eye.