TEAE is defined as any untoward medical occurrence or undesirable event(s) that begins or worsens following administration of the study drug, whether or not considered related to the treatment by the Investigator. A TEAE is considered serious if, in the view of the Investigator or Sponsor, it results in any of the following outcomes: death, a life-threatening TEAE, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or incapacity, a congenital anomaly or birth defect, an important medical event that jeopardized the participant and required medical intervention, or sight-threatening (possibly resulting in persistent or significant loss of vision). A summary of other non-serious adverse events (AEs) and all serious AEs, regardless of causality is located in Reported AE section.

Ocular redness using the Ora Calibra Ocular Hyperemia Scale was scored by the Investigator using the following scale (allowing half unit increments): 0=None; 1.0=Mild-Slightly dilated blood vessels, color of vessels is typically pink, can be quadrantal; 2.0=Moderate-More apparent dilation of blood vessels, vessel color is more intense (redder), involves the majority of the vessel bed; 3.0=Severe-Numerous and obvious dilated blood vessels, in the absence of chemosis the color is deep red, may be less red or pink in presence of chemosis, is not quadrantic; 4.0=Extremely Severe-Large, numerous, dilated blood vessels characterized by unusually severe deep red color, regardless of grade of chemosis, which involves the entire vessel bed. A lower score is indicative of less redness.

Blood samples will be collected for the determination of brimonidine in plasma at the specified time points on Day 1.