Steady-state intraocular pressure (IOP) results from the interplay of the inflow, outflow, facility, and pressure of aqueous humor dynamics. A change in any one of these parameters may greatly affect IOP, while a simultaneous change in a second parameter might negate the effect of the first leaving IOP undisturbed. Some IOP changes could be rapid as when moving from a seated to a supine position. Other IOP changes are gradual such as seen seasonally. There is general agreement on the nighttime reduction in aqueous humor production but not on changes that occur during aging. Aging is confounded by many factors affecting IOP including systemic and ocular health, ethnic background, and recreational activities. Evidence suggests that aqueous humor dynamics in children may change rapidly until sexual maturity is reached, but the scarcity of research on children has left a void in our understanding of the developing eye. Efficacy of IOP-lowering treatments can be altered by fluctuations in aqueous humor dynamics, especially at night. The molecular and cellular aspects underlying the changes in aqueous humor dynamics is a rapidly growing field. Effective mathematical modeling of ocular fluid dynamics will benefit from a clearer understanding of the changes in aqueous humor dynamics throughout life.