 Pollen exposure can result from direct hand transfer of pollen to the conjunctiva or, conceivably, from the forceful blowing of air, containing nasal secretions with antigen, up the nasolacrimal duct. The latter mechanism would be considered extremely unlikely because of the location of the nasolacrimal duct under the inferior turbinate the ducts location is in an area with little pollen exposure and the considerable force of air needed to cause reverse flow in the duct. The latter would also be true for topically applied intranasal drugs reaching the conjunctiva via the nasolacrimal duct, whereas the administration of medications to the conjunctiva frequently results in these medications reaching the nose via the nasolacrimal duct. 