is misleading as it implies occluded drainage and solely nasolacrimal duct pathology. 'Normal' tear dynamics cannot be defined, comprising of a complex interplay of tear production, evaporation ...

(a) The frontal processes of the maxilla and the lacrimal bone are removed to expose the nasolacrimal duct and the lacrimal sac. (b) The mucous nasolacrimal duct and the lacrimal sac are elevated ...

If the duct is blocked, the tissue is likely to be irritated and fragile. Using a metal cannula may damage the lacrimal sac and nasolacrimal duct; a safer alternative is a soft Teflon catheter (Fig.