When the nasolacrimal duct is blocked, tears cannot drain properly. This leads to several symptoms:
The most widely accepted method for nasolacrimal massage is the Crigler method. Success relies on proper technique; simply rubbing the skin is ineffective. The goal is to create hydrostatic pressure within the lacrimal sac to "pop" the membrane open.
To understand the mechanism of the massage, one must understand the anatomy of the lacrimal drainage system.