How do tears drain? Technetium studies.

We examined the tear drainage system of twenty-fiv normal volunteers by scintillography with Technetium Tc 99m (Pertechnetate). We photographed the changes occurring in the lacrimal sac and nasolacrimal duct during closure and opening of the eyelids. Our findings support Jones' views of normal tear drainage. The tracer was concentrated in the lacrimal sac while the lids were closed for 3 minutes and descended into the nasolacrimal duct as soon as they opened.