Lacrimal scintigraphy: "interpretation more art than science".

Lacrimal scintigraphy (LS) or dacryoscintigraphy can demonstrate abnormalities in 80%-95% of patients with symptoms of epiphora and a patent lacrimal system on syringing and up to 40% asymptomatic individuals. Precise localization of the site of delay may not always be possible due to lack of anatomic detail on LS. LS is considered useful in patients with epiphora with delayed tear clearance and patency to syringing and suspected to have either nasolacrimal duct (NLD) stenosis or lacrimal pump failure. It remains unclear, however, as to whether LS can reliably distinguish between the two. The literature reports considerable variation in the technique, normative data, analysis, and interpretation of LS. Qualitative or visual analysis is simpler to perform and to our knowledge used more frequently in comparison to quantitative analysis. There is little extra information to be gained from LS in cases with complete NLD obstruction or severe NLD stenosis on syringing.