A 60 year old man presented with watering from his left eye since 1 year. Syringing revealed a patent drainage system.Rest of the ocular examination was normal. A provisional diagnosis of lacrimal pump failure was made. Confirmations of the diagnosis would be by:

Ans. is 'a' ie., Dacryoscintigraphy Out of the given options only Canaliculus irrigation test (ie. Jone's dye test) and Dacryoscintigraphy can diagnose lacrimal pump failure. (Rest two can only diagnose obstructive cause)Out of these two Dacryoscintigraphy is more specific and further Jones' dye test is useless in cases of complete obstruction. Jones dye test is performed only when partial obstruction is suspectedLet's see the cause of excessive wateringThese are only 3 basic causes of excessive wateringOver production of tearsMechanical obstruction of tear drainage Lacrimal pump failure due to lower lid laxity or weakness of the orbicularis muscleLacrimal pumpEye lids and the orbicularis muscle create a physiological pump which pumps the tears into the two puncta and then finally drain it into the inferior meatus through nasolacrimal ductEye lids are opposed against the globe, this creates a capillary action for the tearsOrbicularis muscle's contraction and relaxation creates a negative pressure in the lacrimal sac which sucks in the tears.Dacryoscintigraphy (or radio nucleotide Dacryo cystography)In this test a radioactive tracer (technitium99 or sulphur colloid) is instilled in to the conjunctival sac and its passage through the lacrimal drainage system is visualized with a gamma camera.It can very effectively diagnose lacrimal pump failure.