Patients place their head in a support and chin rest and a single drop of 0.01 ml is delivered to each eye.

[4] Various quantification models have been developed, which must account for the variable drainage of asymptomatic systems.

DSG is considered the best method to quantitatively assess the proportion of the dose drained in this way.

[6] It can also be useful in assessing functional problems, where the lacrimal system appears unobstructed, and for post-operative progress.

[7][8] Advantages of DSG over dacrocystography include better functional information and a lack of injection.