Jones test is used to detect:

Ans: a (Nasolacrimal duct obstruction) Ref: Khorana, 4th ed,p. 368Jones dye test is done in case of suspected obstruction and is of no value in total obstruction.Jones primary test:To differentiate between watering due to partial obstruction of the lacrimal passages from that due to primary secretion of tears (epiphora).Dye injected into the conjunctival sac fails to reach the nose, i.e., unstained cotton bud indicates negative test; eitherdue to partial duct obstruction or due to failure of lacrimal pump mechanism. To differentiate this, Jones test- 2 is performed.Jones test-2 (secondary test):In this lacrimal syringing is done. Positive test suggests dye was present in the sac. but could not reach the nose due to partial obstruction. Negative test indicates lacrimal pump failure.