The micro-reflux test - A new test to evaluate nasolacrimal duct obstruction

Objective: The authors describe a new and simple procedure, the Micro-Reflu x Test (MRT), to screen for primary acquired nasolacrimal duct obstruction (PANDO). This study sought to determine the reliability of this new test in the diagnosis of complete nasolacrimal duct obstruction. Design: A nonrandomized, prospective, self-controlled, comparative case ser ies. Participants: Two hundred eyes of 100 patients with documented unilateral c omplete PANDO were examined. Intervention: The MRT was performed by a masked examiner on both eyes of ea ch patient. Two drops of 0.25% sodium fluorescein dye were instilled in the inferior cul-de-sac and the patient made to blink five times to activate t he lacrimal pump mechanism. Excess fluorescein dye was blotted away using t issue paper. The patient was positioned at the slit lamp, and observation o f the inferior punctum with the cobalt blue filter was done using 5x magnif ication, The tissue overlying the lacrimal sac was massaged in a counterclo ckwise direction with moderate pressure using the index finger. The test wa s considered positive if there was continued observed reflux of fluorescein -stained tears from the inferior punctum after the initial counterclockwise massage to empty the inferior canaliculus. The validity of the MRT was mea sured by sensitivity and specificity as well as positive- and negative-pred ictive values. Main Outcome Measure: The MRT was considered positive if there was continue d reflux of fluorescein-stained tears from the inferior punctum after the i nitial digital massage to empty the dye from the inferior canaliculus. Results: The MRT used for the evaluation of complete PANDO has a sensitivit y of 97% and a specificity of 95%. It has a positive-predictive value of 95 % and a negative-predictive value of 97%. Conclusion: The MRT is a reliable screening test for presence of complete n asolacrimal duct obstruction.