Diagnostic Accuracy of the Fluorescein Efflux Test for Congenital Nasolacrimal Duct Obstruction.

OBJECTIVES

This study aimed to assess the diagnostic accuracy of the fluorescein efflux test (FET) for congenital nasolacrimal duct obstruction (CNLDO).

METHODS

We conducted a retrospective diagnostic accuracy study at a tertiary eye care center from September 2020 to December 2021. The study comprised 120 eyes from 97 patients aged <6 years suspected of CNLDO. After undergoing ophthalmologic examination, patients received both the fluorescein disappearance test (FDT) and FET. Dacryoendoscopy, syringing, and clinical findings served as reference standards. We differentiated between complete and partial lacrimal duct obstruction (LDO) by categorizing completely blocked cases as c-LDO. The primary outcome measured was the sensitivity and specificity of FET for CNLDO, with secondary outcomes focusing on sensitivity and specificity for c-LDO.

RESULTS

Of the 120 eyes, 102 eyes qualified for CNLDO diagnosis and 102 eyes for c-LDO diagnosis. FET demonstrated a sensitivity of 77% (95% CI: 68-85) and specificity of 33% (13-59) for CNLDO. Regarding c-LDO, FET showed a sensitivity of 86% (78-92) and a specificity of 83% (59-96).

CONCLUSIONS

The diagnostic accuracy of FET was lower in patients clinically diagnosed with CNLDO compared to those with c-LDO, as some patients did not exhibit true obstruction of the distal nasolacrimal duct. FET demonstrates high diagnostic accuracy for c-LDO and may assist in diagnosing lacrimal duct patency in children. It may also help exclude conditions other than lacrimal duct obstruction in pediatric patients presenting with epiphora and eye discharge.