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

## TL;DR

This study evaluates how well the fluorescein efflux test can detect blockages in children's tear ducts, finding it more accurate for complete obstructions.

## Contribution

The study provides new diagnostic accuracy data for the fluorescein efflux test in congenital nasolacrimal duct obstruction in children.

## Key findings

- FET had 77% sensitivity and 33% specificity for CNLDO.
- FET showed 86% sensitivity and 83% specificity for complete LDO.
- FET is more accurate for complete obstructions than partial ones.

## Abstract

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.