Accuracy of the Lacrimal Syringing Test in Relation to Dacryocystography and Dacryoendoscopy

This study aimed to evaluate the accuracy of the lacrimal syringing test (syringing) in relation to dacryocystography (DCG) and dacryoendoscopy (DE) in lacrimal pathway (LP) obstruction.

We retrospectively reviewed 101 patients (188 LPs) who underwent syringing, cone-beam computed tomography (CBCT)-DCG, and DE to diagnose the degree and site of LP obstruction. The degree of obstruction was classified into patent, partial obstruction, and complete obstruction. The degree of LP obstruction was determined by combining the findings of DE and CBCT-DCG and was designated as DCG+DE. When differentiating complete or partial obstruction on DE was uncertain, complete or partial obstruction was assigned if the DCG showed evidence of contrast media obstruction or passage, respectively. The consistency between syringing and DCG+DE was evaluated by calculating the weighted kappa coefficient.

The sensitivity and specificity of syringing were 94% and 89%, respectively. The weighted Cohen's kappa value of agreement between syringing and DCG+DE was κ = 0.73 (SE = 0.04, 95% confidence interval [CI]: 0.66-0.80, p < 0.01). When divided into presaccal and postsaccal obstruction categories, the kappa values were κ = 0.40 (SE = 0.11, 95% CI: 0.19-0.62, p < 0.01) and 0.55 (SE = 0.09, 95% CI: 0.37-0.73, p < 0.01), respectively. Furthermore, when limited to common canaliculus obstruction (stenoses), which accounted for 78% (46 LPs) of the total presaccal obstructions, the kappa value was κ = 0.29 (SE = 0.12, 95% CI: 0.05-0.54, p = 0.021), which demonstrated the lowest consistency between syringing and DCG+DE.

Syringing was "substantially" in agreement with DCG+DE in detecting the degree of LP obstruction. Moreover, syringing was a sufficiently sensitive and specific test when performed by an experienced clinician. However, distinguishing between complete and partial obstructions by syringing was sometimes difficult, particularly in the common canaliculus obstruction (stenosis).