Syringing is Superior to ROPLAS for Detecting Nasolacrimal Duct Obstructions
Nasolacrimal duct syringing is superior to ROPLAS (Regurgitation On Pressure over the Lacrimal Sac) for detecting nasolacrimal duct obstructions due to its higher diagnostic accuracy and ability to directly assess patency.
Diagnostic Methods for Nasolacrimal Duct Obstruction
Syringing Technique
- Involves irrigation of the nasolacrimal system with saline solution through the punctum
- Directly assesses patency by determining if fluid passes through the system
- Provides immediate feedback on the presence and location of obstruction
- Can differentiate between:
- Complete obstruction (fluid regurgitates through same punctum)
- Partial obstruction/stenosis (some fluid passes but with resistance)
- Common canalicular block (regurgitation through opposite punctum)
ROPLAS Technique
- Non-invasive test involving digital pressure over the lacrimal sac
- Relies on observation of regurgitation of fluid/material from puncta
- Limited in detecting partial obstructions or precise location of blockage
- Cannot differentiate between different types of obstructions
Evidence Supporting Syringing Superiority
Macrodacryocystography (MDCG) studies have validated the superior accuracy of syringing compared to other diagnostic methods. In a comparative study, surgical findings were predicted by MDCG in 95.5% of cases but by probing/syringing alone in only 54% 1. This indicates that while syringing is superior to ROPLAS, it is most effective when combined with imaging techniques for complete assessment.
The diagnostic accuracy of syringing is particularly important when determining treatment options. For example, in cases of nasolacrimal duct stenosis versus complete obstruction, accurate diagnosis affects treatment outcomes. Endo-DCR (dacryocystorhinostomy) has been shown to have different success rates depending on whether patients have stenosis (41.7% resolution) versus complete obstruction (69.0% resolution) 2.
Clinical Applications and Considerations
When to Use Syringing
- Pre-surgical evaluation before cataract surgery
- Evaluation of epiphora (excessive tearing)
- Assessment of suspected nasolacrimal duct obstruction
- Determining appropriate surgical intervention (probing vs. DCR)
Limitations and Precautions
- Invasive procedure with risk of iatrogenic injury to the lacrimal drainage system 3
- Requires proper technique to avoid false results
- May be uncomfortable for patients
- Should be performed by experienced practitioners
Diagnostic Algorithm
- Begin with clinical assessment of epiphora
- Perform ROPLAS as initial non-invasive screening
- If ROPLAS is positive or symptoms persist despite negative ROPLAS, proceed to syringing
- For discordant results or complex cases, consider additional imaging (MDCG or dacryoscintigraphy)
- Use surgical findings as the gold standard for confirmation
Conclusion of Evidence
The evidence clearly demonstrates that syringing provides more accurate and detailed information about nasolacrimal duct patency than ROPLAS alone. In clinical practice, syringing allows for direct assessment of the drainage system and can identify the specific location and nature of obstructions, which is crucial for treatment planning and surgical decision-making.
While ROPLAS serves as a useful initial screening tool due to its non-invasive nature, it lacks the diagnostic precision of syringing, particularly for partial obstructions or for determining the exact location of blockages within the nasolacrimal system.