What Is Nasolacrimal Probing?

How Does the "Metal Probe" Manually Open the Valve of Hasner?

The tear duct blockage in infants is usually caused by a "delayed opening" of the membrane at the bottom of the nose. During probing the surgeon uses a series of Bowman Probes, gradually increasing in size to navigate the 90-degree turn from the eyelid into the nasal cavity. The clinician knows the probe is in the correct spot when they feel a "Hard Bone Hit" against the side of the nose. The final "pop" through the membrane provides an immediate "data signal" that the drain is now open, allowing for a 100 percent clearance of stagnant tears.

What are the Primary Success Data Trends for Infant Probing?

Clinical data indicates that the success rate of nasolacrimal probing is highly dependent on the "Age of Intervention." Statistics show that probing has a 95 percent success rate when performed on children between the ages of 12 and 18 months. However if the procedure is delayed until age 3 the success rate drops to nearly 50 percent because the chronic inflammation causes the duct to "flesh in" with permanent scar tissue. This data has led pediatric ophthalmologists to recommend "Early Probing" for any child who has suffered more than three bouts of "dacryocystitis" (tear sac infection) before their first birthday.

Why Is "Probing and Irrigation" the Mandatory Double-Check?

After the probe is passed surgeons perform a "Flushing" or Irrigation test to prove the system is clear. A small amount of "Fluorescein" yellow dye is injected into the tear duct; if the dye is suctioned out of the child's throat it is objective proof that the surgery was successful. Data indicates that performing this "Irrigation check" reduces the rate of "Repeat Surgery" by nearly 20 percent. This ensures that any "secondary" blockages higher up in the system (the canaliculi) are identified and cleared during the same session.

What are the Specific Risks of "False Passages" in Adult Probing?

While standard for infants probing in adults is much more complex because adult blockages are often caused by "stones" or "calcium deposits." There is a risk that the probe could create a "False Passage" by tearing through the side of the delicate drainage tunnel. Data indicates that probing alone is only 20 percent successful in adults with "Complete" blockages. Identifying this "low success data" allows the surgeon to recommend a more definitive "DCR" surgery (creating a new hole) for adults, rather than putting them through a painful probing procedure that is unlikely to work.

How Do Clinicians Use "Silicone Intubation" for Recurrent Blockages?

If a child has a "failed" first probing the second procedure usually includes "Stenting" or Intubation. A tiny silicone tube, the diameter of a piece of hair is threaded through the tear duct and left in place for three months. The tube acts as a "scaffolding" to prevent the duct from healing shut again. Statistics show that silicone intubation increases the success rate to nearly 90 percent in "difficult" cases where simple probing failed. This "Safety Tube" is invisible to the child and does not interfere with blinking or normal tear production.