To diagnosis your condition, your doctor talks with you about your symptoms, examines your eyes and does a few tests. He or she will also examine the inside of your nose to determine if any structural disorders of your nasal passages are causing an obstruction. If your doctor suspects a blocked tear duct, he or she may have you undergo other tests to find the location of the blockage.
Tests used to diagnose a blocked tear duct include:
- Tear drainage test. This test measures how quickly your tears are draining. One drop of a special dye is placed on the surface of each eye. You may have a blocked tear duct if after five minutes most of the dye is still on the surface of your eye.
- Irrigation and probing. Your doctor may flush a saline solution through your tear drainage system to check how well it's draining. Or he or she may insert a slender instrument (probe) through the tiny drainage holes at the corner of your lid (puncta) to check for blockages. In some cases this probing may even fix the problem.
- Eye imaging tests. For these procedures, a contrast dye is passed from the puncta in the corner of your lid through your tear drainage system. Then X-ray, computerized tomography (CT) or magnetic resonance imaging (MRI) images are taken to find the location and cause of the blockage.