Contrast dacryocystography

Dacryocystorenography allows obtaining the most valuable information about the level and degree of obstruction of the lacrimal ducts.

Technique for performing dacricystography

• the lower lacrimal puncta are dilated with a Nettleship dilator;
• plastic catheters are inserted into the lower canals on both sides (the upper lacrimal point can be used);
• a contrast agent (usually 1 ml of lipoidol) is injected simultaneously on both sides and an X-ray is taken in the anteroposterior projection;
• After 5 minutes, a photograph is taken at a vertical angle to assess the effect of gravity on tear drainage.

Interpretation of dacricystogram

Failure of contrast to enter the nose indicates an anatomical obstruction, the location of which is usually obvious. A normal dacryocystogram in the presence of lacrimation indicates partial blockage or failure of the tear suction mechanism. Dacryocystography is also informative in the diagnosis of diverticula, fistulas, and filling defects caused by stones or tumors.

Scintillation of the lacrimal ducts

This is a complex test that evaluates drainage function in a wider range of physiological conditions than dacryocystography. Although scintilography does not provide the detailed visualization of anatomical changes that dacryocystography does, it is more informative in assessing partial blockages, especially in the upper part of the lacrimal drainage system. The test is performed as follows:

• 10 µl of technecium-99 radionuclide is injected into the conjunctival sac using a micropipette. The lacrimal fluid is labeled with this radioactive gamma-emitting substance;
• The glow is visualized with a gamma camera focused on the inner corner of the eye slit, and a sequence of images is recorded over 20 minutes.

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