Mechanism of tear flow after dacryocystorhinostomy and Jones' tube surgery.

In the 42 patients (84 eyes) in this study, 32 eyes had dacryocystorhinostomy (DCR), 15 had Jones' tube insertions, and the remaining 37 were considered controls. All patients were studied using nuclear scanning with computer interfacing quantitative lacrimal scintillography to determine the effects of blinking, respiration, and gravity on their functioning. Tears flowed through DCR openings faster than through the systems of normal patients. Patients with Jones' tubes demonstrated slower flow than in normal patients. The effect of respiration on tear flow was minimal, but blinking and lid function were important. Patients with eyelid laxity may show decreased flow even if the DCR and Jones' tubes are functional.