Resistance of Fluid Flow within the Nasolacrimal Duct

ABSTRACT

The presence of complete obstruction within the human lacrimal drainage system can be easily found. The partial obstruction within the lacrimal drainage system can be diagnosed with Jones dye test and radiologic test. However, above tests can't determine the degree of partial obstruction as qualitative methods. Authors designed the instrument that measures the resistance to constant fluid flow within the nasolacrimal duct. Author measured the resistance to 5 ml/min flow rate with stainless steel canula (internal diameter, 0.395 mm) within the nasolacrimal duct in 194 people (388 eyes) without epiphora. The means of the resistance in all cases are 187.64+/-42.37 mmHg.seconds/ml. There are no statistical significances in both eyes and sex groups. But in age groups between teens and 20s, 30s and 40s, 60s and over 70s, there are statistically significant. Between the age and the resistance the coefficiency of correlation(r) is 0.56 in right eye, 0.64 in left eye, 0.60 in both eyes and as a result of regression, statistical significance showed (p-value<0.01). Authors suggested the normal value of the resistance in age and sex groups quantitatively. On the basis of this measurement, it is possible to make the early diagnosis and the proper plan of treatment in the partial obstruction of the nasolacrimal duct, the differential diagnosis between epiphora from the partial obstruction within the nasolacrimal duct and from other causes.