Electrolytes and electrophoretic studies of tear proteins in tears of patients with nasolacrimal duct obstruction.

This study was performed to determine whether there are differences in tear constituents between normal persons and patients with primary acquired nasolacrimal duct obstruction (PANDO) and to correlate differences in tear composition with the degree of PANDO. We tested 30 normal persons (mean age 42.0 +/- 21.4 years) and 34 PANDO patients (mean age 44.8 +/- 17.9 years) consisting of 18 cases with complete obstruction and 16 cases with partial obstruction. We measured the pH, the concentration of Na(+), K(+), Cl(-), total calcium and total protein of the tears. The composition of tear protein was assessed by cellulose acetate electrophoresis. The data were analyzed by a t test. The pH was more alkaline in patients with PANDO (7.11 +/- 0.38), especially in cases with complete obstruction (7.14 +/- 0.30, p = 0.47) compared with the normal persons (6.94 +/- 0.35). The concentration of Na(+), K(+), Cl(-) and total protein were similar in normal and PANDO cases, while total calcium concentration was significantly higher in PANDO (2.62 +/- 1.70 mg/dl) compared with the normal cases (1.73 +/- 0.97 mg/dl), (p = 0.015). This change was found in both cases with complete obstruction (2.47 +/- 1.25 mg/dl, p = 0.027) and cases with partial obstruction (3.00 +/- 2.16 mg/dl, p = 0.009). PANDO patients had lower levels of tear protein fraction (TPF) 1 (p = 0.006) and higher levels of tear TPF 4 (p = 0.000) than normal persons. Tears in PANDO cases were more alkaline, higher in calcium concentration, and unstable in the proportion of tear proteins compared with normal persons. These results may improve our understanding of tear physiology and the pathogenesis of PANDO.