Feasibility of Strip Meniscometry for Tear Volume Evaluation in Lacrimal Passage Obstruction

Strip meniscometry tube (SMTube) is useful for assessing tear volume in dry eye disease. We performed an in vitro and a clinical study to examine whether the SMTube can also be used to evaluate tear quantity in lacrimal passage obstruction (LPO). In vitro experiments showed that the SMTube value and the amount of water absorption were significantly correlated (R(2) = 0.816, p = 0.0008), but the measured value peaked when 4 μL was absorbed. In the clinical study, 12 eyes of 9 LPO patients and 17 eyes of 17 healthy control subjects were included. The patients’ SMTube values were significantly higher than those of the control subjects (p < 0.05). The SMTube value significantly decreased after silicon tube intubation (p < 0.05). Tear meniscus height (TMH) and area (TMA), measured by anterior segment optical coherence tomography, exhibited a significant positive correlation with the SMTube value (TMH, p < 0.001, R(2) = 0.396; TMA, p < 0.001, R(2) = 0.366). Moreover, the SMTube value significantly correlated positively with the subjective symptom of epiphora (p = 0.012, R(2) = 0.255). Thus, SMTube was useful for evaluating the tear volume and therapeutic effects in patients with LPO.