Diurnal variation of human tear meniscus volume measured with tear strip meniscometry self-examination

PurposeTear secretion is critical for maintenance of healthy ocular surface and vision. Most of normal subjects and dry eye patients feel worsening of ocular dryness in the afternoon, however, diurnal variation of tear meniscus volume has not been directly measured because there was no appropriate method. We used a simple, non-invasive technique, tear strip meniscometry (SM) by self-examination. Previous investigations indicated the values of SM correlated strongly with those of the Schirmer test, tests of tear break up time, and tear meniscus height measurement by anterior optical coherence tomography. The purpose of this study was to capture diurnal variation of aqueous availability at the tear meniscus by measuring wetted length using SM through self-examination.MethodsThirty-six medical personnel (mean age; 35.7 years) participated and SM self-examination was performed using a mirror seven times a day. The strip is applied for 5 seconds to the lateral side of the lower lid tear meniscus without touching the ocular surface.ResultsThe measured SM value was the highest upon awakening (4.44 ± 3.14 mm) and gradually decreased in the evening; 3.81 ± 3.12 at 9:00, 3.31 ± 2.72* at 12:00, 2.89 ± 1.88* at 15:00, 2.92 ± 1.87* at 18:00, 2.78 ± 1.85* at 21:00, and 2.89 ± 1.75* at bedtime with statistical significance compared to the value upon awakening (*P ConclusionOur results could identify diurnal variation of tear meniscus volume in the general population.

研究目的：泪液分泌对于维持健康眼表与视觉功能至关重要。多数健康受试者与干眼症患者均会在午后出现眼干症状加重的情况，但此前由于缺乏合适的检测手段，泪河体积的日间变化尚未被直接测量。本研究采用一种简易无创的自我检查技术——泪条泪河测量法（tear strip meniscometry, SM）。既往研究表明，该方法的检测值与施墨试验（Schirmer test）、泪膜破裂时间（tear break up time）检测，以及前节光学相干断层扫描（anterior optical coherence tomography）测量的泪河高度值具有强相关性。本研究旨在通过受试者自我检查采用SM法测量泪条湿润长度，以此获取泪河处泪液水相可用性的日间变化规律。
研究方法：本研究共纳入36名医护人员（平均年龄35.7岁），受试者每日借助镜子完成7次SM自我检查。检测操作时，将泪条置于下睑外侧泪河处5秒，且全程避免接触眼表组织。
研究结果：测得的SM值在晨起时达到峰值（4.44 ± 3.14 mm），随后于晚间逐渐降低：9:00时为3.81 ± 3.12，12:00时为3.31 ± 2.72*，15:00时为2.89 ± 1.88*，18:00时为2.92 ± 1.87*，21:00时为2.78 ± 1.85*，就寝时为2.89 ± 1.75*；所有晚间测量值与晨起峰值相比均具有统计学显著性差异（*P）。
研究结论：本研究结果明确了普通人群泪河体积的日间变化规律。