Yen M T, Pflugfelder S C, Feuer W J
Ocular Surface and Tear Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
Am J Ophthalmol. 2001 Mar;131(3):314-23. doi: 10.1016/s0002-9394(00)00822-9.
To evaluate the effect of temporary punctal occlusion on tear production, tear clearance, and ocular surface sensation in normal subjects.
Noncomparative interventional case series. Punctal occlusion with silicone punctal plugs was performed on nine normal subjects without complaints of ocular irritation and no known history of ocular surface disease. The lower punctum of both eyes was occluded in five subjects. The upper and lower puncta of only one eye were occluded in four subjects. Corneal and conjunctival sensations were measured with the Cochet-Bonnet anesthesiometer. Tear fluorescein clearance was evaluated with a CytoFluor II fluorophotometer by measuring the fluorescein concentration in minimally stimulated tear samples collected from the inferior tear meniscus 15 minutes after instillation of fluorescein. Schirmer test was performed without anesthesia. The tests were performed at days 0, 1, 3, 7, and 14 to 17 after punctal occlusion. Relationships were analyzed with linear regressions, and a quadratic term was used to model a return to preocclusion levels. Paired t test was used to study the change in tear fluorescein concentration.
In subjects who had the lower puncta of both eyes occluded, conjunctival sensation decreased in both eyes (right eye, P =.008; left eye, P =.003), but there was no change in corneal sensation. Their tear fluorescein clearance did not show a significant change from baseline (P =.90). However, a decrease in Schirmer test scores approached statistical significance (P =.056). In subjects with both puncta of only one eye occluded, we noted a decrease in corneal sensation (occluded eye, P =.042; nonoccluded eye, P =.036), conjunctival sensation (occluded, P =.001; nonoccluded, P =.060), and Schirmer scores (occluded, P =.022; nonoccluded, P =.011). Linear regression did not show a significant change in tear fluorescein clearance for either eye (occluded, P =.28; nonoccluded, P =.44). However, paired t test showed a significant worsening of tear clearance in the occluded eye from day 0 to day 3 (P =.001) followed by a subsequent improvement in tear clearance from day 3 to the end of the study period (P =.045). Paired t test did not reveal any significant changes in tear clearance in the nonoccluded eye. The quadratic term of the linear regression model demonstrated an increase toward preocclusion levels that approached statistical significance for corneal sensation (occluded, P =.053; nonoccluded, P =.099). It was statistically significant for conjunctival sensation (occluded, P =.001; nonoccluded, P =.045) and Schirmer scores (occluded, P =.047; nonoccluded, P =.044).
Temporary punctal occlusion in normal subjects decreases tear production and ocular surface sensation. Our findings suggest that in addition to blocking tear drainage, punctal occlusion may affect the ocular surface/lacrimal gland interaction. These effects were more pronounced in subjects with both upper and lower puncta occluded. In normal subjects, there appears to be an autoregulatory mechanism to return tear production, tear clearance, and ocular surface sensation to preocclusion levels 14 to 17 days after punctal occlusion.
评估正常受试者暂时性泪点阻塞对泪液生成、泪液清除及眼表感觉的影响。
非对照性干预病例系列研究。对9名无眼部刺激症状且无眼表疾病已知病史的正常受试者进行硅胶泪点塞阻塞泪点。5名受试者双眼下泪点被阻塞。4名受试者仅单眼的上下泪点被阻塞。使用Cochet-Bonnet麻醉计测量角膜和结膜感觉。通过CytoFluor II荧光光度计评估泪液荧光素清除情况，方法是在滴入荧光素15分钟后，测量从下泪湖采集的最小刺激泪液样本中的荧光素浓度。在无麻醉情况下进行Schirmer试验。在泪点阻塞后的第0、1、3、7天以及第14至17天进行各项测试。采用线性回归分析相关性，并使用二次项来模拟恢复至阻塞前水平的情况。采用配对t检验研究泪液荧光素浓度的变化。
在双眼下泪点被阻塞的受试者中，双眼结膜感觉均下降（右眼，P = 0.008；左眼，P = 0.003），但角膜感觉无变化。其泪液荧光素清除率与基线相比无显著变化（P = 0.90）。然而，Schirmer试验评分的降低接近统计学意义（P = 0.056）。在仅单眼的上下泪点被阻塞的受试者中，我们注意到角膜感觉下降（阻塞眼，P = 0.042；未阻塞眼，P = 0.036）、结膜感觉下降（阻塞眼，P = 0.001；未阻塞眼，P = 0.060）以及Schirmer评分下降（阻塞眼，P = 0.022；未阻塞眼，P = 0.011）。线性回归显示，任何一只眼睛的泪液荧光素清除率均无显著变化（阻塞眼，P = 0.28；未阻塞眼，P = 0.44）。然而，配对t检验显示，阻塞眼从第0天到第3天泪液清除情况显著恶化（P = 0.001），随后从第3天到研究期末泪液清除情况有所改善（P = 0.045）。配对t检验未显示未阻塞眼泪液清除有任何显著变化。线性回归模型的二次项显示，角膜感觉（阻塞眼，P = 0.053；未阻塞眼，P = 0.099）、结膜感觉（阻塞眼，P = 0.001；未阻塞眼，P = 0.045）和Schirmer评分（阻塞眼，P = 0.047；未阻塞眼，P = 0.044）均朝着阻塞前水平增加，接近统计学意义。
正常受试者暂时性泪点阻塞会减少泪液生成并降低眼表感觉。我们的研究结果表明，泪点阻塞除了阻断泪液引流外，可能还会影响眼表/泪腺的相互作用。这些影响在上下泪点均被阻塞的受试者中更为明显。在正常受试者中，似乎存在一种自动调节机制，可使泪液生成、泪液清除及眼表感觉在泪点阻塞后14至17天恢复至阻塞前水平。
