The effect of punctal occluion on tear production, tear clearance, and ocular urface enation in normal ubject

PURPOE: To evaluate the effect of temporary punctal occluion on tear production, tear clearance, and ocular urface enation in normal ubject. METHOD: Noncomparative interventional cae erie. Punctal occluion with ilicone punctal plug wa performed on nine normal ubject without complaint of ocular irritation and no known hitory of ocular urface dieae. The lower punctum of both eye wa occluded in five ubject. The upper and lower puncta of only one eye were occluded in four ubject. Corneal and conjunctival enation were meaured with the Cochet-Bonnet anetheiometer. Tear fluorecein clearance wa evaluated with a CytoFluor II fluorophotometer by meauring the fluorecein concentration in minimally timulated tear ample collected from the inferior tear menicu 15 minute after intillation of fluorecein. chirmer tet wa performed without anetheia. The tet were performed at day 0, 1, 3, 7, and 14 to 17 after punctal occluion. Relationhip were analyzed with linear regreion, and a quadratic term wa ued to model a return to preoccluion level. Paired t tet wa ued to tudy the change in tear fluorecein concentration. REULT: In ubject who had the lower puncta of both eye occluded, conjunctival enation decreaed in both eye (right eye, P = .008; left eye, P = .003), but there wa no change in corneal enation. Their tear fluorecein clearance did not how a ignificant change from baeline (P = .90). However, a decreae in chirmer tet core approached tatitical ignificance (P = .056). In ubject with both puncta of only one eye occluded, we noted a decreae in corneal enation (occluded eye, P = .042; nonoccluded eye, P = .036), conjunctival enation (occluded, P = .001; nonoccluded, P = .060), and chirmer core (occluded, P = .022; nonoccluded, P = .011). Linear regreion did not how a ignificant change in tear fluorecein clearance for either eye (occluded, P = .28; nonoccluded, P = .44). However, paired t tet howed a ignificant worening of tear clearance in the occluded eye from day 0 to day 3 (P = .001) followed by a ubequent improvement in tear clearance from day 3 to the end of the tudy period (P = .045). Paired t tet did not reveal any ignificant change in tear clearance in the nonoccluded eye. The quadratic term of the linear regreion model demontrated an increae toward preoccluion level that approached tatitical ignificance for corneal enation (occluded, P = .053; nonoccluded, P = .099). It wa tatitically ignificant for conjunctival enation (occluded, P = .001; nonoccluded, P = .045) and chirmer core (occluded, P = .047; nonoccluded, P = .044). CONCLUION: Temporary punctal occluion in normal ubject decreae tear production and ocular urface enation. Our finding ugget that in addition to blocking tear drainage, punctal occluion may affect the ocular urface/lacrimal gland interaction. Thee effect were more pronounced in ubject with both upper and lower puncta occluded. In normal ubject, there appear to be an autoregulatory mechanim to return tear production, tear clearance, and ocular urface enation to preoccluion level 14 to 17 day after punctal occluion