May 2008
Volume 49, Issue 13
ARVO Annual Meeting Abstract  |   May 2008
The Effects of Unilateral Punctal Occlusion on Tear Clearance and Tear Cytokines in Normal Human Subjects
Author Affiliations & Notes
  • M. LaFrance
    Vision Science, Univ of Alabama at Birmingham, Helena, Alabama
  • R. Fullard
    Vision Science, Univ of Alabama at Birmingham, Helena, Alabama
  • Footnotes
    Commercial Relationships  M. LaFrance, None; R. Fullard, None.
  • Footnotes
    Support  2007 UABSO Clinical Research Advisory Committee Grant; NIH Grant EY03039
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 427. doi:
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      M. LaFrance, R. Fullard; The Effects of Unilateral Punctal Occlusion on Tear Clearance and Tear Cytokines in Normal Human Subjects. Invest. Ophthalmol. Vis. Sci. 2008;49(13):427. doi:

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: : It has been proposed that punctal occlusion may alter tear cytokine concentrations based on the facts that: (1) tear clearance, a measure of the balance between tear production and elimination, declines following occlusion and (2) reduced tear clearance and increased levels of pro-inflammatory tear cytokines are correlated in dry eye patients. This study compares tear clearance values and the level of 24 tear cytokines following temporary unilateral punctal occlusion.

Methods: : One randomly assigned eye of 23 normal subjects received superior and inferior unilateral intracanalicular punctal occlusion with six-month dissolvable HerrickTM plugs. Nonstimulated tear samples from both eyes were collected via micropipette (stored at -80 C) and tear clearance was measured using the Standardized Visual Scale Test (Macri 2000) prior to occlusion and again at 1, 4, and 7-weeks post occlusion. Tear cytokine concentrations were determined using a sandwich-ELISA based cytometric bead assay. Wilcoxon’s Matched Pairs test was used to compare contralateral tear clearance values at each interval and a generalized linear model with factors treatment and time was used to compare cytokine concentrations.

Results: : No between eye differences in tear clearance values were found prior to occlusion (p = 0.23). Following occlusion, reduced tear clearance was observed for the eye of occlusion at week 1 (p = 0.02), week 4 (p = 0.01), and week 7 (p < 0.0001). No statistically significant differences were observed between occluded or control eyes, nor was there a statistically significant interaction with time for the tear cytokines assayed: IL-1ra, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-17, G-CSF, GM-CSF, IFNγ, Eotaxin, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-ββ, RANTES, and VEGF.

Conclusions: : Unilateral punctal occlusion reduces tear clearance when compared to the fellow non-occluded eye in normal subjects. However, this did not alter the concentration of tear cytokines compared to pre-occlusion levels or when compared to the fellow non-occluded eyes. Therefore, punctal occlusion per se does not appear to alter the immune status of the tear film.

Keywords: cornea: tears/tear film/dry eye • cytokines/chemokines 

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