Abstract: Tear meniscus volume following punctal occlusion

More evidence in favor of plugs. Sort of. Collagen plugs increase tear meniscus if you're dry, don't if you're not; do not affect Schirmer score if you're dry, actually lower it if you're not dry. Hm.

Tear meniscus volume in dry eye following punctal occlusion.
Invest Ophthalmol Vis Sci. 2009 Nov 20. [Epub ahead of print]
Chen F, Shen M, Chen W, Wang J, Li M, Yuan Y, Lu F.
School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, China.

Purpose: To use optical coherence tomography (OCT) to evaluate the effect of punctal occlusion on tear meniscus volume in dry eye patients.

Methods: Occlusion of both upper and lower puncta with collagen plugs was performed on one eye of 20 dry eye patients and 20 normal subjects. The upper and lower tear menisci were imaged simultaneously by real-time OCT before punctal occlusion and repeated on days 1, 4, 7 and 10 afterwards. The heights, cross-sectional areas, and volumes of the menisci were obtained. Schirmer I test with anesthesia and tear break-up time (TBUT) were also performed.

Results: At baseline, both upper and lower tear meniscus heights and volumes in dry eye patients were smaller than those in controls (P < 0.05). The lower tear meniscus volume was 0.28 +/- 0.09 mul in dry eye patients and 0.55 +/- 0.22 mul in controls at baseline (P<0.05). After punctal occlusion, the Schirmer I test scores of dry eye patients did not change (P>0.05), but the heights and volumes of both upper and lower tear menisci increased (P<0.05). In control subjects, Schirmer I test scores decreased (P<0.05), but heights and volumes of both upper and lower tear menisci did not change (P>0.05).

Conclusion: Punctal occlusion induced increases of both upper and lower tear meniscus volumes in dry eye patients. The absence of change in the tear menisci of control eyes may indicate the presence of an auto-regulatory mechanism in the tear system for maintaining a balance of tear volume.