At last, an interesting plug study that did not involve smartplug complications.

This one compares people who ONLY got upper plugs with those who ONLY got lower plugs. Seems like we hardly hear about anyone doing uppers only these days.

Visual Function Changes After Punctal Occlusion With the Treatment of Short BUT Type of Dry Eye.

PURPOSE:
To evaluate visual function changes after punctal plug (PP) occlusion in patients with short breakup time of tear film (BUT) type of dry eyes.

METHODS:
A prospective comparative study was performed in 43 eyes of 43 dry eye patients with short BUTbreakup time of tear film receiving PP occlusion. Patients were divided into 2 groups as those receiving only upper or only lower occlusion. Functional visual acuity measurements, tear function evaluations, and questionnaire on satisfaction with treatment in relation to presence of epiphora were performed before and 1 month after PP insertion.

RESULTS:
Twenty eyes of 43 eyes (46.5%) with only lower occlusion and 17 eyes of 43 eyes (39.5%) with only upper occlusion showed satisfactory outcomes with treatment. One of 43 eyes (2.3 %) had epiphora. Vital staining scores and BUT values significantly improved in both groups after occlusion. The mean logarithm of the minimum angle of resolution functional visual acuity value significantly improved only in eyes receiving upper PP occlusion.

CONCLUSION:
Upper PP occlusion seems to be associated not only with improvement of tear stability, vital staining scores, and treatment-related satisfaction but also with better quality of visual function.
Cornea. 2012 Feb 21. [Epub ahead of print]
Kaido M, Ishida R, Dogru M, Tsubota K.
Source
*Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan †Johnson & Johnson Department of Ocular Surface and Visual Optics, Keio University School of Medicine, Tokyo, Japan.