This study will investigate the impact of punctal occlusion on the ocular microbial flora. Current thought is that punctal occlusion causes retention of inflammatory mediators on the ocular surface which may produce pathology, we hypothesize that blockage of the nasolacrimal drainage system may allow colonization of the ocular surface by potentially pathogenic ubiquitous organisms (which may produce exotoxins and other biologic products) that may be responsible for signs and symptoms seen in some patients. Additionally, the presence of the silicone foreign body(punctal plug) may act as a nidus for bacterial adhesion with biofilm production (which is known to occur with Pseudomonas sp and other organisms). There would thus be a paradigm shift of our current understanding of the pathophysiology of punctal occlusion. Additionally, the choice of antimicrobials for the treatment of infections in patients with punctal occlusion may need to be modified if the microbial flora is found to be different in patients with punctal occlusion.