title: Effects of Punctal Occlusion on Clinical Signs and Symptoms and on Tear Cytokine Levels in Patients with Dry Eye.
abstract: To investigate changes in signs, symptoms, and tear cytokines following punctal plug occlusion in patients with dry eye.
  
  
  
  A single-center study was conducted at Singapore Eye Research Institute. Nonabsorbable punctal plugs were inserted in the lower punctum of both eyes in patients with moderate dry eye. Over 3 weeks, in the more severe eye, dry eye symptoms, fluorescein corneal staining, Schirmer I (without topical anesthesia) test, tear film breakup time (TFBUT), and safety were assessed. Cytokine and matrix metalloproteinase-9 (MMP-9) levels in tear samples were measured.
  
  
  
  Twenty-nine patients (mean age 49.8 years) with moderate dry eye were evaluated. At baseline, mean (standard deviation) global symptoms score was 53.8 (26.5), Schirmer I test score was 5.1 (2.8) mm, and TFBUT was 2.2 (0.6) seconds. After 3 weeks, punctal occlusion significantly reduced global irritation symptoms score (P<.001) and decreased fluorescein staining in all zones (P<.01) except the inferior zone (P=.42). No significant association between levels of cytokines or MMP-9 and either TFBUT or global irritation symptoms were observed at baseline. Levels of several cytokines and MMP-9 were higher in patients with Schirmer I test scores ≤8 mm at baseline. After 3 weeks of punctal occlusion, no significant changes in overall cytokine or MMP-9 levels were observed.
  
  
  
  Punctal plug occlusion provided symptomatic relief and reduced fluorescein staining in all except the inferior zone. However, insertion of punctal plugs had minimal effect on tear cytokines and MMP-9 levels, suggesting a need for earlier treatment with anti-inflammatory agents for management of dry eye disease.
authors.affiliation: Singapore Eye Research Institute, National Eye Centre, Singapore, Singapore; Yong Loo Lin School of Medicine, Singapore, Singapore; Singapore National Eye Center, Singapore, Singapore; Duke-NUS Medical School, Singapore, Singapore. Electronic address: louis.tong.h.t@snec.com.sg.
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.affiliation: Singapore Eye Research Institute, National Eye Centre, Singapore, Singapore.
authors.forename: Roger
authors.initials: R
authors.lastname: Beuerman
authors.affiliation: Allergan plc, Singapore, Singapore.
authors.forename: Susan
authors.initials: S
authors.lastname: Simonyi
authors.affiliation: Allergan plc, Irvine, CA, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Hollander
authors.affiliation: Allergan plc, Irvine, CA, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Stern
mesh_terms: D016207:Cytokines; D015352:Dry Eye Syndromes; D006801:Humans; D007765:Lacrimal Apparatus; D008875:Middle Aged; D013666:Tears; D016896:Treatment Outcome
chemical_list: D016207:Cytokines
keywords: cytokine; dry eye; matrix metalloproteinase; punctal plug; tear