title: Dynamic distribution of artificial tears on the ocular surface.
abstract: OBJECTIVE
  To study the effects of artificial tear viscosity on tear film thickness, upper and lower tear menisci, and tear volume using optical coherence tomography.
  
  
  METHODS
  The central tear film and tear menisci before and immediately after the instillation of different artificial tears were imaged in 40 eyes of 20 healthy individuals. Carboxymethylcellulose sodium, 1.0% (viscosity, 70 cP), propylene glycol, 0.3%, and polyethylene glycol, 0.4% (10 cP), carboxymethylcellulose, 0.5% (3 cP), and isotonic sodium chloride solution (1 cP) were tested on 2 consecutive days. All measurements, including tear film thickness, the height, radius, and area of the tear meniscus, and the estimated tear volume, were obtained at 0, 5, 20, 40, and 60 minutes after instillation.
  
  
  RESULTS
  At instillation, all artificial tears and isotonic sodium chloride solution caused an increase in all tear variables (P < .001). Tear film thickness remained significantly elevated for all drops at 5 minutes (P < .001) and returned to baseline at 20 minutes. Other variables returned to baseline at 5 minutes. Comparing the different drops, tear film thickness and lower meniscus variables at instillation were increased with the more viscous drops (P < .05).
  
  
  CONCLUSIONS
  Optical coherence tomography demonstrated that all tear preparations, including isotonic sodium chloride solution, increased tear film thickness for at least 5 minutes and other variables immediately after instillation.
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 1638 NW 10th Ave, McKnight Bldg, Room 506, Miami, FL 33136, USA. jwang3@med.miami.edu
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Peter
authors.initials: P
authors.lastname: Simmons
authors.forename: James
authors.initials: J
authors.lastname: Aquavella
authors.forename: Joseph
authors.initials: J
authors.lastname: Vehige
authors.forename: Jayachandra
authors.initials: J
authors.lastname: Palakuru
authors.forename: Suk
authors.initials: S
authors.lastname: Chung
authors.forename: Changyong
authors.initials: C
authors.lastname: Feng
mesh_terms: D000328:Adult; D000869:Anterior Eye Segment / Q000378:metabolism*; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism*; D003228:Conjunctiva / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009883:Ophthalmic Solutions / Q000737:chemistry / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000378:metabolism*; D019946:Propylene Glycol / Q000378:metabolism*; D011446:Prospective Studies; D012965:Sodium Chloride / Q000378:metabolism; D041623:Tomography, Optical Coherence; D014783:Viscosity
chemical_list: D009883:Ophthalmic Solutions; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D019946:Propylene Glycol; D002266:Carboxymethylcellulose Sodium