title: Novel tear interferometer made of paper for lipid layer evaluation.
abstract: OBJECTIVE
  To introduce a novel interferometer and provide clinical data based on its use.
  
  
  METHODS
  Twenty-two normal subjects, 27 patients with dry eye syndrome, 1 patient with obstructive meibomian gland dysfunction, and 2 patients with ocular graft-versus-host disease were included in the study. We cut a piece of copy paper to create an interferometer comprising a handle, a window, and an illumination area. The patient sits in front of a biomicroscope with his or her head fixed on the headrest. The examiner holds the handle of the interferometer 10 mm from the front of the patient's eye. The examiner positions the illumination beam of the biomicroscope at the "illumination area." The examiner then observes a lipid layer interference pattern on the cornea through the window.
  
  
  RESULTS
  For the normal subjects, wave or amorphous patterns with white or grey color were observed in interferometry. The mean estimated lipid layer thickness in the dry eye group (43 ± 9 nm) was significantly thinner than that of the normal group (59 ± 29 nm) (P = 0.021). For the patient with obstructive meibomian gland dysfunction, interferometry revealed a white interference pattern (30 nm). For ocular graft-versus-host disease, the lipid pattern was brown and blue (165 nm). Patients felt no discomfort, and no complications occurred during examination.
  
  
  CONCLUSIONS
  We could successfully obtain photographs of the lipid layer pattern with this novel interferometer without additional equipment or cost. This interferometer may be useful for research regarding the pathophysiology, diagnosis, and treatment of dry eye.
authors.affiliation: *Department of Ophthalmology, Chuncheon Sacred Heart Hospital College of Medicine, Hallym University, Chuncheon, Korea; †Department of Ophthalmology, Bucheon St Mary's Hospital College of Medicine, The Catholic University of Korea, Bucheon, Korea; and ‡Department of Ophthalmology, Seoul St Mary's Hospital, Seoul, Korea.
authors.forename: Ho Sik
authors.initials: HS
authors.lastname: Hwang
authors.forename: Eun Chul
authors.initials: EC
authors.lastname: Kim
authors.forename: Man Soo
authors.initials: MS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D015352:Dry Eye Syndromes / Q000175:diagnosis*; D005141:Eyelid Diseases / Q000175:diagnosis*; D005260:Female; D006086:Graft vs Host Disease; D006801:Humans; D007368:Interferometry / Q000295:instrumentation*; D008055:Lipids / Q000032:analysis*; D008297:Male; D008537:Meibomian Glands / Q000473:pathology*; D008875:Middle Aged; D010209:Paper; D013666:Tears / Q000737:chemistry*
chemical_list: D008055:Lipids